Prognostic role of insulin resistance as assessed by homeostatic model assessment index in the acute phase of myocardial infarction in nondiabetic patients submitted to percutaneous coronary intervention.

BACKGROUND AND OBJECTIVES: Little information is available on the relation between insulin resistance and acute myocardial infarction.
METHODS: In 253 consecutive nondiabetic patients with ST elevation myocardial infarction (STEMI) submitted to percutaneous coronary intervention, we assessed the prevalence of insulin resistance by homeostatic model assessment (HOMA) index and its prognostic role in early and late mortality.
RESULTS: Insulin resistance was detectable in 52.9% of patients. Anterior STEMI was more frequent in insulin-resistant patients (P = 0.040), who showed higher values of probrain natriuretic peptide (P = 0.010), creatinine (P < 0.001), creatinine phosphokinase and creatinine phosphokinase-MB (MB, isoenzyme present in the myocardium; P = 0.016 and P = 0.003, respectively). At backward stepwise logistic regression analysis, the following variables were independent predictors for intra-intensive cardiac care unit mortality: HOMA index [hazard ratio 1.40; 95% confidence interval (CI) 1.02-1.95; P = 0.049]; C-peptide (hazard ratio 3.14; 95% CI 1.40-24.80; P = 0.001) and lactic acid (hazard ratio 2.50; 95% CI 1.41-4.44; P = 0.002). At long-term follow-up (Cox regression analysis), neither fasting glycaemia nor HOMA index resulted in predictors for mortality.
CONCLUSION: In nondiabetic STEMI patients submitted to percutaneous coronary intervention, insulin resistance, as assessed by HOMA index, is quite common and helps in the early prognostic stratification, as it represents an independent predictor of in-hospital mortality.