research demonstrating a lower rate of use of cardiac procedures among blacks with private insurance or Medicare compared with whites who are similarly insured (Wenneker and Epstein, 1989). White Medicare recipients are three times more likely than black Medicare recipients to receive coronary artery bypass graft surgery and angioplasty. White Medicare recipients are also more likely than blacks to have magnetic resonance imaging (MRI) scans rather than the less costly computed tomography (CT) scans (Boutwell and Mitchell, 1991).

Standards for Appropriate Use. Increasing attention is being paid to outcomes research and the development of clinical practice guidelines. As techniques become established for determining the appropriateness of use of certain medical procedures, interpreting differences in use among subpopulations will become easier. For example, these techniques will allow us to distinguish problems in access from overutilization of services by specific populations.

Improved Data Availability. Researchers who are seeking improvements in clinical data bases for use in outcomes research should work with those interested in access research to determine whether there are mutually beneficial opportunities for enhancing these data bases. An issue of interest to both groups, for instance, might be the addition of information to the discharge abstract, which would help to measure severity more accurately.

For the purposes of this indicator, "avoidable hospitalizations" are those that might not have occurred had the patient received effective, timely, and continuous outpatient (ambulatory) medical care for certain chronic disease conditions. Although hospital admission rates are generally a utilization measure, they are used here as a proxy for health conditions that have deteriorated to the point where hospitalization is required.

Ongoing medical management can effectively control the severity and progression of a number of chronic diseases, even if the diseases themselves cannot be prevented. An advanced stage of a chronic disease that requires hospitalization may indicate the existence of one or more barriers to access to the personal health care system. Thus, hospital admissions for certain conditions are a potentially useful indicator of the performance of the ambulatory health care system. High rates of admissions for conditions related to treatable chronic diseases in particular may provide indirect evidence of serious patient access problems or deficiencies in outpatient management.