Geographic variation in the treatment of acute myocardial infarction: the Cooperative Cardiovascular Project

Abstract

Context: Quality indicators for the treatment of acute myocardial infarction include pharmacologic therapy, reperfusion, and smoking cessation advice, but these therapies may not be administered to all patients who could benefit from them.

Objective: To assess geographic variation in adherence to quality indicators for treatment of acute myocardial infarction.

Design: Inception cohort using data from the Health Care Financing Administration Cooperative Cardiovascular Project.

Setting: Acute care hospitals in the United States.

Patients: A total of 186800 Medicare beneficiaries hospitalized for treatment of confirmed acute myocardial infarction from February 1994 through July 1995.

Main outcome measures: Adherence to quality indicators for pharmacologic therapy, reperfusion, and smoking cessation advice for patients judged to be ideal candidates for these therapies. The mean rates of adherence to these quality indicators for the entire United States were determined, and the 20th and 80th percentiles of the age- and sex-adjusted rates for each of 306 hospital referral regions were contrasted (mean rate [20th-80th percentiles]).

Results: Aspirin was used frequently both during hospitalization (86.2% [82.6%-90.1%]) and at discharge (77.8% [72.5% -83.9%]). Calcium channel blockers were withheld from most patients with impaired left ventricular function (81.9% [73.6%-90.8%]). Lower rates were seen in the use of angiotensin-converting enzyme inhibitors at discharge (59.3% [49.2%-69.2%]); reperfusion, using thrombolytic therapy or coronary angioplasty (67.2% [59.8%-75.1%]); prescription of beta-blockers at discharge (49.5% [35.8%-61.5%]); and for smoking cessation advice (41.9% [32.8%-51.3%]).

Conclusions: Substantial geographic variation exists in the treatment of patients with acute myocardial infarction, and these gaps between knowledge and practice have important consequences. Therapies with proven benefit for AMI are underused despite strong evidence that their use will result in better patient outcomes.