Economic evaluation of screening for abdominal aortic aneurysm in elderly men in Hong Kong

Abstract

Background: Abdominal aortic aneurysm (AAA) is a degenerative disease prevailing in men aged 65 years and above. Most AAA patients are asymptomatic until the disease develops to a very severe stage. Systematic screening could detect AAA in an early stage and early treatment is therefore provided to prevent AAA rupture and reduce AAA-related death. Ultrasonography is a recommended tool for AAA screening, which has been widely used in several western countries. Hong Kong currently has not introduced this screening programme yet. The present study attempts to investigate the health related quality of life (HRQOLO) of AAA patients in Hong Kong and then examine whether a systematic screening in elderly men in Hong Kong is cost effective compare with current practice (Non-screening strategy)

Methods: Firstly, a questionnaire based study was conducted in a local university-affiliated vascular tertiary referral center targeting on AAA patients. Quality of life data was collected by a face-to-face interview using the Medical Outcomes Study Short-Form-36 Health Survey (SF-36). A controlled group was obtained from a large local population study matched by gender and age to the AAA group. The SF-36 scores were compared between the two groups; a stepwise multivariate regression analysis was conducted to show the association between the disease and the SF-36 scores.

Secondly, a cost effectiveness analysis based on a Markov model was conducted to compare the screening strategy against non-screening practice. Incremental cost effectiveness ratios (ICER) was adopted as the rule of decision making. One-way sensitivity analysis and probabilistic analysis were performed to explore the uncertainty around the parameters.

Results: 172 out of 252 patients participated the interview, among which 80% were aged 65 years or above, and 85% were males. Around 80% patients were detected incidentally. Comparing with the age and gender matched control group, AAA patients had an impaired HRQOL The disease adversely affected mental health summary of AAA patients.

Under the discount rate of 3% on costs and effectiveness, the incremental costs of systematic screening against non-screening is HK$3,710.3; and the incremental life year gained and quality adjusted life year (QALY) gained are 0.024 and 0.014, respectively. The ICER is HK$ 151,070.1 per life year gained and HK$ 268,897.6 per QALY gained, which is cost effective under the threshold of one GDP per capita (HK$285,403) for one QALY gained.

Conclusion: The economic evaluation based on the Markov model indicated systematic screening for AAA among elderly men in Hong Kong is cost effective. Government in Hong Kong should consider introducing the screening programme when resource is available.