Economic Burden of Microscopic Colitis in Relation to Disease Activity: A Nationwide Cost-of-illness Study

Background and Aims Microscopic colitis (MC) is a chronic gastrointestinal disease with disabling symptoms and associated comorbidities. Yet, the economic impact of MC has not been studied. In this cost-of-illness study, we estimated the economic burden of MC. Methods We used histopathology reports from Sweden’s all 28 pathology department to identify 11,517 adult patients with biopsy-proven MC as of Jan 1, 2017. Each patient was compared to up to five general-population comparators matched on sex, age, and county of residence. Mean costs for the calendar year of 2016 were calculated based on nationwide register data encompassing healthcare use, dispensed medications, and work loss derived from sick leave and disability leave. Number of budesonide treatments following MC diagnosis was used as a proxy for disease activity. Mean differences were further adjusted for education level. Results Compared with the general population, patients with MC had an annual mean excess cost of $4,805 (USD; adjusted mean difference [95%CI], $4,974 [$4,650; $5,298]), corresponding to a cost ratio of 1.84 (95%CI, 1.74; 1.95). Based on an estimated disease prevalence of ∼0.1%, the economic burden of MC was $1.2 million per 100,000 inhabitants. No significant cost differences were seen based on subtype or sociodemographic factors. However, a high disease activity was associated with higher costs driven by excess work loss. Conclusion Compared with the general population, patients with MC had almost twice as high annual mean costs. Excess costs were particularly high in patients with a high disease activity at onset, mainly driven by work loss.