Retrospective study of total healthcare costs associated with chronic nonvalvular atrial fibrillation and the occurrence of a first transient ischemic attack, stroke or major bleed

Abstract

Objective: To determine the direct healthcare costs associated with the onset of chronic nonvalvular atrial fibrillation (CNVAF), warfarin utilization and the occurrence of cerebrovascular events in a commercially-insured population.

Research design and methods: This retrospective, observational cohort study utilized medical and pharmacy claims from a large, geographically diverse managed-care organization (N = 18.5 million) to identify continuously benefit-eligible CNVAF patients > or =45 years of age without prior valvular disease or warfarin use between January 1, 2001 and June 1, 2002. All patients were followed at least 6 months, until plan termination or the end of study follow-up. Stroke risk was assessed using the CHADS(2) (stroke-risk) index; warfarin use was defined as having filled at least one pharmacy claim. Inpatient and outpatient cost benchmarks were utilized to estimate total direct healthcare costs (pre- and post-AF index claim). For patients with transient ischemic attacks (TIA), ischemic stroke (IS) and major bleed (MB) total direct healthcare costs were also assessed. The limitations of this study included a descriptive retrospective study design without a comparison group or adjustment for baseline disease severity and drug exposure, as well as, the reliance upon administrative claims data and use of a standardized reference costing methodology.

Results: The pre- and post-AF onset total direct healthcare costs (pmpm) for 3891 incidence CNVAF patients were $412 and $1235, respectively, a 200% increase. Of the 448 (12%) patients with a cerebrovascular event, pmpm costs post-AF ranged from $2235 to $3135 correlating with CHADS(2) stroke-risk status and exposure to warfarin. Total cohort pmpm costs pre and post event increased 24% from $3446.91 to $4262.12. Approximately 20% of all events occurred <2 days and 46% within 1 month after the index AF claim. Any warfarin exposure, regardless of CHADS(2) risk had an 18% to 29 % decrease in pmpm costs.

Conclusions: Post-AF total direct healthcare costs were 3 times greater than pre-AF costs. For those with a TIA, IS or MB, post-AF total direct healthcare costs increased 4.5 times from pre-AF costs; overall post-event costs in this cohort increased approximately 25% over pre-event costs. Nearly half of the events occurred within 1 month of a claim associated with an AF diagnosis. Warfarin exposure appeared to be associated with lower pmpm costs in this population.