Cost-Effectiveness Analysis of Active Surveillance for Small Asymptomatic Intracranial Aneurysms

Abstract

Abstract INTRODUCTION The current recommended management strategy for small, asymptomatic unruptured anterior circulation aneurysms (UIAs) is active surveillance utilizing serial magnetic resonance angiography (MRA). Our objective was to determine the cost-effectiveness of active surveillance via MRA, immediate surgery, and watchful waiting for small UIAs. METHODS We developed a Markov cost-effectiveness model simulating a cohort of patients with small (<7 mm) UIAs diagnosed at age 50-yr who were treated with active surveillance via MRA, immediate surgery, or watchful waiting. Model inputs (eg risk of aneurysm growth, rupture rate, treatment complications, etc) were abstracted from peer-reviewed literature. Outcomes were quality-adjusted life-years (QALY), lifetime medical costs (2015 US$), and incremental cost-effectiveness ratios (ICER). Cost-effectiveness analysis as well as deterministic and probabilistic sensitivity analyses were performed. Willingness to pay (WTP) threshold was $100,000/QALY. RESULTS At a WTP of $100,000/QALY, immediate surgical treatment was the most cost-effective management strategy for small UIAs; ICER of $43,880 relative to active surveillance. Sensitivity analyses demonstrated immediate surgery was the preferred strategy if rupture rate was >0.1%/yr and if diagnosis age was <70 yr. Active surveillance became the preferred strategy if surgical complication risk was >11% and if diagnosis age was >70-yr. MRA surveillance interval did not significantly impact cost-effectiveness (surveillance frequency range 6 mo-10 yr). Probabilistic sensitivity analysis demonstrated that at a WTP of $100,000/QALY immediate surgery was the most cost-effective strategy in 64% of iterations (compared to active surveillance in 34%, and watchful waiting in 1.4%). CONCLUSION Immediate surgical treatment is a reasonable and cost-effective strategy for initial management of small UIAs. The cost-effectiveness of immediate surgery is highly sensitive to age at diagnosis, rupture rate, and probability of surgical complication. As there are wide published ranges for rates of rupture and surgical complications, individual lesion characteristics and surgeon-specific complication metrics should be considered in counseling patients.