VARIATIONS IN THE MANAGEMENT OF ACUTE MYOCARDIAL-INFARCTION - IMPORTANCE OF CLINICAL MEASURES OF DISEASE SEVERITY

OBJECTIVE: To determine the extent to which resource use for patients hospitalized with acute myocardial infarction varies with clinical sta tus, and to see if an observed difference In resource use between two states can be explained by resource use clinically detailed risk adjus tment. DESIGN: Retrospective review of the clinical characteristics an d resource use of 342 patients hospitalized in two states with acute m yocardial infarction. DATA SOURCES: Merged data from three sources: a large, existing research database used in developing the Medicare Mort ality Predictor Score, clinical data abstracted from medical charts sp ecifically for this study, and Medicare Parts A and B claims records. PATIENTS: A probability sample of Medicare patients hospitalized in 19 86 with a diagnosis of acute myocardial infarction and residing in eit her Wisconsin or Washington state; patients dying within 30 days are o versampled. MEASUREMENTS AND MAIN RESULTS: Although patients were clin ically similar in the two states, there were systematic differences in resource use. Patients in Wisconsin spent more than one extra day in the intensive care unit (ICU) (2.8 vs 1.7) as well as more than one ex tra non-ICU day in the hospital (8.0 vs 6.3) than patients in Washingt on. Patients in Wisconsin were also more likely to receive an echocard iogram (35.6% vs 15.8%), nuclear ventriculogram (12.8% vs 4.1%), exerc ise tolerance test (21.5% vs 3.4%), and Holter monitoring (5.4% vs 0%) . (All p < .01.) Differences in utilization were greater for patients at lower risk of dying. The average cost of care was 20.8% higher in W isconsin (p = .01); risk adjustment for clinical and other factors red uced this difference to 11.8%, but did not eliminate it (p = .04). CON CLUSIONS: Patients with acute myocardial infarction vary in resource u se as a function of clinical factors present at admission and occurrin g during the hospital stay; comparisons that do not take account of th ese factors may not discriminate well between providers who care for s icker patients and those who are inefficient. The greater use of resou rces for patients in Wisconsin is at least partially explained by diff erences in clinical characteristics that are not presently captured in administrative data.