Masterthesis: ECONOMIC CONSIDERATIONS IN THE THERAPY OF GLAUCOMA

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Lithuanian University of Health Sciences Faculty of Medicine

Department of Ophthalmology

Masterthesis:

ECONOMIC CONSIDERATIONS IN THE THERAPY OF

GLAUCOMA

Author: Albin Gross

Supervisor:

Prof.dr. Ingrida Janulevičienė

Kaunas 2018/2019

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SUMMARY

Name of the author: Albin Gross

Research title: Economic considerations in the therapy of glaucoma Aim:

To determine economic considerations in the therapy of glaucoma.

Objectives:

1. To determine factors that contribute to the costs in the therapy of glaucoma and to compare these factors between patients who receive medical treatment and patients who receive surgical treatment for their glaucoma. 

2. To evaluate the quality of life of the glaucoma patients by using a questionnaire and to compare the quality of life between patients who receive medical treatment and patients who receive surgical glaucoma treatment. 

3. To put the outcomes of the economic factors in relation to the quality of life of the glaucoma patients to determine which treatment method is more cost-eﬀective and which treatment method is contributing to a better quality of life.

Methodology:

The study is a cross-sectional survey conducted at the Lithuanian University of Health Sciences. The study was carried out during January and February of 2019 among glaucoma patients of the Clinic of Ophthalmology at Kauno Klinikos of the Lithuanian University of Health Sciences.

The participants were answering an original questionnaire that was created and adapted to the main goals of our research according to literature review (56, 57). The study population and sample size of this study consisted of 50 patients with a diagnosis of glaucoma for at least 5 years. The sample size was further subdivided into 30 patients who are receiving conservative treatment and 20 patients who received surgical treatment for their glaucoma.

Results:

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Their costs consisted of taking more antiglaucoma drugs (p=0,024) and visiting their ophthalmologist more often for follow-up (p=0,000).

The quality of life was in this study on average lower for surgically treated patients than for conservatively treated patients (p=0,035) because taking glaucoma eye drops was more inconvenient (p=0,01) and more difficult (p=0,004) for them and they were more affected by the restriction of certain activities that they are not able to do any longer due to suffering from glaucoma (p=0,009).

Conclusion:

In conclusion, our study showed that surgically treated patients had higher costs and a lower quality of life. They were causing higher costs by needing more anti-glaucoma drugs, by having had to undergo surgical procedures and by visiting their ophthalmologist more often for follow-up.

Additionally to the higher costs in their therapy, surgically treated patients were also having on average a lower quality of life, mainly due to inconveniences and difficulties in taking glaucoma eye drops and the restricted activities they were no longer able to do due to suffering from glaucoma. But it should also be considered that the assessment of the quality of life with a questionnaire has several limitations, namely that it is subjective. Patients with a similar degree of disability may rate their quality of life differently.

Glaucoma is a very costly disorder and more investigation on cost-eﬃcient strategies in the therapy of glaucoma need to be done.

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CONFLICTS OF INTERESTS

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CHAPTER 1: INTRODUCTION

Glaucoma is not a single disease but a group of neurodegenerative diseases aﬀecting the optic nerve and is in most cases associated with increased intraocular pressure (IOP) (Schellack, 26).

As the diseases progress it causes gradually increasing long-lasting visual field loss and at the final stage blindness.

Around 60 million people worldwide suﬀer from glaucoma and around 8,4 million people are blind as the result of the suﬀering of glaucoma (Cook et al. 28). It is the second leading cause of blindness in the world, after cataracts (Schellack, 26).

It is mainly a disease of the elderly and due to that and the aging population, these numbers are likely to increase over time. Predictions state that in 2020, 80 million people and in 2040, 111,8 million people will suﬀer from glaucoma (Schellack, 26), (Giangiacomo et al. 29). 87% of the patients of angle closure glaucoma in 2020 will be Asian and 70% will be women. In 2020, bilateral blindness caused by glaucoma will aﬀect more than 11 million people worldwide. (Giangiacomo et al. 29)

In the United States glaucoma accounts for over 10 million doctors visits per year (33) and the U.S government has estimated costs of 1.5 billion dollars per year for a loss of income tax revenues and health care expenditures due to glaucoma (34).

In our current time people tend to get older and older and therefore also the number of diseases of the elderly such as glaucoma are increasing. During the recent years and decades we constantly recognized not only an increase of diseases which are common in elderly people but also a significant increase in the total costs in health care causing a significant economic burden on society and since our resources are not finite we constantly have to work on spending the given resources as eﬃciently as possible and therefore have to find ways and solutions in making certain diagnostic and treatment options cost-eﬀective. (Tuulonen, 1)

The first line therapy of open-angle glaucoma consists of intraocular pressure lowering eye drops. But the intraocular pressure can also be lowered by surgery. Certain studies that compared the cost-eﬀectiveness between laser surgery and eye drops came to the conclusion that in the long term surgical treatment is more eﬀective since over time the

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costs for conservative therapy are accumulating and are exceeding the initial costs of the surgical procedure (Lee R et al. 35, Cantor LB et al. 36).

Nonetheless, despite all the costs that come along with the therapy of glaucoma we should not forget the quality of life of the patients. It can easily be the case that a more

cost-eﬀective treatment option is leading to decreased outcome in the quality of life, so the quality of life of a certain treatment option should be also included when the cost-eﬀectiveness of a certain treatment method is assessed.

Our study therefore wants to determine the certain factors that contribute to the costs in the therapy of glaucoma, to estimate the quality of life of the patients of these two diﬀerent treatment options and to compare these factors between conservatively and surgically treated patients to find out which treatment method is more cost-eﬀective and which is leading to a better outcome in the quality of life of the patients.

The outcome of our study might bring more awareness to the increasing costs in the therapy of glaucoma and why it is important to not only introduce new treatment options but also to search for possibilities to spend less money on diagnosis and treatment while still oﬀering good care for the patients. Every penny can only be spent once and if too much money is being spent on one disease or one treatment option it might lack for the treatment for

another disease or another treatment option (Smith et al. (2). That is why it is crucial to think about ways on how to be more cost-eﬀective in terms of glaucoma care and then

additionally to perform further research in order to investigate if those thoughts or hypothesis are true in a scientific setting.

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CHAPTER 2: AIM AND OBJECTIVES

Aim:

To determine economic considerations in the therapy of glaucoma.

Objectives:

1. To determine factors that contribute to the costs in the therapy of glaucoma and to compare these factors between patients who receive medical treatment and patients who receive surgical treatment for their glaucoma. 

2. To evaluate the quality of life of the glaucoma patients by using a questionnaire and to compare the quality of life between patients who receive medical treatment and patients who receive surgical glaucoma treatment. 

3. To put the outcomes of the economic factors in relation to the quality of life of the glaucoma patients to determine which treatment method is more cost-eﬀective and which treatment method is contributing to a better quality of life.

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CHAPTER 3: LITERATURE REVIEW

3.1. What is glaucoma?

Glaucoma is not a single disease but a group of neurodegenerative diseases aﬀecting the optic nerve and is in most cases associated with increased intraocular pressure (IOP) (Schellack, 26)

As the diseases progress it causes gradually increasing long-lasting visual field loss and at the final stage blindness.

Pathophysiology:

The entire pathophysiology of glaucoma is not completely understood so far. Up to now, it is only known that retinal ganglion cells die via apoptosis.

Open-angle glaucoma presents almost in 90 percent of all case in a physiological dysbalance between the secretion and drainage of aqueous humour.

The ciliary process produces aqueous humour and it is drained by the trabecular meshwork and the uveoscleral outflow pathway (Schellack, 26).

The balance between the secretion and the drainage of aqueous humour determines the intraocular pressure (Weinreb et al. 27).

Epidemiology:

Around 60 million people worldwide suﬀer from glaucoma and around 8,4 million people are blind as the result of the suﬀering from glaucoma (Cook et al, 28). It is the second leading cause of blindness in the world, after cataracts (Schellack, 26).

It is mainly a disease of the elderly and due to that and the aging population, these numbers are likely to increase over time. Predictions state that in 2020, 80 million people and in 2040, 111,8 million people will suﬀer from glaucoma (Schellack, 26), (Giangiacomo et al. 29).87% of the patients of angle closure glaucoma in 2020 will be Asian and 70% will be women. In 2020, bilateral blindness caused by glaucoma will aﬀect more than 11 million people worldwide (Giangiacomo et al. 29).

According to the statistics of the World Health Organization it is estimated that around 37 million people worldwide are blind. Every year, an additional 1-2 million persons go blind. Without proper interventions the number of blind people will increase to 75 million by 2020.

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75% of this cases are treatable and/or preventable. Glaucoma comprises 12,3% of

blindness worldwide. It is the leading cause if global irreversible blindness and the second leading cause of blindness worldwide after age-related macular degeneration. Restoration of sight is one of the most cost-eﬀective interventions in health care. The successful

implementation of the Vision 2020 program should result in a minimum saving of 102 billion US-Dollars in lost productivity by the years 2020.

Main risk factors for glaucoma blindness are noncompliance with the treatment regimen (Chen, 48), late presentation (Known et al. 49), (Oliver et al. 50), greater severity of the disease at the time of diagnosis was also associated with subsequent progression to blindness despite treatment (Chen, 48), (Hattenhauer et al. 51), (Grant et al. 52) and lack of knowledge about glaucoma (Chen PP, 53).

Treatment:

The main goals for glaucoma treatment are to slow the progression of the disease and to preserve the quality of life of the patient (Weinreb et al. 27). The only proven method to treat glaucoma is a reduction of the intraocular pressure. The target of the reduction of the

intraocular pressure lies between 20 to 50% but there is a need for continuous reassessment during the patient follow-up (Weinreb et al. 27).

The intraocular pressure is reduced with drugs form diﬀerent pharmacological groups. These groups are beta-blockers, alpha 2 agonists, prostaglandins analogues, carbonic anhydrase inhibitors.

Beta-blockers and carbonic anhydrase inhibitors reduce the intraocular pressure by reducing the production of aqueous humour.

Prostaglandin analogues decrease the intraocular pressure by increasing the outflow of aqueous humour through the uveoscleral pathway by decreasing the outflow resistance. And alpha 2 agonists decrease the intraocular pressure by both decreasing the production and increasing the outflow of aqueous humour through the uveoscleral pathway by

decreasing the outflow resistance.

Prostaglandin analogues are considered as the first line treatment in open-angle glaucoma and in decreasing the intraocular pressure (Weinreb et al.27).

Beta-blockers, carbonic anhydrase inhibitors and alpha agonist are second-line drugs for decreasing the intraocular pressure and are used when there is a contraindication or intolerance to prostaglandin analogues (Weinreb et al. 27).

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When medical treatment with the above-mentioned drugs alone does not achieve the required reduction in intraocular pressure with tolerable side eﬀects, laser (trabeculoplasty) or incisional surgeries (trabeculectomy) are indicated (Weinreb et al. 27).

Surgical interventions should be considered for patients with glaucoma „at risk of progressing to slight loss despite treatment“ (NICE, 54). Patients attending for

trabuculectomy had faster average rates of visual field loss prior to surgery than published values for the general glaucoma population (Foulsham et al. 55).

3.2. Cost-eﬀectiveness:

As already mentioned in the introduction, Tuulonen [1] stated that our current way of practice in glaucoma is still far from being perfect. She especially criticizes that there is currently still a lot under and overdiagnosis and treatment going on. We are unaware of about half of the patients with glaucoma since they haven’t been diagnosed yet and according to the author also about half of the patients who are being treated for glaucoma do not even have glaucoma.

She further criticizes the patients' adherence to the prescribed treatment regimen and states that also around 50% of glaucoma patients do not use their eye drops regularly and or properly.

Especially, because of our current far from being optimal practice in handling glaucoma Tuulonen states that it is important to think about it, make suggestions and improve the situation since the goal of using our limited resources eﬀectively should according to her always be to produce the best eye health which the author describes as increasing both the length and quality of seeing years.

In order to establish that, the author states that choices must be made upon prioritizing all interventions, like screening, case finding, diagnostic and follow-up tests, as well as diﬀerent treatment modalities, care processes and practices because when resources have been used for one purpose they cannot be used for something else. A dollar can only be spent once.

By saying that, Tuulonen confirms which was already said by Smith et al. in 2002 [2]. In their article, they already mentioned that cost-effectiveness is of importance since our resources are limited and it is, therefore, necessary to use the given resources in the most efficient and effective way.

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They then were breaking down, that cost-eﬀectiveness merely describes the way of making choices in spending the given resources in an eﬀective and useful way.

But in order to evaluate the cost-eﬀectiveness in health care, we have to know the cost of an intervention and its eﬀectiveness according to Smith et al. Therefore, the authors state that costs need to be identified, measured and valued. Only then the data can be interpreted and put into relationship with each other.

This goes along with Tuulonen’s [1] definition of cost-eﬀectiveness as being an analysis in which health eﬀects are being measured by indicators such as lives saved, life years or seeing years gained, years of blindness avoided, changes in visual acuity, intraocular

pressure or visual field indices and then are related to the costs. She furthermore mentioned that it is only possible to show cost-effectiveness in relation to a defined alternative, an intervention can therefore only be cost-effective when it is compared to another intervention and is therefore not cost/effective in itself.

Tuulonen [1] regards cost-utility as the best method of economic evaluation in health care. She describes it as a special form of cost-eﬀectiveness analysis in which health eﬀects are measured in term of changes in either length or quality. Cost-utility is therefore measured usually in quality-adjusted life years and the changes of quality-adjusted life years are then related to changes in costs.

This description of Tuulonen [1] confirms the description of Smith et al. [2] who described cost-utility as a quantification of the cost of attaining a given level of health gain which is measured in quality-adjusted life years.

Finally, Smith et al. were breaking down that the result from a cost-effectiveness analysis is resulting in a ratio which measures the cost per unit of health effect and then it is possible to compare different treatment options in terms of their health effect and costs. But in order to do that all costs have to be known and since, according to Smith et al, the direct costs, meaning the costs for hospitalizations, drugs, doctors fees, lab costs, rehabilitation costs and long term care costs are fairly easy to measure they criticized that the determination of the indirect costs such as loss of potential income, productivity loss, morbidity loss and mortality loss are quite difficult to put into numbers.

Before we are going to dive deeper let’s firstly use some of Tuulonen’s [1] definitions of some economic terms for a better understanding:

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Eﬀectiveness describes the outcome in everyday practices.

Efficiency is the way health care procedures are assessed economically which means that the produced health effects are weighed against the costs which are needed to attain them. Efficiency therefore according to Tuulonen presents a relationship between health effects and costs.

There are several types of economic analyses: cost-eﬀectiveness analyses, cost-utility analyses, cost-minimization analyses, cost-benefit analyses and decision analytical modelling analyses.

Cost-effectiveness analysis means that health effects are measured by indicators such as lives saved, life years or seeing years gained, years of blindness avoided, changes in visual acuity, intraocular pressure or visual field indices and they are put into relation to costs. Cost-effectiveness can only be shown in relation to a defined alternative. Therefore, an intervention is never cost effective in itself, only in relation to another intervention. Cost-utility analyses are regarded as the best method of economic evaluation in health care. It is a special form of cost-effectiveness analysis in which health effects are measured in terms of changes in either length or quality in life. It is measured usually in

quality-adjusted life years. The changes of quality-quality-adjusted life years are then put in relation to changes in costs.

Cost-minimization analyses are used when several treatments lead to the same clinical outcome. Then it is possible to compare which of these treatments produces the least amount of costs. But this happens quite rarely since clinical outcomes are usually never exactly the same among diﬀerent treatment options.

Cost-benefit analysis are the kind of analyses when health effects which are measured in monetary terms are weighted against costs. It measures whether the monetary benefits of a treatment or a drug are greater than the monetary costs. But unfortunately, it is difficult to put the health effects into monetary terms.

Analytical economic modelling analyses are a method of synthesizing existing data and evidence available on the costs and outcomes of alternative interventions. Markov modelling is such an economic model, in it the disease is divided into distinct states and then transiton probabilities are assigned for movements between these states over a discrete time period, which is called a cycle. Such a model is then run over a large number of cycles so that it is possible to estimate the long-term costs and outcomes associated with a particular disease. It is mainly used and suited for the calculation of quality-adjusted life years and it is used

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since usually the follow-up of clinical trials is too short for the purposes of economic

evaluation. So, in such models, long term outcomes can be predicted from the data of short term trials.

3.3. Burdens and costs

Rahmen et al. [3] were calculating the direct health care costs of the glaucoma treatment over the entire lifetime in Scotland. Therefore, they extracted the data of 1136 patients who were visiting the glaucoma clinic at the Glasgow Royal Infirmary and out of these 1136 patients' they found 106 patients, 53 males and 53 females who were oﬀering enough data to make calculations for a lifetime. The mean number of years these patients were attending the glaucoma clinic was 7,05 years. The mean cost of glaucoma treatment they calculated was in total over the lifetime 3001 GBP, with an annual cost of 475 GBP. Out of these costs, non-drug cost made up 66% and drug costs made up 34% of the lifetime cost.

This shows that economic burden of glaucoma is indeed significant and more importantly it shows that drugs make up around a third of the total direct costs, which is quite a large amount.

In another study of Olsen et al. [4] in which they analyzed the glaucoma costs in Denmark, the drug costs made up even 57% of the total costs. And according to that, they concluded that medications make up the largest amount of the treatment costs of glaucoma. In

addition, they were also investigating the impact that treatment changes had on the costs and came to the conclusion that with the number of treatment regimens also the treatment costs are increasing, in numbers from 305 Euro for patients under their initial treatment regimen to 740 Euro for patients with 3 or more regimens.

This enables us to realize that a proper initial treatment regimen is crucial in keeping the costs of the glaucoma treatment in a cost-eﬀective range.

The following study of Pezullo et al. [5] enables us to look on the subject of the economic burden of glaucoma in a larger scale. The authors of this study merely were investigating the total economic impact of sight loss and blindness in the adult population in the United Kingdom in 2013. Hereby, they paid attention not only on the direct costs as in the

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a burden these costs are on health care and society, especially for the socioeconomics of a country.

In their results, they estimated that sight loss and blindness from age-related macular degeneration, cataract, diabetic retinopathy and glaucoma were aﬀecting 1.93 million people in the United Kingdom and caused costs of 3.0 billion GBP in terms of direct health care costs and 6.65 billion pounds in terms of indirect health care costs. Additionally, they also calculated the value of the loss of healthy life associated with sight loss and blindness and estimated an amount of 19.5 billion GBP.

With this study, the authors showed that indeed sight loss and blindness imposes significant costs on the public, health care and also private expenditures.

Dirani et al. [6] went even further in their literature review. They did not only examine the economic impact of primary open-angle glaucoma in Australia since 1985, they even made a prediction about the economic impact of glaucoma till 2025 out of the data from 1985 to the present. They predicted that the prevalence of glaucoma will increase in Australia about more than a third till 2025 and the direct health care costs are about to double from 355 million AUD to 784 million AUD and the total costs for glaucoma in which the direct health care costs, as well as the indirect costs of the loss of sight, are included are about to increase significantly from 1.9 billion AUD to 4.4 billion AUD within that period. These significant increases are according to the authors mainly due to the aging population but also due to better diagnostic measures.

This Australian study illustrates ultimately what a significant economic burden glaucoma possesses.

Since most cases of glaucoma are undiagnosed it is obvious to ask if not some programs can be invented to increase the number of diagnoses in patients who are having glaucoma but are unaware of it.

Such a program was introduced in Philadelphia and is called the „Philadelphia Glaucoma Detection and Treatment Project“. It was introduced by the community centres of

Philadelphia.

Pizzi LT et al. [7| measured in their analysis the total cost of that program and additionally the cost per case of detected glaucoma and the cost per case of any other detected ocular disease by that program. They further calculated the costs of examinations and educational workshops by examining the data of 1949 participants of that program. The mean total examination cost per participant was 139 dollars. The cost per case of newly identified

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glaucoma was 420 dollars and the cost per case for any ocular disease identified was 273 dollars.

In conclusion, the authors were satisfied with these numbers and showed that this program is oﬀering a significant health benefit especially for people who are unaware of their disease. They mentioned that this program could be taken as a reference in order to introduce other similar programs in order to increase diagnoses of the undetected cases of glaucoma.

Now, that we know about the general cost potential of glaucoma we should pay attention to the cost of individual cases and how the costs diﬀer in diﬀerent stages of severity of

glaucoma. Till 2005, the direct costs of glaucoma and consequently the resource utilization for glaucoma in Europe were unknown. Only then a study was bringing awareness to the cost of glaucoma and bringing them into relation with the severity of the disease.

Traverso al. [8] selected from a total number of 1655 cases 194 patients with the following diagnoses: primary open-angle glaucoma, glaucoma suspect, ocular hypertension and normal tension glaucoma and divided them into five diﬀerent groups according to their severity.

The researches came to the conclusion that the direct costs of glaucoma tend to increase as the disease becomes more severe. In their study, the cost increased by about 86 euro for each stage from 455 euro for stage 0 to 969 euro for stage 4 for every patient.

Also, the number of medication costs of the direct costs for glaucoma were calculated and ranged between 42% to 56% for all stages of glaucoma.

Upon these result, the authors concluded that resource utilization and direct costs of glaucoma treatment is increasing with the worsening of the disease.

This was confirmed by Varma et al. [25] who also stated in their literature review that medications are causing the majority of the costs and that the majority of the glaucoma patients are old and undiagnosed and that as the disease progresses the overall economic burden is increasing which has additionally been shown by Fiscella et al. [24] in their review about costs of glaucoma in which they confirmed that most studies show that the direct costs of glaucoma are increasing as the disease progresses to a more advanced stage. And also Hagman [23] found out in her comparison, of the resource utilization in the treatment of glaucoma in two diﬀerent finish cities, that higher stages of glaucoma cause higher costs and therefore a higher resource consumption.

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Therefore, one can expect that identifying glaucoma early and managing glaucoma eﬀectively and therefore delaying the progression of the disease would be reducing the economic burden of glaucoma.

So far we know that the costs for glaucoma are continuously increasing (Dirani et al. [6]) and that medications are making up the largest amount of the direct costs (Olsen, Berdeaux et al [4]; Traverso et al. [8]: Varma et al. [25]) and also Töteborg-Harms et al. [9] confirmed that health care costs are continuously increasing which is also true for the cost of glaucoma diagnosis and treatment.

Now the question may arise about what possibilities are available in order to make the diagnosis and glaucoma more eﬃcient and therefore also more economic?

Töteborg-Harms et al. [9] were analyzing these questions in their literature review. They analyzed articles from four diﬀerent sections: costs of diagnostic tests, costs of the direct comparison between drugs or laser and conventional surgery, patient-related factors of costs and general aspects regarding the costs of glaucoma.

As well as Varma et al. [25] also Töteborg-Harms et al. [9] were stating that glaucoma causes direct as well as indirect costs.

Direct costs are the expenses for diagnostic tests, drugs, surgical treatment, physician and hospital visits and transportation and care costs.

Indirect costs consist of the lost productivity by the patient and his caregivers.

Töteborg-Harms et al. were criticizing that there is a lack of scientific articles on how to make glaucoma more cost-effective. But they found out that using Heidelberg retina tomography 2 (HRT II) instead of Glaucoma detection x (GDx) is more cost-effective and they suggested that telemedicine could offer some cost benefits compared to direct patient contact.

Additionally, comparing diﬀerent drugs can make the treatment more cost-eﬀective

according to the authors since generic drugs appeared to be four times cheaper than brand drugs and also it makes sense to compare diﬀerent formulations of a drug, for example, Latanoprost appeared to cause diﬀerent costs according to the size of the drop and the size of the bottle opening and the number of drops per bottle. Also overreacting can increase the cost since Töteborg-Harms et al. [9] found out that ocular hypertension, when it is

confirmed, needs not to be monitored more often than every two years in order to be eﬀective.

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They also assumed, that surgeries when compared to medications are likely to lower

treatment costs in the long term despite of the higher costs in the short term because also a big cost factor is the low adherence to the treatment plan of the patients, which brings me to the next section of this literature review which will focus on different studies about the patients adherence in glaucoma. Because even the best and most effective and economic treatment plan appears to be ineffective and uneconomic when it is not precisely followed by the patients.

3.4. Patients adherence

Fiscella et al. [24] suggested that in cost considerations for glaucoma also the

non-adherence of patients to their treatment should be included because it can also be a huge cost factor and economic burden.

But what are the reasons for non-adherence to the prescribed treatment regimen by the patients?

Tsai [15] was also asking himself this question and tried to identify the risk factors for the low adherence or non-adherence to topical glaucoma medications which are used by patients to reduce the intraocular pressure.

When one thinks first about glaucoma one merely thinks that it is a disease of the old and then considers that maybe reduced cognition or musculoskeletal problems may be the cause for low or non-adherence to the treatment. Also, Tsai [15] had this first thought but he found out that this is not the biggest risk factor for poor adherence. Medication costs, limited health insurance, disease severity and complicated dosing regimens play a much bigger role according to the author in low-adherence or non-adherence of a patient to his prescribed glaucoma treatment. Tsai [15] further stated that there is a connection between low medication adherence and low-adherence to following-up visits. It was further

mentioned by Tsai [15] that the communication between a doctor and a patient plays an important role in the adherence of a patient to the treatment regimen prescribed by his doctor.

Nordmann et al. [16] picked up on that suggestion and made suggestions on how a doctor can improve the adherence in his glaucoma patients.

Like Tsai [15] they also tried to understand the factors that lead to non-adherence and concluded that they could be either patient related like having doubt, being forgetful, being

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in denial or they can be environmental like high costs or lastly they can be due to the

prescribed treatment regimen like how often do patients have to refill their medications, how complex is the use of medications and are there any side eﬀects.

In addition to these reasons, Nordmann et al. [16] also mentioned that the relationship between a doctor and his patients may play an important role in the adherence to the prescribed treatment regimen.

They advise doctors to presume that patients have low-adherence to their treatment and then give them clear and precise information about the expected benefits of the treatment, the disease and its risk of progression when not following the prescribed treatment regimen. Additionally, doctors should prefer the use of the combined fixed treatment solutions in order to make the use easier and to increase the tolerance of the eye drops.

But what when costs are a factor of non-adherence how many doctors do even talk about that topic with their patients.

Slota et al. [17] were analyzing this questions by examining the oﬃce visits of glaucoma patients and came to the conclusion that in the majority of glaucoma oﬃce visits costs of the treatment were not discussed or an issue. They advised doctors to bring up that topic in order to overcome that barrier of non-adherence.

3.5. Is screening useful?

We know so far that most glaucoma cases are currently undiagnosed (Tuulonen, [1]) and that the costs of glaucoma are increasing with the severity of the disease (Traverso et al. [8]), so wouldn’t it be perfect to just introduce a general screening routine in order to decrease the number of undiagnosed cases and to start treatment sooner and wouldn’t that also simultaneously decrease the economic burden?

Unfortunately, it is not so easy.

In 2013 the U.S. Preventive Services Task Force (USPSTF) updated their recommendations on screening for glaucoma from 2004.

In their update, the USPSTF reviewed new evidence on the benefits and harms of screening for glaucoma and additionally of medical and surgical treatment of early glaucoma. They hereby merely focused on improved vision-related quality of life and reduced progression of

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early asymptomatic glaucoma to vision-related impairment. They also focused on evidence on the accuracy of glaucoma screening tests.

In their study, the USPSTF concluded that they found inadequate evidence on the accuracy of screening for primary open-angle glaucoma in adults since the evidence is limited by the lack of an established gold standard against which individual screening tests can be

compared. This means that there is no established commonly agreed on diagnostic principle upon which glaucoma can be diagnosed. Merely the current way of diagnosing primary open-angle glaucoma is based on a combination of tests showing characteristic

degenerative changes in the optic disc and defects in the visual field. Also, intraocular pressure was considered as an important factor in the diagnosis of glaucoma but now we do know that there are also many patients with primary open-angle glaucoma who have a normal intraocular pressure and that not all patients with an increased intraocular pressure will develop glaucoma. That means that only screening with tonometry is inadequate to detect all cases of primary open-angle glaucoma.

Also, the measurement of the visual field can be diﬃcult because the reliability of a single measurement can be low and several constant measurements are needed to establish the presence of defects.

A similar problem occurs with the evaluation of the optic disc because doctors have varying abilities on detecting glaucomatous progression of the optic disc by the use of tilted

ophthalmoscopy or slit lamp examination.

In conclusion, it can be said that the USPSTF found no direct evidence on the benefits of screening but they found convincing evidence that treatment of increased intraocular pressure and early glaucoma reduces the number of patients who develop visual field defects and that it decreases the number of patients whose visual field defects worsen. Furthermore, they concluded that since screening is associated with a risk for false-positive and false negative results, screening and treatment is also associated with the risk of over-diagnosis and over-treatment.

Moment et al. [11] also confirmed in their literature review that there is still a lack of a sensitive and specific screening test for glaucoma and suggested that more research is needed in order to understand glaucoma progression better which may enable us to find improved screening tests.

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In contrast to that Tuulonen [12] clearly suggests that screening is beneficial by being a cost-eﬀective strategy. She showed that by simulating an organized screening program by using Markov modelling in a population of 50-79 years at 5-year intervals.

In her results, she listed that 1 year of avoided visual disability by screening made up an amount of 32602 euro of incremental costs and the cost of one quality adjusted life year gained by screening was listed by her with 9023 euro.

3.6. Drug eﬀectiveness

After having reviewed the current literature about diagnosing and screening for glaucoma it is time to pay attention on how to actually be more eﬃcient when patients are already diagnosed with glaucoma.

We know so far that drugs make up the largest amount of the direct costs of glaucoma (Olsen et al. [4]; Traverso et al. [8]: Varma et al. [25]; Töteborg-Harms et al. [9]). So we should now analyze the literature on the eﬀectiveness of commonly prescribed drugs in order to evaluate if there is some potential to become more eﬃcient.

We know that there is no reversible treatment for glaucoma, that ocular hypertension is a risk factor for developing glaucoma and that all the currently available drugs for glaucoma can oﬀer is to reduce the intraocular pressure and thereby either reduce the risk of

developing glaucoma in patients who are at risk or to slow down the progression of glaucoma.

Li et al. [13] assessed the eﬀectiveness of first-line medications from four diﬀerent groups: beta-blockers, carbonic anhydrase inhibitors, alpha-2-adrenergic agonist and prostaglandin analogues for the treatment of primary open-angle glaucoma by comparing them with each other and a fifth placebo group over a period of three months.

They came to the conclusion that all of the 14 examined drugs from the four different groups of drugs were more effective in lowering the intraocular pressure than a placebo and out of the four groups of drugs, the class of prostaglandin drugs was the most efficacious and that drugs within a certain group had only little differences.

This confirms what was already stated by Trkulja [14] in 2014. He analyzed diﬀerent

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that the prostaglandin analogues were the group with the highest efficacy and out of this group Latanoprost was the best drug in terms of efficacy and especially tolerability since the efficacy in other drugs of this group such as Travoprost and Bimatoprost were the same but they caused more side effects.

Due to these result, he suggested that prostaglandins should be the general first-line treatment for glaucoma and only in the case when its use is contraindicated other drugs from the other three different groups should be considered, which all offer the same efficacy.

3.7. Ocular hypertension

Ocular hypertension increases significantly the risk of developing glaucoma and most patients with glaucoma present with ocular hypertension but it is also important to know that not all glaucoma patients necessarily need to have ocular hypertension, as it is the case in patients with normal tension glaucoma.

But what is the best practice of dealing with ocular hypertension, when should treatment be started, upon what degree of ocular hypertension, or is it perhaps more eﬀective to just initiate treatment when glaucoma is been diagnosed?

This was investigated by van Gestel et al. [20]. In their study, they focused on the question if either starting treatment immediately after the diagnosis of ocular hypertension or waiting with the beginning of treatment until ocular hypertension turns into glaucoma (watchful waiting) is more eﬀective in the long term.

They simulated each patient according to both strategies, either the direct treatment strategy or the watchful waiting strategy. They also collected from each patient the clinical outcomes, meaning whether the patient converted to primary open-angle glaucoma, progressed to blindness, what procedures were applied and also the average intraocular pressure during the simulation of the patients.

In the results of their simulations, they estimated that patients with ocular hypertension and are directly treated conversed less likely to glaucoma compared to patients who were only treated later. More than 50% of the patients who were not treated for ocular hypertension converted to primary open angle glaucoma in their lifetime, with direct treatment only about a third of the patients conversed to primary open angle glaucoma in their lifetime. Also, the occurrence of blindness was less likely in that strategy.

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In terms of economics, the use of medications in the direct treatment strategy was higher but the incidence of laser therapy and surgery was lower.

It was further stated that also the time interval of such a study is important because if you only analyze the first ten years then the direct treatment strategy is more expensive but in the long term, it is more cost-eﬀective and amounts to a cost reduction of 649 euro per patient compared to watchful waiting.

In conclusion, it can be said that according to this study the direct treatment strategy of ocular hypertension is a strategy with better treatment outcomes and is additionally in the long term more cost-eﬀective than watchful waiting.

This was also mentioned by Tuulonen [18] who was citing a study in her literature review that suggested that treating all intraocular pressures above 21mmHg would be cost-saving. And also Burr et al. [19] found out in their broad study about determining effective and efficient monitoring criteria for ocular hypertension that the „treat all patients immediately“ strategy is the least costly and therefore most efficient strategy and that there is no benefit from too intensive monitoring.

But what might be too intensive monitoring and what is the most eﬃcient number of monitoring while still being eﬀective in treating patients with glaucoma?

3.8. Treatment and follow up

Hernandez et al. [21] compared 5 diﬀerent monitoring practices.

1. Treating ocular hypertension upon diagnosis with minimal monitoring 2. Biennial monitoring with primary and secondary care

3. Treatment if baseline predicted 5-year glaucoma risk is greater than 6%

4. Monitoring and treating aligned to National Institute of Health and Care excellence glaucoma guidance either conservative or intensive which mainly focuses on the

conversion from ocular hypertension to chronic open-angle glaucoma and if there is no detected or uncertain conversion monitoring after a period of 1 or 4 months is indicated and if there is not conversion only reassessment is indicated in an interval between 18 and 24 months.

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This broad comparative study was performed on 10000 patients with ocular hypertension with a mean intraocular pressure of 24,9 mmHg.

They also confirmed, as already van Gestel et al. [20] and Burr et al. [19] did mention, that treating patients with ocular hypertension immediately right from the diagnosis is the least costly but they additionally found out that it is also the least eﬀective in avoiding that ocular hypertension turns into glaucoma and progresses.

The most eﬀective way of preventing the conversion to glaucoma from ocular hypertension was according to the authors intensive monitoring following the national institute for health and care excellence glaucoma guidance but it was also the most costly. And biennial monitoring was in terms of cost-eﬀectiveness in between these two other methods. It was more costly than treating at diagnosis but less costly than the intensive monitoring.

According to this, it was concluded by the authors that monitoring of ocular hypertension more frequently than every 2 years is unlikely to be eﬃcient and therefore monitoring every 2 years was predicted to be the most cost-eﬀective frequency of monitoring.

Monitoring ocular hypertension is not the only way of monitoring in patients with glaucoma. Once glaucoma was diagnosed also the visual field is occasionally monitored in order to evaluate how the disease progresses.

Boodhna et al. [22] were analyzing a hypothesis which stated that more frequent visual field examinations during the follow up after the diagnosis of primary open-angle glaucoma may be more eﬀective.

The current practice of visual field monitoring in England is annual visual field testing and the author proposed a practice in which three visual field tests per year within the first 2 years after the diagnosis of chronic open-angle glaucoma are performed.

That hypothesis was tested with the use of a Markov model and that model confirmed that in the early stages of follow-up an increased number of visual field monitoring can be cost-eﬀective.

In conclusion, it can be said that till today scientist and doctors are still not hundred per cent sure what is the most eﬀective way of monitoring because to say it with Tuulonen’s words „there is still no precise understanding if we are actually doing the right things in everyday practices“[18]. That is also why Boodhna et al. [22] requested further studies in order to understand the practice of various monitoring schemes better.

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3.9. Conclusion

It is a fact that the global economic burden of glaucoma is rising and will only continue to rise. Our literature confirmed the current scientific agreement that more research on the field of glaucoma and its economic aspects is needed in order to understand the disease better, which would perhaps enable us to introduce new diagnostic test so that at one point we will have a gold standard diagnostic procedure which will make screening possible. But while we are waiting for such scientific breakthroughs our literature review also showed that there are plenty of measures that we can already apply today, starting with treating patients with ocular hypertension immediately instead of performing watchful waiting, informing the patients precisely about the use of the drugs and also discussing with them the impact of the disease and the costs in order to increase the patients adherence.

Furthermore, we should consider using generic drugs and drugs that are more eﬃcient than others and trying to avoid treatment changes by carefully choosing an eﬀective treatment upon diagnosis.

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CHAPTER 4: RESEARCH METHODOLOGY AND METHODS

Our study is a cross-sectional survey conducted at the Lithuanian University of Health Sciences. Our study was carried out during January and February of 2019 among glaucoma patients of the Eye Clinic of LSMU Kaunas clinics of the Lithuanian University of Health Sciences. The participants were answering an original questionnaire that was created and adapted to the main goals of our research according to publications on this important topic (56,57). The study population and sample size of our study consists of 50 patients with a diagnosis of glaucoma for at least 5 years. The sample size was further subdivided into 30 patients who were receiving conservative treatment and 20 patients who received surgical treatment for their glaucoma.

All the participants gave full consent before they were answering the questions.

The patients who received conservative treatment were questioned in the Eye Clinic of LSMU Kaunas clinics before or after they visited their ophthalmologist for an appointment. The patients who received surgical treatment were questioned in their wards after they received surgical treatment.

To all of the participants, the purpose of the questionnaire was explained as well as their participation was entirely voluntary and their answers will be treated confidentially and only published anonymously.

The participants were given all the time needed to answer the questionnaire.

Our questionnaire focused mainly on the economic factors in the therapy of glaucoma and the perceived quality of life of the patients and the reasons that may have diminished it. Firstly, the participants were asked about their age, gender and for how many years they are already suﬀering from glaucoma. The following questions then focused on their treatment and how it aﬀects their quality of life by asking them about the number of medications they are currently using, what kind of medications they are using and if adhering to the

prescribed treatment is convenient to them or not and if they may suﬀer from any side eﬀects of the prescribed treatment.

The next part of the questions of the self-created questionnaire focused on the economic aspects of their treatment by asking the participants about, the number of the drugs they

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were taking, the frequency of their follow-up visits, the costs of their treatment and if they mark a financial burden.

Furthermore, the participants were also asked if they would consider a surgical option if it would free them from taking eye drops and if they have already undergone surgery they were asked if their quality of life decreased or increased after the surgery.

The participants were also asked about any concomitant diseases like hypertension, atherosclerosis and diabetes which are risk factors for the development of glaucoma. The next questions focused on how often the patient are receiving a follow-up in their

treatment and on the personal and economic problems that go in hand with attending these follow-ups like having diﬃculties to come to the hospital, needing an escort to come to the hospital, having to take time oﬀ from work in order to attend the follow-ups and the costs of transportation.

The last questions focused on the perceived quality of life of the patients by letting them judge their quality of life on a scale from 1 to 10, where 1 marks the lowest possible quality of life and 10 the highest, and asking them about changes in their quality of life since the diagnosis of glaucoma and in the case it worsened about the factors that contributed to the worsening like not being able to do certain activities that were normal to them, having problems with following the prescribed treatment, suﬀering from side eﬀect, or

psychological problems due to the diagnosis of glaucoma.

Lastly, the participants were asked if they are not able to do the following activities anymore due to their glaucoma disease: driving, reading newspapers or books, recognizing faces, seeing in the dark and crossing streets, which also may contribute to a decreased

perception in the quality of life.

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CHAPTER 5: RESULTS AND THEIR DISCUSSION

5.1. DESCRIPTION OF THE PARTICIPANTS

a. Age of the participants

50 patients (n=50) diagnosed with glaucoma for a period of at least 5 years were included in our study and filled out the self-created questionnaire about their glaucoma in the presence of the researcher. 30 out of these 50 patients were receiving conservative treatment for their glaucoma and 20 patients received surgical treatment.

The average age of the participants was 67,6 years (SD=10,7). The youngest participant was 29 years old and the oldest participant was 84 years old. The age of the participants was also divided into certain age groups ranging from 25-39 years, 40-49 years, 50-59 years, 60-69 years, 70-79 years and 80 years and older as indicated in Table 1. 43 participants (86%) of all participants were 60 years and older. 22 Participants (44%) of all participants were in their sixties, 17 participants (34%) of all participants in their seventies, 4 participants (8%) of all participants in their eighties and only 7 participants (14 %) of all participants were younger than sixty, three participants (6%) were in their fifties, three participants (6%) in their forties and only one participant (2 %) was in his or her twenties or thirties as shown in Table 1 and 2.

The average age of conservatively treated patients was 68,5 years (SD=10,5) The youngest conservatively treated participant was 45 years old and the oldest conservatively treated patient was 84 years old.

The biggest amount of conservatively treated patients (n=12, 40%) were between 60 and 69 years old, 10 patients (33,3%) were between 70 and 79 years old and only 4 conservatively treated patients (13,3%) were 80 years or older. And respectively also only 4 conservatively treated patients (13,3%) were younger than 60 years old.

Surgically treated patients whereas were on average 66 years old (SD=11,2). Therefore, they were on average 2,5 years younger than conservatively treated patients. The youngest surgically treated patient was 29 years old and the oldest surgically treated patient was 78 years old.

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As for conservatively treated patients, the largest amount of surgically treated patients (n=10, 50%) was between 60- 69 years old. Only 3 surgically treated patients (20%) were younger than 60 and 7 surgically treated patients (35%) were between 70 and 79 years old.

To compare if the age between conservatively treated patients and surgically treated patients was significantly diﬀerent an H0 hypothesis was formulated which states that the treatment method was not related to the age of the patient.

H1 whereas states that treatment method was related to the age of the participant. To prove which of these hypothesizes is correct an independent-Samples T-test was

performed. The p-Value as shown in Table 2 of the independent Sample T-Test was p=0,452, therefore p>0,05, which means that the H0 Hypothesis could not be rejected, which means that the average age did not depend on the treatment method. The diﬀerences in the

average age between these two groups were not statistically significant.

Table 1: Age Groups of the Participants

b. Gender

18 participants (36%) were male and 32 participants (64%) were female.

The majority of the conservatively treated patients were female (n=22, 73,3%). Only a bit more than a quarter of the conservatively treated patients were male (n=8, 26,7%.

In comparison, exactly half of the surgically treated patients were male (n=10, 50%) and half female (n=10, 50%) as shown in Table 2.

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To compare if the gender between conservatively treated patients and surgically treated patients was related to the respective treatment method, another H0 hypothesis was formulated, which states that the treatment method was not related to the gender. H1 whereas states that the treatment method was related to the gender.

To prove which of these hypothesizes is correct a Chi-Square Test was performed. The p-Value as shown in Table 2 of the Pearson Chi-Square Test was 0,226, therefore p>0,005, which means that the H0 hypothesis could not be rejected, which means that the gender was not related to the treatment method. The diﬀerences in the frequencies of gender in the two diﬀerent treatment methods were not statistically significant.

Chi-Square test result (27)=32.153 p=0,226.

c. Time span since the diagnosis of glaucoma

The average time span since the diagnosis of glaucoma of the participants was 10,5 years (SD=4,9). The shortest time span since the diagnosis of glaucoma was 5 years and the longest time span was 25 years.

Also, for the time span since the diagnosis of glaucoma certain groups were formed for the statistical analysis, namely 5-9 years, 10-14 years, 15-19 years, 20-24 years and 25 years and more. Most frequently (23, 46%) participants were in the first group of 5-9 years since the diagnosis, 17 participants (34%) were in the second group of 10-14 years since the diagnosis, 7 participants (14%) were in the third group of 15-19 years since the diagnosis, 2 participants (4%) were in the fourth group of 20-24 years since the diagnosis and only one participant (2%) was diagnosed with glaucoma 25 years ago as shown in Table 2.

The average time span since the diagnosis of glaucoma for conservatively treated patients was 10,9 years (SD=5,1) The shortest time span for conservatively treated patients was 5 years and the longest time span was 25 years.

Almost half of the conservatively treated patients (n=13, 43,3%) were diagnosed with glaucoma 5-9 years ago. 9 conservatively treated patients (30%) were diagnosed with glaucoma 10-14 years ago, 6 conservatively treated patients (20%) were diagnosed with glaucoma 15-19 years ago and 2 patients (6,6%) were diagnosed with glaucoma more than 20 years ago as shown in Table 2.

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The average time span since the diagnosis of glaucoma for surgically treated patients was 9,9 years (SD=4,5), thereby it was only 1 year shorter than the average time span for conservatively treated patients.

The shortest time span for surgically treated patients was 5 years and the longest time span was 22 years, almost equal to conservatively treated patients.

Also, surgically treated patients have been most frequently (n=10, 50%) diagnosed with glaucoma 5-9 years ago. 8 surgically treated patients (40%) have been diagnosed with glaucoma 10-14 years ago, and only 2 surgically treated patients (10%) have been diagnosed with glaucoma more than 15 years ago as shown in Table 2.

To analyze if the time span since the diagnosis of glaucoma diﬀered between conservatively treated patients and surgically treated patients an independent Sample T-Test was

performed.

H0 states that the time spend does since the diagnosis of glaucoma did not diﬀer between conservatively and surgically treated patients.

H1 states that the time span since the diagnosis of glaucoma diﬀered between conservatively and surgically treated patient.

The result of the independent Samples T-Test was as shown in Table 2 (48)=0,305, p=0,584, p>0,05.

Therefore the H0 hypothesis could not be rejected and it can be said that there was no statistically significant diﬀerence in the time span since the diagnosis of glaucoma between conservatively and surgically treated patients.

d. The average amount of antiglaucoma drugs

The participants were using an average amount of 1,9 drugs (SD=1,1) for their glaucoma. 2 Participants (4%) were not using any drugs for their glaucoma. 17 participants (34%) were using one drug, 18 participants (36%) were using two drugs, 9 participants (18%) were using 3 drugs, 3 participants (6%) were using 4 drugs and only 1 participant (2%) was using 5 drugs as shown in Table 2.

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Conservatively treated patients took on average 1,7 (SD=0,7) antiglaucoma drugs. The lowest number of drugs a conservatively treated patient was taking was 1 and the highest number of drugs a conservatively treated patient took was 3 as shown in Table 2.

Surgically treated patients took on average 2,4 (SD=1,4) drugs for their glaucoma and the lowest number of drugs that a surgically treated patient was taking was none and the highest amount a surgically patient was taking were 5 as shown in Table 2.

To analyze if surgically treated patients took on average more drugs than conservatively treated patients an independent Sample T-Test was performed.

H0 states that the number of drugs a patient was taking did not depend on the treatment method.

H1 states that the average number of drugs depended on the treatment method, so in this case, surgically treated patients were taking more drugs than conservatively treated

patients.

The result of the independent Samples T-Test was as shown in Table 2 (48)=14.790 p=0,024. p<0,05.

Therefore the H0 hypothesis was rejected and it can be said that the there is a correlation between the treatment method and the average number of drugs a patient was taking and that this correlation was statistically significant, so surgically treated patients were taking on average more drugs than conservatively treated patients.

e. Groups of antiglaucoma drugs

The participants were also asked what antiglaucoma drugs they were taking. Their answers were then for a better statistical analysis pooled to the following antiglaucoma drug classes: alpha 2 agonists, prostaglandins analogues, beta blockers, and carbonic anhydrase

inhibitors.

Not all participants were indicating which drugs they were taking, one participant (2%) was not taking any drugs and 11 (22%) participants did not answer this question.

Out of the 38 participants that answered this question, 30 participants (78,9%) were taking prostaglandins analogues, 22 participants (57,9%) were taking beta-blockers, 20

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participants (52,6%) were taking carbonic anhydrase inhibitors and only 11 participants (28,9%) were taking alpha 2 agonists as shown in Table 2.

So it can be said that most participants (almost 80%) who answered that question were taking prostaglandin analogues and around half of the participants were taking beta-blockers and/ or carbonic anhydrase inhibitor and a bit less than a third of the participants were taking alpha 2 agonists.

21 out of 30 (70%) conservatively treated patients were reporting what kind of drugs they were taking for their glaucoma.

The most often reported class of antiglaucoma drugs by conservatively treated patients were prostaglandin analogues. 17 conservatively treated patients (81%) were taking drugs of this group. The second most often reported class of antiglaucoma drugs by conservatively treated patients were beta blockers, 13 conservatively treated patients (51,9%) were taking drugs of this group.  

The third most often reported class of antiglaucoma drugs by conservatively treated patients were carbonic anhydrase inhibitors, 9 conservatively treated patients (42,9%) took drugs of this group and the least commonly reported group of drugs by conservatively treated patients were alpha 2 agonists, only 3 conservatively treated patients (14,3) took drugs of this group as shown in Table 2.

17 out of 20 (85%) surgically treated patients were reporting what kind of drugs they were taking for their glaucoma.

The most often response by surgically treated patients were also prostaglandin analogues, 13 (76,5%) surgically treated patients were taking drugs of this group. The second most commonly reported class of drug by surgically treated patients were carbonic anhydrase inhibitors, 11(64,7%) surgically treated patients were taking drugs of this group, followed by beta-blockers, 9 (52,9%) surgically treated patients were taking drugs of this group and the least mentioned group of antiglaucoma drugs by surgically treated patients were alpha 2 agonists, 8 (47,1%) surgically treated patients were taking drugs of this group as shown in Table 2.

It can be said that with the exception of the prostaglandins analogues, which also represents the first line treatment in glaucoma, the classes of drugs were almost equally distributed between surgically treated patients. This can not be said about conservatively

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treated patients because alpha 2 agonists were highly underrepresented in conservatively treated patients.

To analyze if there is a statistically significant diﬀerence between conservatively and surgically treated patients in the types of drugs they were taking a Chi-Square Test was performed.

H0 states that conservatively and surgically treated patients were not taking diﬀerent classes of drugs for their glaucoma.

H1 states that conservatively and surgically treated patients were taking diﬀerent classes of drugs for their glaucoma.

The result of the Chi-Square Test was as shown in Table 2 (4)=7,128 p=0,129. p>0,05. Therefore the H0 hypothesis could not be rejected and it can be said that there was no statistically significant diﬀerence in the classes of drugs conservatively and surgically treated patients were taking.

f. Concomitant diseases

47 out of 50 (94%) participants were reporting if they also receive concomitant therapy for any other disease or diseases.

The most often response of all participants was that they were concomitantly receiving treatment for hypertension (n=23, 49%), followed by the response that they do not receive any concomitant treatment for any other disease (n=21, 44,7%), the response that they are concomitantly receiving treatment for atherosclerosis (n=10, 21%) and the response that they are receiving concomitant therapy for diabetes mellitus (n=2, 4%) as shown in Table 2.

28 out of 30 (93,3%) conservatively treated patients reported if they also receive concomitant therapy for any other disease or diseases.

The most common response of conservatively treated patients was that they do not receive any treatment for any other diseases, 13 (46,4%) of the conservatively treated patients gave that answer. It is followed by the response that the patients are concomitantly also receiving treatment for hypertension, 11 (39,3%) of the conservatively treated patients gave that answer. 7 (25%) conservatively treated patients were receiving treatment for atherosclerosis and only 1 (3,6%) conservatively treated patient received treatment for diabetes mellitus.

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19 out of 20 (95%) surgically treated patients reported if they are also receiving concomitant therapy for any other diseases or diseases

The majority of surgically treated patients (n=12, 63,3%) were receiving treatment for hypertension. 8 (42,1%) surgically treated patients reported that they do not receive any treatment for any other disease.

Only 3 (15,8%) surgically treated patients received treatment for atherosclerosis and also only 1 (5,3%) patient received treatment for diabetes mellitus as shown in Table 2.

Chi-Square Test was performed to analyze if there was a statistically significant diﬀerence in the distribution of the concomitant diseases between conservatively and surgically treated patients.

H0 states that there was no statistical difference in the distribution of the concomitant diseases between conservatively and surgically treated patients. Therefore conservatively and surgically treated patients would have not suffered from different concomitant diseases. H1 states that there was a statistical difference in the distribution of the concomitant

diseases between conservatively and surgically treated patients, which would mean that conservatively and surgically treated patients would have suﬀered from diﬀerent

concomitant diseases.

The result of the Chi-Square Test was as shown in Table 2 (4)=3,320 p=0,506, p>0,05.

Therefore the H0 hypothesis could not be rejected and it can be said that conservatively and surgically treated patients were suﬀering from diﬀerent concomitant diseases.

g. The frequency of follow-up visits

Almost half of the respondents (n=23, 46%) were visiting their ophthalmologist for follow-ups every 6 months. 15 respondents (30%) were having follow-follow-ups every 3 months, 7 respondents (14%) had follow-ups every month and 5 respondents (10%) were visiting their ophthalmologist less than every 6 months as shown in Table 2.

Most conservatively treated patients (n=19, 63,3%) were visiting their ophthalmologist for follow-up every 6 months. 5 (16,7%) conservatively treated patients were visiting their

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ophthalmologist even less than every 6 months and respectively 3 (10%) conservatively treated patients were visiting their ophthalmologist every 3 months and every month as shown in Table 2.

Most surgically treated patients whereas were visiting their ophthalmologist every 3 months (n=12, 60%). And only respectively 4 (20%) surgically treated patients were visiting their ophthalmologist for follow-up every 6 months, respectively every month. None of the surgically treated patients was visiting their ophthalmologist less than every 6 months as shown in Table 2.

To analyze if the diﬀerences in the frequency of follow-up visits between conservatively and surgically treated patients were statistically significant a Chi-Square Test was performed. H0 says that the interval of the follow-up visits did not depend on the treatment method. H1 says that the interval of the follow-up visits depended on the treatment method, that it was related to the treatment method.

The Chi-Square Test result was as shown in Table 2 (3)=19.089 p=0,000. p<0,05. Therefore the H0 hypothesis could be rejected and it can be said that the interval of the follow-up visits and the treatment method were statistically significantly related to each other,

surgically treated patients were visiting their ophthalmologist more often than conservatively treated patients.

Table 2: Sociodemographic and general parameters of the study population Sociodemo-graphic and general para-meters of the study popula-tion Conservatively treated pati-ents results n=30 Surgically treated pati-ents results n=20 All patients n=50 p-Values p= Age years (mean +- SD) 68,5 +- 10,5 66 +- 11,2 67,6 +- 10,7 0,452 Gender: - male - female 8 (26,7%) 22 (73,3%) 10 (50%) 10 (50%) 18 (36%) 32 (64%) 0,226

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Time span sin-ce the dx in years (mean +-SD)

10,9 +- 5,1 9,9 +- 4,5 10,5 +- 4,9 0,584

Time span sin-ce the dx in years groups: 5-9 years 10-14 years 15-19 years 20-24 years =/> 25 years 13 (43,3%) 9 (30%) 6 (20%) 1 (3,3%) 1 (3,3%) 10 (50%) 8 (40%) 1 (5%) 1 (5%) 0 23 (46%) 17 (34%) 7 (14%) 2 (4%) 1 (2%) Amount of anti glaucoma drugs (mean +-SD) 1,7 +- 0,7 2,4 +- 1,4 1,9 +- 1,1 0,024 Classes of anti glaucoma drugs: - Prostaglan-din analo-gues - Beta Blo-ckers - Carbonic an-hydrase inhi-bitors - Alpha 2 ago-nists 17 (81%) 13 (61,9%) 9 (42,9%) 3 (7,1%) 13 (76,5%) 9 (52,9%) 11 (64,7%) 8 (47,1%) 30 (78%) 22 (57,9%) 20 (52,6%) 11 (28,9%) 0,129 Concomitant diseases: - Hypertensi-on - Atheroscle-rosis - Diabetes mellitus - None 11 (39,3%) 7 (25%) 1 (3,6%) 13 (43,3%) 12 (63,3%) 3 (15,%) 1 (5,3%) 8 (42,1%) 23 (49%) 10 (21%) 2 (4%) 21 (44,7%) 0,506 Sociodemo-graphic and general para-meters of the study popula-tion Conservatively treated pati-ents results n=30 Surgically treated pati-ents results n=20 All patients n=50 p-Values p=