Characterizing Healthcare Utilization, Direct Costs, and Comorbidities Associated with Interstitial Cystitis: A Retrospective Claims Analysis

Thesis (Master's)--University of Washington, 2016-06

Introduction Interstitial Cystitis (IC) is a debilitating condition that affects up to five percent of the United States (US) population.1 The condition is characterized by bladder pain, urinary urgency and frequency, and in some patients, bladder lesions called Hunner’s Lesions (HL). Patients with HL experience a clinical course distinctly different from patients without HL.2 Prior research describing the burden of IC is outdated and lacks HL-level detail. This study aims to characterize healthcare utilization, direct costs, and comorbidities associated with IC, and among IC patients, elucidate differences between those with and without HL. Methods A retrospective analysis was conducted using healthcare claims from the Truven Health MarketScan® Research Databases. Adults with an incident IC diagnosis between 2009 and 2014 were identified and matched to non-IC patients on age, gender, and geographic region. Healthcare utilization, direct costs, and comorbidities during the first 12 months after diagnosis were compared between the two groups, as well as between IC subgroups with and without HL. Results IC patients (n=24,836) were predominantly (92%) female, with a mean age of 49.0 (SD = 15.3) years. IC patients utilized significantly more healthcare resources across all categories compared to non-IC patients. On average, having IC was associated with $6,798 higher total healthcare costs than not having IC (95% CI: $6,253, $7,343), with outpatient costs contributing to 71% of the difference, after adjusting for baseline age, gender, region, insurance type, plan type, and CCI. The odds of developing IC-related comorbidities were 2.61 times greater in IC patients compared to non-IC patients (95% CI: 2.52, 2.70), adjusting for baseline age, sex, region, and CCI. Among IC patients, the HL subgroup (n=292) utilized more healthcare resources, and having HL was associated with $6,486 higher total healthcare costs compared to not having HL (95% CI: $3,497, $9,475) after adjusting for baseline age, gender, region, insurance type, and plan type. Conclusion Our findings suggest that patients with IC have significantly higher healthcare utilization, costs, and comorbidities compared to non-IC patients. This economic burden is further amplified in those with HL.