Ambulatory care classification systems.

This article describes several methods of classifying resources used in ambulatory care into isoresource consumption groups. These methods are based on resources used by patients during a year, rather than on resources used in a single visit. Variables used to partition patient-year charges into isoresource consumption groups are age, race, number of health problems or major diagnostic categories addressed, number of medications or categories of medications prescribed, and indexes developed to reflect resources used by diagnostic categories during a patient-year. Confirmation in other settings of the findings of this study would have important implications for the design of prospective payment plans for ambulatory care.