Cost-effectiveness of surgery for small abdominal aortic aneurysms on the basis of data from the United Kingdom small aneurysm trial

Abstract

Purpose: Although the United Kingdom small aneurysm trial reported no survival benefit for early operation in patients with small (4.0–5.5 cm) abdominal aortic aneurysms (AAAs), the trial lacked statistical power to detect small but potentially meaningful gains in life expectancy, particularly for specific subgroups. We used decision analysis to better characterize the potential benefits and cost-effectiveness of early surgery.Methods: We used a Markov model to assess the marginal cost-effectiveness (incremental cost per quality-adjusted life year [QALY] saved) of early surgery relative to surveillance for small AAAs, using data from the UK Trial. Subgroup analyses were performed by patient age and AAA diameter. Sensitivity analysis was used to evaluate the effect of elective operative mortality on cost-effectiveness.Results: In our baseline analysis, early operations provided a small survival advantage (0.14 QALYs) at a small incremental cost of $1510. Thus, despite a small survival benefit, early surgery appeared cost-effective ($10,800/QALY). The small cost differential resulted from the large proportion of patients who underwent surveillance, who eventually underwent AAA repair, and therefore incurred the cost of the surgical procedures. The survival advantage and cost-effectiveness of early operation increased with lower operative mortality, younger age, and larger AAA diameter.Conclusion: Despite the negative conclusions of the UK trial, early surgery may be cost-effective for patients with small AAAs, particularly younger patients (<72 years of age) with larger AAAs (≥4.5 cm). Because the gains in life expectancy are relatively small, however, clinical decision making should be strongly guided by patient preferences.