OBJECTIVES: To assess the impact of comorbid depression on healthcare utilization and costs among individuals with IBS enrolled in Fee-for-Service Medicaid program.

METHODS: A retrospective cohort study was conducted using 2006-2008 Medicaid Analytic Extract files for 39 states. Inclusion criteria were any medical claim for IBS in 2007 (first claim being the index date), continuous enrollment in Medicaid, and age 18-64. Beneficiaries were excluded if they were enrolled in long-term care, dual eligible for Medicaid/Medicare, or had claims for confounding diseases. Beneficiaries with one or more medical claims for depression during the study period were considered to have had comorbid depression. Outcomes assessed included 12-month post index date total all-cause and IBS-related healthcare utilization and costs, and for each of the four medical service components – inpatient, outpatient, emergency room, and prescription drug. Generalized linear models were used to assess the impact of comorbid depression on outcomes.

RESULTS: A total of 1,983 beneficiaries were included in the study – 1,450 in the IBS only group and 533 in the IBS and depression group. Beneficiaries with IBS and depression had significantly greater all-cause (220.21 vs 205.52, p<0.001) and IBS-related healthcare utilization (18.86 vs 14.29, p<0.001), and IBS-specific healthcare expenditures ($2,085 vs $1,556, p<0.001) as compared to their non-depressed counterparts. All-cause and IBS-related inpatient, IBS-related outpatient, all-cause emergency room, all-cause and IBS-related prescription drug utilization, and IBS-related outpatient, all-cause and IBS-related emergency room, and all-cause and IBS-related prescription drug costs were the drivers of greater healthcare utilization and costs among the depressed cohort.

CONCLUSIONS: Given the markedly greater healthcare utilization and cost associated with comorbid depression, there seems to be a need for better depression screening and management among adults with IBS. Future studies should examine this relationship in other populations to assess if it is generalizable beyond the Medicaid population.