Natural History and Outcomes of Individuals With Functional Bowel Disorder: A 9-year Population-Based Longitudinal Study

INTRODUCTION: Long-term studies characterizing the natural history of functional bowel disorder (FBD) from community-based settings and exploring association with psychological factors are sparse. We aimed to evaluate the evolution of symptoms, health outcomes, and association of FBD with psychological disorders in Chinese population. METHODS: Individuals identified from random sampling of residents of Hangzhou, China, participated in a baseline survey in January 2010. Follow-up phone survey was conducted in December 2018. FBD was diagnosed based on Rome III criteria. RESULTS: Among 452 individuals (mean age 44.6 +/- 15.3 years, 174 [38%] male) who completed the study, the prevalence of FBD was 36.3% (95% confidence interval [CI] 32.6-40.0%) at enrollment and 36.1% (95% CI 32.3-39.8%) at follow-up survey (P = 0.94). However, 214 individuals (47%) had interval change in diagnosis. Although no difference in incidence of organic disease or death was observed, a higher proportion of patients with FBD (16/164, 9.8% vs 9/288, 3.1%; P = 0.003) compared with those without FBD received non-cancer-related abdominal and/or pelvic surgery during follow-up. FBD was associated with anxiety and/or depression at initial (adjusted odds ratio [AOR] = 1.7, 95% CI 1.7-2.7, P = 0.02) and follow-up (AOR = 8.0, 95% CI 3.2-20.0, P < 0.001) surveys. Diagnosis of FBD at baseline was associated with new-onset anxiety and/or depression at follow-up (AOR = 3.2, 95% CI 1.2-8.3, P = 0.01). DISCUSSION: Although the prevalence of FBD remained stable, transformation of symptoms was common over time. Patients with FBD may have increased risk of receiving non-cancer-related abdominal and/or pelvic surgery. FBD symptoms at baseline increased the risk of new-onset anxiety and/or depression by 3.2-fold over the next 9 years.