Analysis of cost effectiveness of screening Danish men aged 65 for abdominal aortic aneurysm

Abstract

Objective: To assess the cost effectiveness of screening men aged 65 for abdominal aortic aneurysm.

Design: Cost effectiveness analysis based on a probabilistic, enhanced economic decision analytical model from screening to death.

Population and setting: Hypothetical population of men aged 65 invited (or not invited) for ultrasound screening in the Danish healthcare system.

Data sources: Published results from randomised trials and observational epidemiological studies retrieved from electronic bibliographic databases, and supplementary data obtained from the Danish Vascular Registry.

Data synthesis: A hybrid decision tree and Markov model was developed to simulate the short term and long term effects of screening for abdominal aortic aneurysm compared with no systematic screening on clinical and cost effectiveness outcomes. Probabilistic sensitivity analyses using Monte Carlo simulation were carried out. Results were presented in a cost effectiveness acceptability curve, an expected value of perfect information curve, and a curve showing the expected (net) number of avoided deaths from abdominal aortic aneurysm over time after the introduction of screening. The model was validated by calibrating base case health outcomes and expected activity levels against evidence from the recent Cochrane review of screening for abdominal aortic aneurysm.

Results: The estimated costs per quality adjusted life year (QALY) gained discounted at 3% per year over a lifetime for costs and QALYs was pound43 485 (euro54,852; $71,160). At a willingness to pay threshold of pound30,000 the probability of screening for abdominal aortic aneurysm being cost effective was less than 30%. One way sensitivity analyses showed the incremental cost effectiveness ratio varying from pound32,640 to pound66,001 per QALY.

Conclusion: Screening for abdominal aortic aneurysm does not seem to be cost effective. Further research is needed on long term quality of life outcomes and costs.

Fig 1 Decision analytical model of screening for abdominal aortic aneurysm compared with no systematic screening

Fig 2 Cost effectiveness acceptability curve of screening for abdominal aortic aneurysm in hypothetical population of 10 000 men aged 65

Fig 3 Expected value of perfect information (EVPI) for hypothetical population of 250 000 men aged 65

Fig 4 Simulation of expected (net) number of avoided deaths from abdominal aortic aneurysm after screening 15 consecutive cohorts of 10 000 men aged 65. Expected (net) number of avoided deaths are calculated as the difference in total expected number of deaths due to ruptured abdominal aortic aneurysm and deaths due to elective surgery under the two alternatives