The Thrombolysis in Myocardial Infarction risk index predicted in-hospital mortality in non-ST-segment elevation myocardial infarction.

M e t h o d s Design: Analysis of the National Registry of Myocardial Infarction database (April 1998 to October 2002). Setting: > 1500 hospitals in the United States. Patients: 337 192 patients with NSTEMI (without new left bundle-branch block or STEMI) and a heart rate between 50 and 150 beats/min (mean age 72 y, 55% men). Description of prediction guide: The TRI was derived from 12 353 patients with STEMI and was calculated using the equation: TRI = heart rate × (age ÷ 10)2 ÷ systolic pressure (TRI values began with 0, and 10-point intervals were used). The TRI categorized patients into 3 risk groups: high risk = score > 60, intermediate risk = score 30 to 60, and low risk = score 0 to 29. Outcomes: In-hospital mortality.