Impact of Small Intestinal Bacterial Overgrowth on Symptoms and Quality of Life in Irritable Bowel Syndrome.

Abstract

Small intestinal bacterial overgrowth (SIBO) is recognised to have an association with irritable bowel syndrome (IBS), but the impact of SIBO on symptoms and health-related quality of life (HRQOL) in IBS patients is still unknown. A cross-sectional study of consecutive adult patients who underwent glucose hydrogen breath test was conducted. Factors associated with SIBO were evaluated. Symptom and HRQOL of IBS patients with and without SIBO were compared. The independent factors associated with severe IBS (i.e. IBS symptom severity score: IBS-SSS > 300) were explored. A total of 160 patients were included (median age 40 years, males 31.3%). IBS was present among 53.8% of subjects, with 33.8% having diarrhea-predominant IBS (IBS-D). SIBO was diagnosed in 22.5% of the study population. Patients with SIBO were more commonly diagnosed with IBS-D than those without SIBO (SIBO: 50.0% vs non-SIBO: 29.0%, p = 0.019). Amongst IBS patients, severe IBS was associated with SIBO (36.4% vs 15.6%, p = 0.043). The presence of SIBO was associated with poorer HRQOL (EQ-5D utility score: 0.73 (0.69-0.78) vs 0.80 (0.73-1.00), p = 0.024]. The presence of SIBO (44.4% vs 20.6%, p = 0.043), anxiety (77.8% vs 39.7%, p = 0.004) and depression (50.0% vs 19.1%, p = 0.011) were associated with severe IBS at univariate analysis. However, SIBO was the only independent factor associated with severe IBS at multivariate analysis [OR: 3.83 (95% CI: 1.02-14.34), p = 0.046]. There was a significant association between IBS-D and SIBO. The co-existence of SIBO had a significant negative impact on IBS patients. This article is protected by copyright. All rights reserved.