Estimate of disease prevalence using drug consumption data.

A simple method is presented to estimate the prevalence for chronic diseases treated with drugs that are specific to the disease and must be taken continuously. Data required for the computations involve the total amount of drugs sold in a given region and the mean intake of these drugs, which can be based on the defined daily doses, the prescribed daily doses, or the consumed daily doses. The prevalence of the studied disease is the most accurate using the consumed daily doses estimated in a sample of patients with the disease of interest. Data on diabetes mellitus and intraocular hypertension collected in Belgium in 1990 and 1992, respectively, were used to illustrate the applicability of this quick and inexpensive method. For these two diseases, the precision of the prevalence estimated with the present method is comparable to that achieved with conventional cross-sectional studies, but at a lower cost.