Use of broad-spectrum antibiotics and the development of irritable bowel syndrome.

BACKGROUND Irritable bowel syndrome (IBS) is a functional bowel disorder with an estimated prevalence of 9% to 22% in the United States. It is responsible for 28% of gastroenterology visits, with associated health care costs of $8 billion annually. Yet, IBS etiology is the subject of much debate. OBJECTIVES Our study examines a possible relationship between IBS and exposure to broad-spectrum antibiotics. It is known that antibiotics alter the colonic flora; we hypothesize that this can create the manifestations seen in IBS patients. METHODS Following approval by the Gundersen Clinic, Ltd Human Subjects Committee/IRB, the medical records of adults who were started on a broad-spectrum antibiotic at Gundersen Lutheran Health System between January 1, 2008, and December 31, 2008, were reviewed retrospectively. From this population, we identified those who developed IBS within 12 months and compared their demographic and clinical characteristics with the characteristics of those who did not. RESULTS Of the 26,107 adult patients exposed to broad-spectrum antibiotics during the study period, 115 received an IBS diagnosis within 12 months. Most were women (84%; n = 97), and they had a higher prevalence of associated comorbidities than those who did not develop IBS. Patients indicated for macrolide or tetracycline use had a higher proportion of IBS development within 12 months; indication for tetracycline use maintained significance even after controlling for sex and comorbid conditions (odds ratio; 1.48; P = .046). CONCLUSION Use of broad-spectrum antibiotics--particularly macrolides or tetracyclines--may be associated with IBS development. To date, we know of no other study that has associated these antibiotics with IBS development. Further studies are necessary.