Common Clinical Conditions Associated with Small Intestinal Bacteria Overgrowth: A Retrospective Study of 401 Patients

Abstract

Purpose: Small intestinal bacteria overgrowth (SIBO) is commonly associated with variety of clinical conditions; however, its true etiology is unknown. In this study, we reviewed 401 SIBO patients to determine the prevalence of SIBO as a first step for determining which risk factors are causative and which are merely correlative with SIBO in order to guide future focused therapy for more common etiologies. Methods: We retrospectively reviewed the medical records of 401 SIBO patients diagnosed by a positive 14C D-xylose breath test from 2005 to 2009. All of the GI clinical visit notes including symptoms, medication use, past medical history, past surgical history, and abdominal image studies were reviewed. Results: Of 401 SIBO patients, M:F 35:366 (ratio 1:9.6), median age 60 years (age range 21-88), 262 (65.3%) patients had history of abdominal surgeries, 93 (23.2%) had one surgical procedures, 91 (22.7%) had two procedures, 49 (12.2%) had three procedures, and 29 (7.2%) had more than three procedures. Most commonly performed surgeries were hysterectomy, cholecystectomy, and appendectomy (See table below). Commonly associated medical conditions were hypertension, GERD, hypothyroidism, IBS, and diabetes. Long term medication use was as follows: PPI use in 140 (34.9%), narcotic use in 58 (14.5%), and anticholinergics medication use in 44 (11%). Conditions previously commonly associated with SIBO, including scleroderma, celiac disease, IBD, and cirrhosis accounted for a surprisingly small proportion of SIBO in this cohort. Conclusion: SIBO was found mostly in elderly female patients. Most of the patients had multiple prior abdominal surgeries with prior hysterectomy, cholecystectomy, and appendectomy as the most common procedures associated with SIBO. Chronic PPI and narcotic use was frequently seen in SIBO. The most common medical conditions were hypertension, GERD, IBS, and endocrinologic diseases such as hypothyroidism and diabetes. Contrary to current clinical understanding, celiac disease and IBD were not common etiologies for SIBO. (NIH grant 1UL1RR029890).Table: Table. Common clinical conditions associated with SIBO