Should Women be Screened for Abdominal Aortic Aneurysm?

Introduction: The USPSTF currently recommends a one-time ultrasound screening for abdominal aortic aneurysm (AAA) for all men who have ever smoked (B recommendation) and selective screening for men who have never smoked (C recommendation). For women who have ever smoked, the panel decided there is insufficient evidence to make a recommendation (I recommendation) while recommending against screening for women who have never smoked (D recommendation). Our goal was to assess whether women should be screened for AAA by estimating the cost-effectiveness of screening both men and women for AAA.

Methods: We constructed and validated a Markov model of AAA screening at age 65 years using the best available clinical data. The model is an improvement upon previous models by expanding the AAA-related states to allow for different surgery thresholds, explicitly including women and smoking status, differentiating between types of surgery, and modeling reintervention events following surgery. AAA-specific costs (2015 US dollars) were assessed from the healthcare system perspective, benefits were QALYs gained, and both costs and benefits were discounted at 3%. We estimated the number needed to screen (NNS) to identify an AAA and prevent a death related to an AAA rupture. Finally, to assess the joint uncertainty around model parameters, we conducted a probabilistic sensitivity analysis (PSA). The model was analyzed separately for men and women, utilizing 100,000 Monte Carlo simulations with 100 samples for the PSA.

 Results: For men, the NNS to prevent an AAA-related death was 418 when screening smokers and 565 when screening everyone. For women, the NNS were substantially higher at 795 screening smokers and 1540 for screening everyone, due to the lower prevalence of AAA. While the benefits are small at the aggregate level, at the individual level, each avoided rupture led to an average of about 3 discounted QALYs gained and 5 years of increased life expectancy. The ICER for screening male smokers was $11,600 per QALY gained while screening all men was $56,100 per QALY gained. For women, the ICERs were smaller for screening smokers was $9540 per QALY gained and for all women was $42,700 per QALY gained.

 Conclusions: To date, few women have been included in randomized clinical trials, and a trial adequately powered to evaluate the net benefits of screening for AAA in women seems unlikely. However, the primary result of this analysis suggest that screening women may be at least as cost-effective as screening men, which differs from most guideline recommendations. The results of this modeling study could be used to inform future guideline recommendations for AAA screening.