One-time screening for abdominal aortic aneurysm in Ontario, Canada: a model-based cost-utility analysis

Abstract

Background: Screening programs for abdominal aortic aneurysm (AAA) are not available in Canada. We sought to determine the effectiveness and costutility of AAA screening in Ontario. Methods: We compared onetime ultrasonographybased AAA screening for people aged 65 years to no screening using a fully probabilistic Markov model with a lifetime horizon. We estimated lifeyears, qualityadjusted lifeyears (QALYs), AAArelated deaths, number needed to screen to prevent 1 AAArelated death and costs (in Canadian dollars) from the perspective of the Ontario Ministry of Health. We retrieved model inputs from literature, Statistics Canada, and the Ontario Case Costing Initiative. Results: Screening reduced AAArelated deaths by 84.9% among males and 81.0% among females. Compared with no screening, screening resulted in 0.04 (18.96 v. 18.92) additional lifeyears and 0.04 (14.95 v. 14.91) additional QALYs at an incremental cost of $80 per person among males. Among females, screening resulted in 0.02 (21.25 v. 21.23) additional lifeyears and 0.01 (16.20 v. 16.19) additional QALYs at an incremental cost of $11 per person. At a willingnesstopay of $50 000 per year, screening was costeffective in 84% (males) and 90% (females) of model iterations. Screening was increasingly costeffective with higher AAA prevalence. Interpretation: Screening for AAA among people aged 65 years in Ontario was associated with fewer AAArelated deaths and favourable costeffectiveness. To maximize QALY gains per dollar spent and AAArelated deaths prevented, AAA screening programs should be designed to ensure that populations with high prevalence of AAA participate.