Processes and Outcomes of Care for Diabetic Acute Myocardial Infarction Patients in Ontario

Abstract

OBJECTIVE—To compare the health service utilization and long-term outcomes of acute myocardial infarction (AMI) patients with and without diabetes in Ontario. RESEARCH DESIGN AND METHODS—We examined 25,697 patients from Ontario (6,052 and 19,645 patients with and without diabetes, respectively) who were hospitalized because of AMI between 1 April 1992 and 31 December 1993. Using linked administrative databases, we determined the use of invasive cardiac procedures at 1 year as well as the intensity of specialty follow-up care and use of evidence-based pharmacotherapies (among elderly individuals) within the first 90 days of hospital discharge. Outcomes examined included mortality and recurrent cardiac admissions at 30 days and 5 years post AMI. Multivariable analyses adjusted for sociodemographic and case-mix characteristics, attending physician specialty, and admitting hospital characteristics. RESULTS—Despite being at significantly higher risk for death at baseline, diabetic patients were less likely to be followed-up by a cardiologist (22.2 vs. 25.6%, P < 0.001), to receive myocardial revascularization (12.6 vs. 14.9%, P < 0.001), to receive β-blockers (34.2 vs. 44.0%, P < 0.001), and to receive aspirin therapy (59.7 vs. 63.5%, P < 0.001) after AMI than their nondiabetic counterparts. Diabetes was an important independent predictor of 5-year morbidity (adjusted hazard ratio 1.52, 95% CI 1.45–1.59) and 5-year mortality outcomes (1.57, 1.50–1.63). Variations in processes of care were marginally associated with higher nonfatal complication rates for diabetic patients. CONCLUSIONS—When managing AMI patients with diabetes in Ontario, physician treatment aggressiveness does not correspond appropriately to the baseline risk of patients.