A total of 930 cases of ST-segment elevation myocardial infarction were prospectively recorded in the Florence health district. Factors influencing survival or those associated with use of revascularization (percutaneous coronary intervention, 91%) were identified through multivariate analyses (Cox and logistic regression, respectively). The independent protective effect of coronary reperfusion therapy (CRT) was evident at 36 months (39% reduction in the risk of death). After adjusting for all multivariate predictors, CRT use was 63% less likely at age 85 years and older than at under 65 years (p<0.001). Since beyond advancing age, comorbidity appeared to be associated with a reduced chance of CRT, three chronic comorbidity score categories were calculated using information on past medical history. Increased 1-year mortality in patients with higher comorbidity score categories derives, at least in part, from underutilization of CRT. Results confirm that although they might potentially benefit from CRT during ST-segment elevation myocardial infarction, older and frail patients are excluded from CRT, even when eligible.