Abstract 322: Cost Effectiveness Analysis of Peripheral Arterial Disease Screening With the Ankle-Brachial Index Test

Abstract

Introduction: Screening for asymptomatic PAD (aPAD) with the ankle-brachial index (ABI) test may reduce mortality and disease progression by identifying individuals who may benefit from early initiation of cardiovascular (CV) risk reduction therapies. Methods: Using a Markov model, we evaluated the cost-effectiveness of initiating medical therapy (e.g. statin & ACE-inhibitor) after a positive ABI screen in adults 65-years old. We modeled progression to symptomatic PAD (sPAD) and CV mortality with and without screening evaluating quality adjust life years (QALY). Cost of the ABI test, physician visit, new medication, and surgery for sPAD were calculated. Our baseline model estimated 96% of patients already eligible for medical therapy given the similar risk factor profiles of aPAD and CV disease. Repeated screening was considered given the imperfect screening test, development of disease with age, and opportunity to re-initiate therapy given limited medication compliance. Variables with uncertainty underwent a tornado analysis to determine variables with large effects. Results: Our model found an incremental cost of $367 and incremental QALY of 0.0022 with one-time ABI screening resulting in an incremental cost-effectiveness ratio (ICER) of $169,025/QALY over a 35-year period. Removing the benefits of medication on CV mortality increases the ICER by 51%, and removing the benefits of medication on PAD progression increases the ICER by 16%. A tornado diagram shows variables affecting the ICER (Figure). Screening high-risk populations, such as tobacco users where the prevalence of PAD may be 2.5x higher than the general population of 9%, decreases the ICER to $63,500/QALY. Conclusions: Our cost-effective analysis predicts that one-time ABI screening does not meet generally accepted thresholds for cost effectiveness. Disease prevalence and medication adherence had the largest effects on the ICER and are important to consider in implementing ABI screening.