AIM: To determine effect of irritable bowel syndrome(IBS) subtype on IBS-specific quality of life(QOL) questionnaire and its subscales.METHODS: We studied IBS patients visiting our functional gastroenterology disorder clinic at a tertiary care center of Unites States.IBS and IBS subtype were diagnosed using Rome-Ⅲ questionnaire.QOL was assessed using IBS-QOL questionnaire.IBSQOL assesses quality of life along eight subscales: dysphoria,interference with activities,body image,health worry,food avoidance,social reactions,sexual health,and effect on relationships.IBS-QOL and its subscales were both scored on a range of 0-100 with higher scores suggestive of better QOL.Results of overall IBS-QOL scores and subscale scores are expressed as means with 95%CI.We compared mean IBS-QOL score and its subscales among various IBSsubtypes.Analysis of variance(ANOVA) was used to compare the mean difference between more than two groups after controlling for age and gender.A posthoc analysis using Bonferroni correction was used only when P value for ANOVA was less than 0.05.RESULTS: Of 542 patients screened,243 had IBS as per Rome-Ⅲ criteria.IBS-mixed(IBS-M) was the most common IBS subtype(121 patients,49.8%) followed by IBS- diarrhea(IBS-D)(56 patients,23.1%),IBSconstipation(IBS-C)(54 patients,22.2%) and IBSunspecified(IBS-U)(12 patients,4.9%).Overall IBSQOL scores were significantly different among various IBS-subtypes(P = 0.01).IBS-QOL of patients with IBS-D(61.6,95%CI: 54.0-69.1) and IBS-M(63.0,95%CI: 58.1-68.0) was significantly lower than patients with IBS-C(74.5,95%CI: 66.9-82.1)(P = 0.03 and 0.02 respectively).IBS-D patients scored significantly lower than IBS-C on food avoidance(45.0,95%CI: 34.8-55.2 vs 61.1,95%CI: 50.8-71.3,P = 0.04) and interference with activity(59.6,95%CI: 51.4-67.7 vs 82.3,95%CI: 74.1-90.6,P < 0.001).IBS-M patients had more interference in their activities(61.6,95%CI: 56.3-66.9 vs 82.3,95%CI: 74.1-90.6,P = 0.001) and greater impact on their relationships(73.3,95%CI: 68.4-78.2 vs 84.7,95%CI: 77.2-92.2,P = 0.02) than IBS-C patients.Patients with IBS-M also scored significantly lower than IBS-C on food avoidance(47.2,95%CI: 40.7-53.7 vs 61.1,95%CI: 50.8-71.3,P = 0.04) and social reaction(66.1,95%CI: 61.1-71.1 vs 80.0,95%CI: 72.1-87.7,P = 0.005).CONCLUSION: IBS-D and IBS-M patients have lower IBS-QOL than IBS-C patients.Clinicians should recognize food avoidance,effects on daily activities and relationship problems in these patients. AIM: To determine effect of irritable bowel syndrome (IBS) subtype on IBS-specific quality of life (QOL) questionnaire and its subscales. METHODS: We studied IBS patients visiting our functional gastroenterology disorder clinic at a tertiary care center of Unites States. and IBS subtype were diagnosed using Rome-Ⅲ questionnaire. QOL was assessed using IBS-QOL questionnaire. IBSQOL assesses quality of life along eight subscales: dysphoria, interference with activities, body image, health worry, food avoidance, social reactions, sexual health, and effect on relationships. IBS-QOL and its subscales were both scored on a range of 0-100 with higher scores suggestive of better QOL. Results of overall IBS-QOL scores and subscale scores are expressed as means with 95% CI.We compared mean IBS-QOL score and its subscales among various IBSsubtypes.Analysis of variance (ANOVA) was used to compare the mean difference between more than two groups after controlling for age and gender. A posthoc analysis using Bo Of the 542 patients screened, 243 had IBS as per Rome-III criteria. IBS-mixed (IBS-M) was the most common IBS subtype (121 patients, 49.8%) followed by IBS-diarrhea (56 patients, 23.1%), IBSconstipation (IBS-C) (54 patients, 22.2%) and IBSunspecified IBSQOL scores were significantly different among various IBS-subtypes (P = 0.01). IBS-QOL of patients with IBS-D (61.6,95% CI: 54.0-69.1) and IBS- M (63.0,95% CI: 58.1-68.0 ) were significantly lower than patients with IBS-C (74.5, 95% CI: 66.9-82.1) (P = 0.03 and 0.02 respectively) : 34.8-55.2 vs 61.1, 95% CI: 50.8-71.3, P = 0.04) and interference with activity (59.6, 95% CI: 51.4-67.7 vs 82.3, 95% CI: 74.1-90.6, P <0.001) -M patients had more interference in their activities (61.6, 95% CI: 56.3-66.9 vs 82.3, 95% CI: 74.1-90.6, P = 0.001) and greater impact on their relatio nshi(73.3, 95% CI: 68.4-78.2 vs 84.7, 95% CI: 77.2-92.2, P = 0.02) than IBS-C patients. Patients with IBS-M also scored significantly lower than IBS- , 95% CI: 40.7-53.7 vs 61.1, 95% CI: 50.8-71.3, P = 0.04) and social reaction (66.1, 95% CI: 61.1-71.1 vs 80.0, 95% CI: 72.1-87.7, P = 0.005 ). CONCLUSION: IBS-D and IBS-M patients have lower IBS-QOL than IBS-C patients. Clinicians should recognize food avoidance, effects on daily activities and relationship problems in these patients.