Su1040 Longitudinal Direct Medical Costs Associated With Irritable Bowel Syndrome-Constipation and Chronic Idiopathic Constipation in a Population-Based Sample Over a 10-Year Period

Abstract

Purpose: : It is estimated that ~ 10-15% of adults have irritable bowel syndrome with approximately 30% of those having irritable bowel syndrome with constipation (IBS-C). Chronic idiopathic constipation (CIC) affects up to 10-15 % of adults in the general population. Constipation has been shown to be the second most common ambulatory digestive disease diagnosis accounting for over 6.5 million visits per year in the United States. Little is known about economic burden of these disorders in terms of numbers of medical visits and diagnostic procedures compared to the general population. The purpose of this study was to compare direct medical costs of population-based cohorts with and without IBS-C and CIC over a 10-year period. Methods: A nested case-control sample was identified through a population-based survey in Olmsted County, MN. The study cohort was comprised of adult respondents to a mailed survey of gastrointestinal symptoms, many specifically related to constipation, and who had given prior research authorization (n= 3831). Cases consisted of 115 adults identified as having IBS-C and 365 identified as having CIC based on survey responses (modified Rome criteria II). Controls were matched 2:1 to cases on gender, age (+ 5 years), and registration date, a proxy for time in the community (+ 5 years). Patient level administrative data on health care utilization and associated costs were accessed for a ten-year period (1999-2008) prior to the survey. Utilization and costs were compared using the Chi-square statistic, Fisher's exact test, and the Wilcoxon Rank Sum statistic. Results: IBS-C cases reported more bloating (p,0.0001) and functional dyspepsia symptoms (p,0.0001), while there were no differences in the CIC cases to controls. There were no differences in Charlson comorbidities in the IBS-C group; there were significantly more multiple sclerosis cases in the CIC cases than controls. Among GI-specific comorbidities, IBS-C cases had a higher prevalence of pancreatitis (p=0.02) than controls. Hospital and ER visits were not greater in IBS-C cases. However, IBS-C cases were found to have higher costs in imaging (p=0.02) (Table 1). Unadjusted resource utilization did not demonstrate differences for CIC compared to controls. CIC cases had higher costs in the area of procedural costs (p=0.04) and trended higher in total costs, and diagnostic tests (Table 2). Conclusions: Over 10 years, costs related to imaging and related to procedures and diagnostic tests were significantly higher for those with IBS-C and CIC, respectively. Although acute care-related utilization and other health care costs were consistently higher in the IBS-C and CIC groups, results were not significantly different in this modest sample. This suggests increased economic burden related to outpatient diagnostic testing for IBS-C and CIC even among community-based individuals. Table 1. Unadjusted All-Cause Resource Utilization and Costs by IBS-C Group