Application of the TIMI risk score for ST-Elevation MI in the National Registry of Myocardial Infarction 3

Context The Thrombolysis in Myocardial Infarction (TIMI) risk score for ST-elevation myocardial infarction (STEMI) is a simple integer score for bedside risk assessment of patients with STEMI Developed and validated in multiple clinical trials of fibrinolysis, the risk score has not been validated in a community-based population. Objective To validate the TIMI risk score in a population of STEMI patients reflective of contemporary practice. Design, Setting, and Participants The risk score was evaluated among 84029 patients with STEMI from the National Registry of Myocardial Infarction 3 (NRMI 3), which collected data on consecutive patients with myocardial infarction (MI) from 1529 US hospitals between April 1998 and June 2000. Main Outcome Measures Ability of the TIMI risk score to correctly predict risk of death in terms of model discrimination (c statistic) and calibration (agreement of predicted and observed death rates). Results Patients in NRMI 3 tended to be older, to be more often female, and to have a history of coronary disease more often than those in the derivation set. Forty-eight percent received reperfusion therapy. The TIMI risk score revealed a significant graded increase in mortality with rising score (range, 1.1%-30.0%; P<.001 for trend). The risk score showed strong prognostic capacity overall (c=0.74 vs 0.78 in derivation set) and among patients receiving acute reperfusion therapy (c=0.79). Predictive behavior of the risk score was similar between fibrinolytic-treated patients (n=23960, c=0.79) and primary percutaneous coronary intervention patients (n=15348; c=0.80). In contrast, among patients not receiving reperfusion therapy, the risk score underestimated death rates and offered lower discriminatory capacity (c=0.65). Conclusions Sufficiently simple to be practical at the bedside and effective for risk assessment across a spectrum of patients, the TIMI risk score may be useful in triage and treatment of patients with STEMI who are treated with reperfusion therapy.