The society of thoracic surgeons 30-day predicted risk of mortality score also predicts long-term survival

Abstract

Background: The Society of Thoracic Surgeons Predicted Risk of Mortality (PROM) score is a well-validated predictor of 30-day mortality after cardiac procedures. This study investigated the ability of PROM to predict longer-term survival.

Methods: From January 1, 1996, to December 31, 2009, 24,222 patients with PROM scores underwent cardiac procedures at an academic center. Long-term all-cause mortality was determined from the Social Security Death Index. Logistic and Cox survival regression analyses evaluated the long-term predictive utility of the PROM. Area under the receiver operator characteristic curve measured the discrimination of PROM at 1, 3, 5, and 10 years. Kaplan-Meier curves were stratified by quartiles of PROM risk to compare long-term survival. All analyses were performed for the whole sample and for 30-day survivors.

Results: The overall 30-day mortality was 2.78% (674 of 24,222). PROM predicted 30-day mortality extremely well (area under the receiver operator characteristic, 0.794) and predicted longer-term survival almost as well. Among all patients and 30-day survivors, area under the receiver operator characteristic values for PROM at 1, 3, 5, and 10 years were remarkably similar to the 30-day end point for which PROM is calibrated. PROM was highly predictive of Kaplan-Meier survival for patients surviving beyond 30 days. Among 30-day survivors, each percent increase in PROM score was associated with a 9.6% increase (95% confidence interval, 9.3% to 10.0%) in instantaneous hazard of death (p<0.001).

Conclusions: The PROM algorithm accurately predicts death at 30-days and during 14 years of follow-up with almost equally strong discriminatory power. This may have profound implications for informed consent and for longitudinal comparative effectiveness studies.