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
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 84 029 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).
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 = 15 348; 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).
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