The RAPID-10 score: a new risk score from the retrospective analysis of maximal workload predictors of survival in ischemic heart disease at 10 years

Abstract Background Cardiac stress testing (CST) is valuable in the management of ischemic heart disease (IHD). The FIT Treadmill Score from the largest study of physical fitness - the Henry Ford Exercise Testing Project– is among the most accurate model in predicting survival. Recent data from our group showed that workload-indexed blood pressure (WPBR) is a strong and independent predictor of survival in IHD, a variable not included in the FIT score. Purpose Therefore, our purpose was to create a new score that includes WBPR and other maximal exercise variables and compare with the FIT score. Methods The study comprised 713 patients with IHD that performed CST on treadmill between 2009-2010. The follow-up period was 10±2 years. WBPR (systolic blood pressure / (metabolic equivalent of task(met)-1)) and the FIT score were calculated at baseline as previously described 1,2. Continuous variables were fitted using linear and nonlinear regressions. Time-to-event (death and major adverse cardiovascular events (MACE)) were correlated with baseline variables through logistic regression models. The new score was built using a backward stepwise regression of clinical and CST variables. Score accuracy was assessed with receiver operating characteristic (ROC) curves. Event-free survival analyses used Cox regression models. Data are: mean ± standard deviation; 95% confidence interval (CI) for hazard ratios (HR); significance level p