Developing a summary measure of medical status.

Health status surveys and assessments typically obtain detailed information on specific physical health conditions. While such specific details are important, it is frequently also valuable to have a summarized evaluation of medical conditions which can be used to compare subjects, or for statistical analyses. Using data from the Duke Established Populations for Epidemiologic Studies of the Elderly survey, we indicate how to obtain a weighted sum of chronic medical conditions. Like the sum of the same conditions, it explains variance in selected measures of health service use and health status, in some instances making a contribution beyond that of the summed measure. It is a significantly better predictor of mortality within six years.