A risk score system for predicting adverse outcomes and magnitude of benefit with glycoprotein IIb/IIIa inhibitor therapy in patients with unstable angina pectoris

Clinical outcomes of patients with unstable angina are variable. We sought to identify predictors of adverse clinical outcomes in patients with unstab le angina and to investigate whether these factors would predict the magnit ude of benefit achieved with platelet glycoprotein Ilb/IIIa inhibition. We analyzed 20 variables in the 1,915 patients enrolled in the Platelet Recept or Inhibition for Ischemic Syndrome Management in Patients Limited by Unsta ble Signs and Symptoms trial. Five independent predictors were identified: age > 65 years, prior coronary artery bypass grafting, antecedent aspirin u se, antecedent beta -blocker use, and ST depressions on the presenting elec trocardiogram. A risk score system was created using these predictors in wh ich patients were assigned 1 point for the presence of each risk factor. Th ere was a progressive increase in the rate of the composite end point of de ath, myocardial infarction, or refractory ischemia at 7 days with an increa sing number of risk factors. For patients treated with heparin alone, the c omposite end point event rate was 6.5% in the group with 0 or 1 predictor, 14.6% in the group with 2 predictors, 22.7% in the group with 3 predictors, and 37.1% in the group with 4 or 5 predictors (p < 0.00001). When dividing patients into low- (0 or 1 point), medium(2 or 3 points), and high-risk (4 or 5 points) groups, the addition of tirofiban to heparin therapy was asso ciated with no significant benefit in the low-risk group, a 5.2% absolute r eduction in the medium-risk group (p = 0.05), and a 16% absolute reduction in the high-risk group (p = 0.0055). Thus, we have developed a risk score s ystem using 5 variables that can be used to identify patients at high risk for death and cardiac ischemic events and who experience the greatest benef it from the addition of a glycoprotein IIb/IIIa inhibitor to their treatmen t regimen. (C) 2001 by Excerpta Medica, Inc.