Estimating the inpatient and outpatient costs of atrial fibrillation and associated adverse events

Thesis (Master's)--University of Washington, 2013<bold>ABSTRACT</bold> <bold>Background</bold> In the last several years three new anticoagulant options have come on to the market, altering the risk/benefit profile of stroke prevention therapy. The development of useful decision analytic models in atrial fibrillation (AF) is contingent on accurate estimates of costs. Estimated costs of AF include not only the cost of treating underlying AF, but also of treating adverse events including ischemic stroke, myocardial infarction (MI), systemic embolism (Se), GI bleed, and intracranial hemorrhage (ICH). <bold>Objective</bold> The aim of this study was to describe the incremental 30, 90, 365 day costs of a stroke, MI, SE, ICH, or GI bleed in patients with AF. <bold>Methods</bold> To determine the incremental cost of each event of interest a matched (1:4) retrospective cohort study was conducted. Data were derived from the Truvan Health MarketScan® 2007 to 2011 Commercial Claims and Medicare Supplemental and Coordination of Benefits Databases. The study cohort consisted of adults with the first diagnosis of AF between January 1, 2007 and December 31, 2010. All patients with incident AF were followed for first inpatient admission with a primary diagnosis of an event of interest. Controls were subjects with AF but without an admission for an event of interest.For bivariate analyses, total average costs for cases and matched controls were compared using a 2-sided, 2-sample t-test assuming unequal variance; and compared to use of a simple ordinary least squares regression with robust standard errors. Multivariate analyses were conducted using generalized linear modeling and generalized estimating equations. <bold>Results</bold> After applying inclusion and exclusion criteria to the 31,961,861 unique persons with an AF diagnosis, 1,788 patients who experienced one event of interest were identified along with 113,581 potential controls. For all events of interest, overall healthcare costs at 30 days, 90 days and 365 days were significantly higher in cases than controls. The mean incremental cost of an ischemic stroke over baseline healthcare costs, 30 days after the event, was $20,710, an MI was $32,535, a SE $15,754, an ICH $45,242, and a GI bleed was $14,823 (2012 US$). At all time points, ICH was the most costly event and maintained the largest difference from controls and from 30 day costs. <bold>Discussion</bold> The results of this study provide unique quantifications of the incremental 30, 90, and 365 day costs of ischemic stroke, MI, ICH, SE, and GI bleed in patients with AF. This analysis is the first to describe the incremental costs of all events of interest in AF, using a single dataset, as well as include out-of-pocket costs in the incremental estimations