Effect of diabetes mellitus and insulin use on survival after acute myocardial infarction in the elderly (The Cooperative Cardiovascular Project)

Using data from a retrospective cohort study of Medicare beneficiaries hosp italized with an acute myocardial infarction (AMI), we evaluated the role o f diabetes mellitus on 30-day and 1-year mortality. We classified subjects as nondiabetics, diabetics controlled with diet alone, diabetics receiving an oral hypoglycemic agent, and diabetics on insulin at time of admission. We compared baseline admission characteristics of subgroups using chi-squar e and Wilcoxon rank-sum tests and evaluated the effect of each diabetic sta te using sequential logistic models. We identified 80,832 nondiabetic patie nts, 9,862 diet-controlled diabetic patients, 14,664 diabetics receiving an oral hypoglycemic agent, and 12,241 diabetic patients on insulin therapy. Although mean age was similar among the groups, prevalence of hypertension, prior AMI, prior congestive heart failure, and prior revascularization wer e higher among diabetic patients, particularly those taking insulin. Diabet ic patients, particularly those taking insulin, were less likely to receive aspirin and beta blockers and to undergo coronary revascularization. Diabe tic patients had higher 30-day and 1-year mortality than nondiabetic patien ts. After adjustment for demographics, clinical and hospital characteristic s, and treatment strategies, insulin-treated diabetics had the highest risk of mortality, followed by diabetics receiving oral hypoglycemic agents, fo llowed by diet-controlled diabetics. Thus, diabetes is highly prevalent amo ng elderly patients with an AMI. Mortality rates for these patients, partic ularly insulin-using diabetics, are higher than among their nondiabetic cou nterparts. Preventive and therapeutic strategies must be developed to ensur e improved short- and long-term outcomes for elderly patients with diabetes and AMI. (C) 2001 by Excerpta Medico, Inc.