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 ≥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 CHADS₂ (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 CHADS₂ 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 CHADS₂ 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 ∼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.

Key words: :

• Atrial fibrillation
• Burden of illness
• Cerebrovascular events
• Warfarin

Transparency

Declaration of funding

This study was supported by research funding provided by AstraZeneca Pharmaceuticals LP, Wilmington, DE, USA.

Declaration of financial/other relationships

J.K. and O.H. have disclosed that they are employees of AstraZeneca and own AstraZeneca stock options.

All peer reviewers received honoraria for peer reviewing for CMRO; they disclosed no significant relationships with this study or the study sponsor nor any significant competing financial interests or relationships with other commercial entities relevant to the reviewed manuscript's content.

Acknowledgment

The authors acknowledge no outside assistance in preparing this manuscript.