Retrospective Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Apr 21, 2015; 21(15): 4574-4582
Published online Apr 21, 2015. doi: 10.3748/wjg.v21.i15.4574
Predisposing factors for positive D-Xylose breath test for evaluation of small intestinal bacterial overgrowth: A retrospective study of 932 patients
Richard A Schatz, Qing Zhang, Nilesh Lodhia, Jonathan Shuster, Phillip P Toskes, Baharak Moshiree
Richard A Schatz, Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, United States
Qing Zhang, Phillip P Toskes, Department of Gastroenterology, University of Florida, Gainesville, FL 32610, United States
Nilesh Lodhia, Department of Gastroenterology, Medical University of South Carolina, Charleston, SC 29425, United States
Jonathan Shuster, Department of Health Outcomes and Policy, University of Florida, Gainesville, FL 32610, United States
Baharak Moshiree, Department of Gastroenterology, University of Miami, Miami, FL 33136, United States
Author contributions: Schatz RA contributed to the data collection and analysis, drafting, and editing of manuscript; Zhang Q contributed to data collection and analysis; Lodhia N contributed to reviewing and editing the manuscript; Shuster J contributed to the statistical design and analysis; Toskes PP contributed to the design of the project, reviewed and edited the manuscript; and Moshiree B conceived and designed the project and edited the manuscript.
Supported by KL2 Scholar Award to Baharak Moshiree KL2 RR029888-01 from the National Institute of Health (NIH); and NIH grant No. 1UL1TR000064, from the National Center for Advancing Translational Sciences.
Ethics approval: The authors ensure that this retrospective study and manuscript preparation were completed with rigid compliance to the best practices in publication ethics. These standards were upheld according to University of Florida Institutional Review Board and Ethics Committee regulations. Patient data were collected and stored in a de-identified database to which only the investigators had access.
Informed consent: This study was a retrospective chart review using a de-identified patient database. This study was approved for a Waiver of Informed Consent as attached in the Institutional Review Board approval documentation.
Conflict-of-interest: The authors disclose there are no conflicts of interest.
Data sharing: Because these data may be the subject of future research by our team, we will not be able to share these data at this time. However, readers and reviewers can request a copy of a de-identified data set and documented copies of the analytic programs from Dr. Baharak Moshiree at bmoshiree@med.miami.edu. Requests will be honored within 18 mo of the e-publication date of this article, after a signed data user agreement is obtained.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Baharak Moshiree, MD, Associate Professor of Medicine, Department of Gastroenterology, University of Miami, 1475 NW 12th Ave, 1st floor, Miami, FL 33136, United States. bmoshiree@med.miami.edu
Telephone: +1-305-2438644 Fax: +1-305-2433762
Received: September 6, 2014
Peer-review started: September 7, 2014
First decision: October 29, 2014
Revised: November 15, 2014
Accepted: January 8, 2015
Article in press: January 8, 2015
Published online: April 21, 2015
Processing time: 226 Days and 6.3 Hours
Abstract

AIM: To investigate, in the largest cohort to date, patient characteristics and associated risk factors for developing small intestinal bacterial overgrowth (SIBO) using the D-Xylose breath test (XBT).

METHODS: We performed a retrospective cross-sectional study to analyze patient characteristics who underwent the XBT for evaluation of SIBO. Diagnostic testing with the XBT was performed based on a clinical suspicion for SIBO in patients with symptoms of bloating, abdominal pain, abdominal distension, weight loss, diarrhea, and/or constipation. Consecutive electronic medical records of 932 patients who completed the XBT at the University of Florida between 2005 and 2009 were reviewed. A two-way Analysis of Variance (ANOVA) was used to test for several associations including age, gender, and body mass index (BMI) with a +XBT. A two-way ANOVA was also performed to control for the differences and interaction with age and between genders. A similar analysis was repeated for BMI. Associations between medical conditions and prior surgical histories were conducted using the Mantel-Haenszel method for 2 by 2 contingency tables, stratified for gender. Reported odds ratio estimates reflect the odds of the prevalence of a condition within the +XBT group to that of the -XBT group. P values of less than 0.05 (two-sided) were considered statistically significant.

RESULTS: In the 932 consecutive eligible subjects studied, 513 had a positive XBT. A positive association was found between female gender and a positive XBT (P = 0.0025), and females with a positive test were, on average, greater than 5 years older than those with a negative test (P = 0.024). The mean BMI of positive XBT subjects was normal (24.5) and significantly lower than the subjects with a negative XBT (29.5) (P = 0.0050). A positive XBT was associated with gastroesophageal reflux disease (GERD) (OR = 1.35; 95%CI: 1.02-1.80, P = 0.04), peptic ulcer disease (PUD) (OR = 2.61; 95%CI: 1.48-4.59, P < 0.01), gastroparesis (GP) (OR = 2.04; 95%CI: 1.21-3.41, P < 0.01) and steroid use (OR = 1.35; 95%CI: 1.02-1.80, P = 0.01). Irritable bowel syndrome, independent proton-pump inhibitor (PPI) usage, or previous abdominal surgery was not significantly associated with a positive XBT. No single subdivision by gender or PPI use was associated with a significant difference in the odds ratios between any of the subsets.

CONCLUSION: Female gender, lower BMI, steroid use, PUD, GERD (independent of PPI use), and GP were more prevalent in patients with SIBO, determined by a positive XBT. Increasing age was associated with SIBO in females, but not in males.

Keywords: Intestine; Small; Irritable bowel syndrome; Xylose; Breath tests; Proton pump inhibitors; Gastroparesis; Bacteria

Core tip: Our study represents the largest retrospective cohort to date of 932 patients evaluated for small intestinal bacterial overgrowth (SIBO) using the D-Xylose breath test (XBT). We found that a positive test for SIBO was seen more frequently in elderly females than males and that lower body mass index, reflux disease, ulcer disease, gastroparesis, and steroid use were more frequently seen in patients who tested positive with the XBT compared to those with a negative test. Our study did not show any association between SIBO and irritable bowel syndrome or independent narcotic or proton-pump inhibitor usage as has previously been reported by some investigators.