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=23 960; 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.