Impact of small intestinal bacterial overgrowth on symptoms and quality of life in irritable bowel syndrome.

OBJECTIVE: To explore the factors associated with small intestinal bacterial overgrowth (SIBO), and to further evaluate the impact of SIBO on irritable bowel syndrome (IBS) in terms of symptom severity and health-related quality of life (HRQoL). METHODS: A cross-sectional study of consecutive adult patients who underwent glucose hydrogen breath test was conducted. Factors associated with SIBO were evaluated. Symptom severity and HRQoL of IBS patients with and without SIBO were compared. The independent factors associated with severe IBS were explored. RESULTS: 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 (50.0% vs 29.0%, P = 0.019). Severe IBS was associated with SIBO (36.4% vs 15.6%, P = 0.043). SIBO was associated with poorer HRQoL (Euroqol five-dimensional utility score: 0.73 vs 0.80, P = 0.024). 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 in the univariate analysis. However, SIBO was the only independent factor associated with severe IBS in the multivariate analysis (adjusted odds ratio 3.83, 95% confidence interval CI 1.02-14.34, P = 0.046). CONCLUSIONS: There was a significant association between IBS-D and SIBO. The coexistence of SIBO had a significant negative impact on IBS patients.

Small Intestinal Bacterial Overgrowth In Various Functional Gastrointestinal Disorders: A Case-Control Study.

INTRODUCTION: Small intestinal bacterial overgrowth (SIBO) is prevalent in irritable bowel syndrome (IBS), but its' association with other functional gastrointestinal disorders (FGIDs) is less certain. This study aimed to explore SIBO in a multi-racial Asian population with various FGIDs compared to non-FGID controls. METHODOLOGY: Consecutive Asian adults with Rome III diagnosed common FGIDs (functional dyspepsia/FD, IBS and functional constipation/FC) and non-FGID controls were subjected to glucose breath testing, with hydrogen (H2) and methane (CH4) levels determined. RESULTS: A total of 244 participants (FGIDs n = 186, controls n = 58, median age 45 years, males 36%, Malay ethnicity 76%) were recruited. FGIDs had a higher prevalence trend of SIBO compared to controls (16% FGIDs vs. 10% controls, p = 0.278) with 14% in FD, 18% in IBS and 17% in FC. Compared to controls, SIBO was associated with diarrhoea-predominant IBS (IBS-D) (24% vs. 10%, P = 0.050) but not with other types of FGIDs. IBS-D remained an independent predictor of SIBO (OR = 2.864, 95% CI 1.160-7.071, p = 0.023) but not PPI usage nor history of diabetes (both p > 0.050) at multivariate analysis. Compared to controls, SIBO in IBS-D was associated with an elevated H2 level (≥ 20 ppm from baseline) (18% vs. 3%, p = 0.017), but not CH4 levels (≥ 10 ppm) (9% vs. 7%, p = 0.493). In addition, no difference was found in the prevalence of methane-positive SIBO between chronic constipation (constipation-predominant IBS and FC) compared to controls (9% vs. 7%, P = 0.466). CONCLUSION: SIBO is prevalent amongst multi-ethnic Asian adults with and without FGIDs. Amongst various FGIDs, only IBS-D is significantly associated with SIBO.

The epidemiology and quality of life of functional gastrointestinal disorders according to Rome III vs Rome IV criteria: A cross-sectional study in primary care.

OBJECTIVE: To explore the differences in frequency and epidemiology of functional gastrointestinal disorders (FGIDs) in a primary care setting, and to examine the health-related quality of life (HRQOL) and healthcare utilization of FGID patients based on the Rome III and Rome IV criteria. METHODS: A cross-sectional study of consecutive adults in a primary healthcare setting was conducted. Differences in epidemiology, and HRQOL of common FGIDs (functional dyspepsia [FD], irritable bowel syndrome [IBS], functional diarrhea, functional constipation [FC]) between the Rome III and IV criteria were explored. RESULTS: Among a total of 1002 subjects recruited, the frequency of common FGIDs was 20.7% and 20.9% among subjects based on the Rome III and Rome IV criteria, respectively. The frequency of IBS reduced from 4.0% (Rome III) to 0.8% (Rome IV), while that of functional diarrhea increased from 1.2% (Rome III) to 3.3% (Rome IV). In contrast, there was no significant change in the frequency of FD (7.5% [Rome III] vs 7.6% [Rome IV]) and FC (10.5% [Rome III] vs 11.7% [Rome IV]). Most of the Rome III IBS subjects (52.5%, n = 21) who did not meet Rome IV IBS criteria, fulfilled the criteria for FC, functional diarrhea, FD, or overlap syndrome. Subjects with all FGIDs, regardless of criteria, had more healthcare utilization and lower HRQOL compared to non-FGID controls. CONCLUSIONS: The Rome IV criteria alter the frequency of IBS and functional diarrhea, but not FD and FC, when compared to the Rome III criteria. Regardless of criteria, FGIDs had a significant impact on healthcare burden and HRQOL.

The association of body mass index with functional dyspepsia is independent of psychological morbidity: A cross-sectional study.

BACKGROUND AND AIM: The association between body mass index (BMI) and functional gastrointestinal disorders (FGIDs) has been inconsistent. We aimed to explore the association of BMI with FGIDs in a primary care setting to provide more data in this area. METHODS: A cross-sectional study of consecutive Asian adults attending a primary healthcare setting was conducted. This study was conducted in 2 phases: The association between BMI and common FGIDs (functional diarrhea/FD, irritable bowel syndrome/IBS, functional diarrhea and functional constipation/FC) was studied initially. The influence of anxiety and depression on BMI and FGIDs was additionally explored in phase 2. RESULTS: A total of 1002 subjects (median age 32 years, 65.4% females, 90.7% Malay ethnicity, 73.2% higher than secondary level education) were recruited between August 2019 to January 2020. The majority of subjects were obese (39.2%), and had central obesity (51.7%), while 6.1% had metabolic syndrome. The prevalence of FD, IBS, functional diarrhea and FC were 7.5% (n = 75), 4.0% (n = 40), 1.2% (n = 12) and 10.5% (n = 105) respectively, based on the Rome III criteria. Among individual FGIDs, FD subjects had more underweight adults (BMI<18.5kg/m2) compared to controls (13.3% vs 3.5%, P = 0.002) and being underweight remained as an independent association with FD [OR = 3.648 (95%CI 1.494-8.905), P = 0.004] at multi-variate analysis. There were no independent associations between BMI and other FGIDs. When psychological morbidity was additionally explored, anxiety (OR 2.032; 95%CI = 1.034-3.991, p = 0.040), but not depression, and a BMI<18.5kg/m2 (OR 3.231; 95%CI = 1.066-9.796, p = 0.038) were found to be independently associated with FD. CONCLUSIONS: FD, but not other FGIDs, is associated with being underweight. This association is independent of the presence of anxiety.