Assessing the costs and benefits of medical research: the diabetic retinopathy study.

Significant amounts of scarce resources are devoted to medical research, but there have been few attempts to assess whether the benefits to society of these investments exceed the costs. A method for undertaking such an assessment has been developed and applied retrospectively to the Diabetic Retinopathy Study, a major clinical trial funded by the National Eye Institute from 1972-1981. It was estimated that the trial, which cost $10.5 million, generated a net saving of $2816 million to society ($231 million when the costs of lost production are excluded) (1982 prices) and a gain to patients of 279,000 vision years. This approach could be applied prospectively in considering priorities for medical research, in conjunction with traditional criteria such as the scientific merit of the proposal and the capabilities of the investigators. The key factors affecting the economic returns from medical research are the prevalence, incidence and economic burden of the disease in question, the costs and effectiveness of the medical intervention concerned, the likely impact of the clinical trial on clinical practice and the likely timespan of benefits from knowledge obtained during the trial.