This is an author version of the contribution published on:
Questa è la versione dell’autore dell’opera:
[Scand J Gastroenterol., 50(11), 2015, 10.3109/00365521.2015.1050691.]
ovvero [Greco A, Caviglia GP, Brignolo P, Ribaldone DG, Reggiani S, Sguazzini
C, Smedile A, Pellicano R, Resegotti A, Astegiano M, Bresso F., 50, Taylor &
Francis, 2015, pagg.1376-1381]
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Glucose breath test and Crohn’s disease: diagnosis of small intestinal
bacterial overgrowth and evaluation of therapeutic response
Short title: Glucose Breath Test and Crohn’s Disease
ANNA GRECO 1*, GIAN PAOLO CAVIGLIA 2*, PAOLA BRIGNOLO 1, DAVIDE
GIUSEPPE RIBALDONE 1, STEFANIA REGGIANI 1, CARLO SGUAZZINI 1,
ANTONINA SMEDILE 2, RINALDO PELLICANO 1, ANDREA RESEGOTTI 1, MARCO
ASTEGIANO 1, FRANCESCA BRESSO 3
1 Department of Gastroenterology and Hepatology, Città della Salute e della Scienza Hospital, Via Cavour 31, 10123, Turin, Italy. Tel.: +390116333565; fax: +390116333623, 2 Department of Medical Sciences, University of Turin, Via San Massimo 24, 10123, Turin, Italy. Tel.: +390116333922; fax: +39011633397, 3 Gastrocentrum medicin, Karolinska University Hospital, Hälsovag 7-9, 14183 Stockholm, Sweden. Tel.: +46 8 6089143; fax: +46 8 7745538
Abstract
Objective. Small intestinal bacterial overgrowth (SIBO) is characterized by an abnormal proliferation of bacterial species in the small bowel. It has been shown that patients with Crohn’s disease (CD) have an higher risk of SIBO development. The aim of the present study was to investigate SIBO prevalence in CD patients, possible clinical predictors of SIBO development and response to antibiotic therapy. Material and Methods. Sixty-height patients (42M, 26F; mean age 49.3±12.8 years) with CD reporting abdominal complaints were prospectively evaluated for SIBO with H2/CH4 glucose breath test (GBT).
Results. Of the 68 patients enrolled, 18 (26.5%) tested positive for SIBO. Patients with SIBO exhibited increased stool frequency and significant reduction of stool solidity
(p=0.014), were older than patients tested negative to GBT (54.3±13.0 years vs. 47.5 ± 12.3 years, p=0.049), reported a longer history of CD (21.2±10.3 years vs. 15.7±10.2 years, p=0.031) and showed a significant higher frequency of prior surgery (p=0.001), revealing an association of number of surgical procedures (OR=2.8315, 95% CI 1.1525-6.9569, p=0.023) with SIBO. Breath test normalization occurred in 13/15 patients evaluated after antibiotic and probiotic therapy. Although vitamin B12 levels were lower in patients with SIBO (p=0.045) and a significant improvement was found after treatment (p=0.011), this could be due to the heterogeneity, regarding vitamin B12 treatment, in our cohort.
Conclusion. SIBO is a frequent but underestimated condition in CD, which often mimics acute flare, effectively identified with GBT and could be treated with a combined antibiotic and probiotic therapy.
Author for corresponce: Anna Greco, MD, Department of Gastroenterology and
Hepatology, Città della Salute e della Scienza Hospital, Via Cavour 31, 10123, Turin, Italy. Tel.: +390116333565; fax: +390116333623. E-mail address: [email protected]
Introduction
Small intestinal bacterial overgrowth (SIBO) is a clinical syndrome characterized by an increased number of colonic-type-bacteria in the small bowel, exceeding 105 organism/mL
[1,2]. In physiologic conditions, symbiotic bacteria are compartmentalized to the distal gut thanks to ileocecal valve, intestinal peristaltic activity, antibacterial pancreatic and bile secretions, and several factors that inhibit bacterial adhesion to the epithelium including epithelial desquamation, intact mucus layer and secretory IgA production [3]. For these reasons, patients with impaired anatomic or functional factors secondary to inflammatory bowel diseases such as Crohn’s disease (CD) may exhibit a predisposition to SIBO [4]. Moreover, patients with CD who have experienced single or multiple bowel resections are more likely to develop SIBO [5].
As a consequence of SIBO, patients experience maldigestion and reduction of intestinal absorption with a variability of manifestations affected also by the underlying clinical condition and the extent of intestinal tract involved [6]. The most common
symptoms of SIBO include diarrhea, abdominal pain, bloating, higher stool frequency and looser stool forms which did not differ significantly from symptoms attributable to the inflammatory condition CD-related [7,8]. These aspects have an important clinical impact because of SIBO can be treated with a short course of antibiotic therapy whereas a relapse of CD activity requires anti-inflammatory treatment [9].
The aim of the present study is to investigate the prevalence of SIBO in patients with CD, the possible clinical predictors of SIBO development in such patients with or without a history of previous abdominal surgery, and the response to antibiotic therapy.
Methods
Patients
A total of 70 outpatients affected by Crohn’s disease addressed to the Division of Gastroenterology and Hepatology of Città della Salute e della Scienza Hospital of Turin were approached between April 2013 and May 2014.
A full medical history was obtained from all patients and a physical examination was performed. All patients underwent hydrogen (H2)/methane (CH4) Glucose Breath Test
(GBT) according to Rome Consensus Conference to achieve SIBO diagnosis [2].
Criteria for eligibility included: CD diagnosed by internationally accepted criteria [10], ileal/ileocolonic or colonic disease localization, both positive and negative history of previous surgery, clinical symptoms characterized by diarrhea (more than three bowel movements per day), meteorism and/or abdominal pain. Exclusion criteria were: use of antibiotics, pro-kinetics, therapy with probiotics, history of bowel preparation for
colonoscopy within four weeks preceding study inclusion, endoscopic evidence or clinical suspect of strictures and fistulas. Inflammatory biochemical and fecal tests (white blood cell [WBC], C-reactive protein [CRP], fecal calprotectin [FC]) and when necessary instrumental examinations were performed to exclude CD relapse and complications.
The study protocol was conformed to the guidelines of the Declaration of Helsinki and was approved by our Institutional Ethics Committee. All patients gave their written informed consent prior to recruitment.
All patients were instructed to eat a low fiber and carbohydrate restricted dinner on the day before GBT, to be fasting for at least 12 hours; smoking and physical exercise were not allowed for 12 hours before and during the test. Moreover, before the test, subjects were asked to brush their teeth and rinse out their mouth with an antiseptic mouth wash, in order to prevent an early hydrogen peak due to the action of the oral bacteria on test sugars. A fasting glucose blood test and a basal breath sample were collected immediately before glucose ingestion. Then, a dose of 75g of glucose in 150 mL of water was administered and breath samples were collected every 30 minutes for 3 hours. Breath concentration of H2 and
CH4 were immediately analyzed by gas chromatography using SC Microlyzer (QuinTron
Instrument Co., Milwaukee, WI, USA). The results were given as parts per million (ppm). An increased of breath concentration of H2 and/or CH4 ≥12 ppm in at least 3 readings over
baseline value was defined as SIBO [2].
Statistical analysis
Values were expressed as median and ranges or mean ± standard deviation (SD). Kruskal-Wallis and Fisher’s exact test were performed to analyze nonparametric continuous and categorical data, respectively. Chi-squaretest for trend was performed to analyzed contingency tables with 2 columns and 3 or more rows. The odds ratios (OR) and 95% confidence intervals (CI) of the variables associated with the diagnosis of SIBO were estimated using univariate and multivariate logistic regression models adjusting for age and gender. Regarding analysis of data before and after therapy, McNemar’s test and a paired Student’s t-test were used to compare frequencies of categorical variables and means of continuous variables, respectively. For all analysis, a p-value <0.05 was considered
statistically significant. All statistical analyses were performed using Med Calc software, version 9.2.1.0.
Results
Sixty eight out of 70 subjects fulfilled inclusion criteria and were enrolled in the study. Two patients refused to participate. Demographic, clinical and biochemical characteristics of the patients are reported in Table I and Table II.
The diagnosis of SIBO was made on the basis of GBT results. Of the 68 patients enrolled in this study, 18 (26.5%) tested positive for SIBO. H2 and CH4 producers were 17
and 1 respectively. Regarding demographic characteristics, patients with a diagnosis of SIBO were older (p=0.049) than patients tested negative to GBT, whereas no statistically significant differences were found in sex distribution (p=0.267).
With respect to the underlying CD, patients with SIBO had a longer history of disease (21.2 ± 10.3 years vs. 15.7 ± 10.2 years, p=0.031).
Of the 68 included patients, 58 (85%) had history of previous abdominal surgery, but no differences were found regarding the site of previous abdominal surgery (p=0.373). However, a trend towards higher extent of bowel resection was found (ileocecal resection, p=0.061; and ileocolon resection, p=0.073). Conversely, patients with SIBO showed a significant higher frequency of prior surgery procedures (p=0.001) and of 18 patients tested positive for SIBO, 17 (94,5%) had history of previous abdominal surgery.
All symptoms (Table II) reported were comparable among patients with and without SIBO. The daily stool frequency did not differ among patients with or without SIBO, while patients with SIBO showed a trend towards looser stool forms (p=0.057).
Regarding laboratory parameters, as expected, lower values of vitamin B12 were found among patients with SIBO (p=0.045).
Logistic regression analysis revealed a positive significant association of previous ileocolon resection (OR=4.0303, 95% CI 1.0040-16.1790, p=0.049) and number of surgical procedures (OR=3.2934, 95% CI 1.4515-7.4725, p=0.004) with SIBO. Nevertheless, in a multivariate logistic regression model adjusted for age and gender, only the number of prior surgical procedures (OR=2.8315, 95% CI 1.1525-6.9569, p=0.023) remained significantly and independently associated to the diagnosis of SIBO (Table III).
Patients with evidence of SIBO were treated with broad-spectrum antibiotics for 1 month and probiotics for the following 2 months: it was possible to evaluate treatment response in 15 out of 18 patients because 2 out of 18 were lost to follow-up and 1 out of 18 had CD relapse. In detail, 9 patients received ciprofloxacin 500 mg/day orally for 1 month, 4 patients received metronidazole 750 mg/day orally for 1 month and 2 patients were treated with rifaximin 1200 mg/day orally for 1 month. All patients received, at the end of antibiotic therapy, probiotics containing Lactobacillus casei DG (not less than 7595 billion of living cell per 100g of product) (Enterolactis® Plus, SOFAR) for the following 2 months.
GBT was repeated 4 month later the start of the antibiotic and probiotic therapy. GBT normalization occurred in 13 out 15 patients. One non responder patient treated with ciprofloxacin had GBT normalization following a second identical treatment regimen. Symptoms and biochemical parameters of the 13 patients that reported GBT normalization after antibiotic and probiotic therapy are reported in Table IV. Regarding symptoms no significant statistical improvement was found, whereas, among biochemical parameters, Vitamin B12 levels after antibiotic and probiotic treatment increased significantly (249 ± 147 pg/mL vs. 331 ± 160 pg/mL, p=0.011, in pre-treatment and post-treatment,
Discussion
In the present study, we investigated the prevalence and possible clinical predictors of SIBO in patients with CD. We observed that patients with increased breath concentration of H2 and/or CH4 were 18 out of 68 (26.5%) of the patients with CD tested. This figure is in
agreement with previous studies in which a prevalence ranging from 23% to 25% was found, although these studies included different proportions of patients who underwent previous surgeries and employed different diagnostic methods for SIBO [7,9,11].
Age appears to be a predisposing factor to SIBO. According to previous reports, we found that patients with SIBO are older (54.3 ± 13.0 years vs. 47.5 ± 12.3 years, p=0.049) [1,12]. Moreover, considering the underlying CD, patients who developed SIBO had a longer disease duration (21.2 ± 10.3 years vs. 15.7 ± 10.2 years, p=0.031). This may be due to an association of causes (reduced intestinal motility, intestinal surgery, increased use of medications) in the elderly population [5].
Also previous abdominal surgery and, in particular, the number of prior intestinal surgery seem to be an important risk factor for SIBO development. Several authors reported higher frequency of SIBO in patients with a history of abdominal surgery, especially in patients with ileocecal valve (ICV) involvement [1,4]. In our study, the extent of bowel resection appeared to be related to SIBO development, despite a statistically significance did not emerge. On the contrary, higher number of surgical procedures appeared to be significantly and independently associated to SIBO development (OR=2.8315, 95% CI 1.10525-6.9569, p=0.023).
Although ICV is considered an important factor controlling compartmentalization of colonic bacteria, structural and functional changes, including reduction of the overall small-bowel length and a less effective ileal peristalsis, following intestinal resection procedures, seem to be the major risk factors for SIBO development in patients with CD. Subsequently, the epithelial changes in the setting of SIBO, result in a reduction intestinal micronutrient absorption [13]. In effect, we found median lower level of B12 in patients with SIBO compared to patients without SIBO (p=0.045). Moreover, patients with SIBO reported symptoms such as abdominal pain, bloating and diarrhea though in the present study no differences between patients with and without SIBO was found. This could be explained by the fact that patients with CD could experience overlapping symptoms with SIBO and, consequently, may be impossible to distinguish the underlying disease from SIBO on the basis only of reported symptoms.
As international guidelines and clear recommendations are not available, antibiotic and probiotic treatment, at the dosage and duration used in our study, were chosen on the basis of the patient’s safety profile and on the experience of clinical practice. The treatment was effective and well tolerated, with no side effects reported and normalization of GBT was obtained in 13 out 15 of treated patients. However, no statistical significant
improvement of symptoms was obtained in patients that achieved a normalization in GBT result after treatment. Probably, this feature is due to the small cohort of patients with SIBO. Although, vitamin B12 levels after antibiotic and probiotic treatment increased significantly (p=0.011), suggesting a potential improvement of nutrients absorption following the resolution of bacterial uptake competition, this point needs to be further clarified due to the heterogeneity, regarding vitamin B12 treatment, of our cohort.
The low number of patients treated was not sufficient to perform any statistical analysis in order to establish which antibiotic is the best choice in the management of SIBO in CD patients.
In conclusion, we propose a diagnostic algorithm (Figure 1) that illustrates a
possible approach for the management of CD patients reporting abdominal complaints. If a CD patient, recently undergone to surgery, refers accentuated intestinal symptoms with no evidence of inflammation (normal levels of WBC, CRP and FC) but reduced pattern of absorption (reduced levels of hemoglobin, iron, folic acid or vitamin B12) it is
recommended to consider SIBO as differential diagnosis to CD acute flare and to propose the use of GBT.
Authorship
AG and GPC performed research, analyzed data and wrote the manuscript. PB, DGR, SR and CS performed research and collected data. AS and RP revised the paper critically for important intellectual contents. AR, MA and FB designed the study and managed the study. All authors contributed to the revision of the manuscript. FB is the guarantor of the
integrity of the study.
Declaration of interest: All authors have no conflict of interest and this work was not supported by grants.
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Table I Patients demographic characteristics and surgery.
Overall SIBO No SIBO pa pb
Patients n (%) 68 18 (26.5%) 50 (73.5%)
Age (years) mean ± SD 49.3 ± 12.8 54.3 ± 13.0 47.5 ± 12.3 0.049
Gender M/F 42/26 9/9 33/17 0.267
Disease duration mean ± SD 17.1 ± 10.4 21.2 ± 10.3 15.7 ± 10.2 0.031
Surgical procedures n (%) 58 (85%) 17 (94.5%) 41 (80%) 0.270
Type of surgical procedures
Ileum resection n (%) 2 (4%) 1 (6%) 1 (2%) 0.504
0.373
Ileocecal resection n (%) 18 (32%) 2 (12%) 16 (49%) 0.061
Ileocolon resection n (%) 36 (62%) 14 (82%) 22 (54%) 0.073
Colectomy n (%) 2 (3%) 0 2 (5%) 1.000
Number of surgical procedures
0 n (%) 10 (15%) 1 (5.5%) 9 (18%) 0.270 0.001 1 n (%) 39 (57%) 8 (44.5%) 31 (62%) 0.268 2 n (%) 15 (22%) 5 (28%) 10 (20%) 0.519 3 n (%) 3 (4%) 3 (16.5%) 0 0.016 4 n (%) 2 (1%) 1 (5.5%) 0 0.265
a p-value was calculated by Fisher exact test or Kruskall-Wallis test where appropriated. b p-value was calculated by chi-square test for trend.
Table II Patients clinical and biochemical characteristics.
Overall SIBO No SIBO pa pb
Stool frequency
<3 n (%) 34 (50%) 7 (39%) 27 (54%) 0.410
0.362
3-6 n (%) 21 (31%) 7 (39%) 14 (28%) 0.392
>6 n (%) 13 (19%) 4 (22%) 9 (18%) 0.733
Bristol stool type
1-3 n (%) 14 (21%) 0 14 (28%) 0.014
0.057
4 n (%) 31 (45%) 10 (55%) 21 (42%) 0.411
5-6 n (%) 17 (25%) 6 (33%) 11 (22%) 0.357
7 n (%) 6 (9%) 2 (11%) 4 (8%) 0.652
Symptoms (multiple responses possible)
Abdominal pain n (%) 34 (50%) 12 (66%) 22 (44%) 0.173 Bloating n (%) 31 (45%) 10 (56%) 21 (41%) 0.411 Urgency n (%) 25 (37%) 10 (56%) 15 (30%) 0.086 Weight loss n (%) 9 (13%) 1 (6%) 8 (16%) 0.425 Fever n (%) 4 (6%) 3 (17%) 1 (2%) 0.054 Biochemistry
Hemoglobin (%) median (range) 13.8 (9.9-23.3) 13.6 (9.9-16.6) 13.9 (11.0-23.3) 0.775 Iron (µg/dL) median (range) 77 (15-142) 72 (15-132) 79 (25-142) 0.802 Folate (ng/mL) median (range) 5.4 (1.7-20.0) 4.6 (3.0-9.8) 5.5 (1.7-2.0) 0.411 B12 (pg/mL) median (range) 283 (84-1146) 226 (84-957) 306 (142-1146) 0.045 WBC (10^9/L) median (range) 6.6 (3.4-12.9) 5.9 (4.2-10.2) 6.9 (3.4-12.9) 0.062 CRP (mg/L) median (range) 0.5 (<0.5-17.5) 0.5 (<0.5-17.5) 0.5 (<0.5-16.7) 0.749 FC (µg/g) median (range) 121 (10-343) 98 (10-255) 133 (24-343) 0.179
a p-value was calculated by Fisher exact test or Kruskall-Wallis test where appropriated. b p-value was calculated by chi-square test for trend.
Abbreviations: SIBO= small intestinal bacterial overgrowth; WBC= white blood cells; CRP= C-reactive protein; FC= fecal calprotectin.
Table III Univariate and multivariate logistic regression analysis of factors associated with
the diagnosis of SIBO.
Univariate Multivariate OR 95% CI p OR 95% CI p Age 1.0460 0.9983-1.0959 0.059 1.0341 0.9816-1.0895 0.207 Gender 1.9412 0.6503-5.7947 0.235 1.7248 0.4945-6.0158 0.392 Disease duration 1.0520 0.9980-1.1090 0.059 Pattern of inflammation 1.1882 0.6923-2.0391 0.532 Surgical procedures 3.7317 0.4382-31.7806 0.228 Type of surgical procedures 1.5644 0.5795-4.2232 0.377
Ileocolon resection 4.0303 1.0040-16.1790 0.049 2.6454 0.7429-9.4205 0.133 Number of surgical procedures 3.2934 1.4515-7.4725 0.004 2.8315 1.1525-6.9569 0.023
Stool frequency 1.3729 0.6918-2.7247 0.365
Bristol stool type 1.8296 0.9654-3.4676 0.064
Symptoms Abdominal pain 2.3478 0.7608-7.2449 0.138 Bloating 1.7262 0.5826-5.1145 0.325 Urgency 2.9167 0.9620-8.8427 0.059 Weight loss 0.2941 0.0341-2.5375 0.266 Fever 9.8000 0.9478-101.2244 0.056
Abbreviations: OR= odd ratio; CI= confidence interval.
Table IV Symptoms and biochemical parameters of the 13 patients that reported GBT
normalization after antibiotic and probiotic therapy.
Before therapy After therapy p Symptoms (multiple response possible)
Abdominal pain n (%) 7 (54%) 6 (46%) 1.000 Bloating n (%) 5 (38%) 3 (23%) 0.625 Urgency n (%) 7 (54%) 7 (54%) 1.000 Fever n (%) 3 (23%) 1 (8%) 0.500 Biochemistry Hemoglobin (%) mean ± SD 13.5 ± 1.9 13.6 ±1.7 0.811 Iron (µg/dL) mean ± SD 81 ± 35 80 ± 38 0.593 Folate (ng/mL) mean ± SD 5.2 ± 2.5 4.9 ± 2.2 0.112 B12 (pg/mL) mean ± SD 249 ± 147 331 ± 160 0.011
WBC (10^9/L) mean ± SD 6.1 ± 2.0 6.7 ± 2.4 0.113
CRP (mg/L) mean ± SD 0.5 ± 0.1 0.6 ± 0.3 0.516
Figure 1 Proposed diagnostic algorithm for differential diagnosis of SIBO from Crohn’s
disease acute flare.
a Meteorism, abdominal pain, increased stool frequency.
b Normal pattern of inflammation and reduced pattern of absorption.
Abbreviations: CD= Crohn’s disease; GBT= glucose breath test; US= ultrasound; IBS= irritable bowel syndrome; IBD= inflammatory bowel disease.
