Impact of functional gastrointestinal disorders on survival in the community.

OBJECTIVES: Functional gastrointestinal disorders (FGIDs) comprise a constellation of symptoms that have no identifiable structural or biochemical abnormality. In view of the lack of data from large-scale population-based studies evaluating the effects of these disorders on survival, we aimed to examine whether FGIDs are associated with impaired survival.
METHODS: Between 1988 and 1993, valid self-report questionnaires that recorded gastrointestinal symptoms required for the diagnosis of irritable bowel syndrome (IBS), chronic constipation, chronic diarrhea, dyspepsia, and abdominal pain were mailed to randomly selected cohorts of Olmsted County, Minnesota residents. Minnesota administrative death records were used to identify which of the survey respondents had died over the follow-up period (through April 2008). The association between survival and each FGID was assessed using proportional hazards regression models with univariate and adjusted hazard ratios (HRs, 95% confidence intervals (CIs)), adjusting for age at time of survey, gender, smoking, alcohol, marital status, and Charlson Comorbidity Index (CCI).
RESULTS: Of the 5,262 randomly selected eligible subjects who received a questionnaire, a total of 4,176 responded to the surveys (overall response rate 79%). From these respondents, 243 subjects were excluded because of lack of research authorization (or were registered solely at a different medical institution in Olmsted County, MN), resulting in 3,933 eligible subjects for analysis (eligible response rate 75%); 10% reported symptoms of IBS; 16% chronic constipation; 18% chronic diarrhea; 2% dyspepsia; and 15% abdominal pain. At baseline, the mean (s.d.) age was 54 (18) years, and 52% were female. No association with overall survival was detected for IBS (HR=1.06 (95% CI: 0.86-1.32)), chronic diarrhea (HR=1.03 (95% CI: 0.90-1.19)), abdominal pain (HR=1.09 (95% CI: 0.92-1.30)), or dyspepsia (HR=1.08 (95% CI: 0.58-2.02)). Reporting symptoms of chronic constipation was associated with poorer survival (HR=1.23 (95% CI: 1.07-1.42)). This association remained significant after adjusting for the CCI (HR=1.19 (95% CI: 1.03-1.37)).
CONCLUSIONS: In this large population-based cohort study with over 30,000 person-years of follow-up, no significant association was observed between survival and IBS, chronic diarrhea, dyspepsia, or abdominal pain. Furthermore, no association was found between increasing burden of FGIDs and survival. However, in contrast to these other FGIDs, subjects with symptoms of chronic constipation were found to be at increased risk of poorer survival. Further investigation is required to determine the cause of this observed association.