A cost-benefit analysis of a cardiovascular disease prevention trial, using folate supplementation as an example.

OBJECTIVES

This study illustrates a cost-benefit analysis of clinical trial design, using as an example a trial of folate supplementation to prevent cardiovascular disease.

METHODS

Bayesian statistical and decision-analytic techniques were used to estimate the cost-benefit and sample size of a placebo-controlled trial of folate targeted to US citizens, aged 35 to 84 years, with elevated serum homocysteine levels. The main end point is event-free survival (i.e., survival without new ischemic heart disease or stroke) at 5 years.

RESULTS

Because the screening cost and annual cost and inconvenience of taking folate is small compared with the consequences of stroke, ischemic heart disease, or death, the increase in 5-year event-free survival with folate that should compel the use of folate is just 1.1%. The sample size per group needed to establish this level of folate's medical effectiveness is estimated to be 17310. Such a trial would provide an expected societal cost-benefit savings exceeding $11 billion within 15 years.

CONCLUSIONS

This study illustrates how Bayesian methods may help in assessing the societal cost-benefit consequences of proposed disease prevention trials, deciding which trials are worth sponsoring, and designing cost-effective trials.