Validation of the Thrombolysis In Myocardial Infarction (TIMI) risk index for predicting early mortality in a population-based cohort of STEMI and non-STEMI patients

Abstract

The Thrombolysis In Myocardial Infarction (TIMI) risk index for the prediction of 30-day mortality was developed and validated in patients with ST-segment elevation myocardial infarction (STEMI) who were being treated with thrombolytics in randomized clinical trials. When tested in clinical registries of patients with STEMI, the index performed poorly in an older (65 years and older) Medicare population, but it was a good predictor of early death among the more representative population on the National Registry of Myocardial Infarction-3 and -4 databases. It has not been tested in a population outside the United States or among non-STEMI patients. The TIMI risk index was applied to the Enhanced Feedback for Effective Cardiac Treatment (EFFECT) study cohort of 11,510 acute MI patients from Ontario. The model's discriminatory capacity and calibration were tested in all patients and in subgroups determined by age, sex, diagnosis and reperfusion status. The TIMI risk index was strongly associated with 30-day mortality for both STEMI and non-STEMI patients. The C statistic was 0.82 for STEMI and 0.80 for non-STEMI patients, with overlapping 95% CI. The discriminatory capacity was somewhat lower for patients older than 65 years of age (0.74). The model was well calibrated. The TIMI risk index is a simple, valid and moderately accurate tool for the stratification of risk for early death in STEMI and non-STEMI patients in the community setting. Its routine clinical use is warranted.