Validation of the updated logistic clinical SYNTAX score for all-cause mortality in the GLOBAL LEADERS trial

Aims: The aim of this study was the external validation of the updated logistic clinical SYNTAX score for two-year all-cause mortality after PCI in the GLOBAL LEADERS trial. Methods and results: The GLOBAL LEADERS trial was an investigator-initiated, prospective randomised, multicentre, open-label trial comparing two strategies of antiplatelet therapy in 15,991 patients undergoing PCI. As a predefined analysis, we studied the first 4,006 consecutive patients enrolled between July 2013 and April 2014 for whom the anatomic SYNTAX scores were calculated by an independent core lab. The updated logistic clinical SYNTAX score was available in 3,271 patients. Patients were divided into quintiles according to the score. The C-statistic of the updated logistic clinical SYNTAX score for two-year all-cause mortality was 0.71 (95% confidence interval [CI]: 0.64-0.77). The updated logistic clinical SYNTAX score identified patients at very high risk for two-year all-cause mortality after PCI. Although it systematically overestimated two-year all-cause mortality, predicted and observed two-year all-cause mortality in the majority of the patients (four out of five quintiles) were in agreement. Conclusions: Overall discrimination for two-year all-cause mortality of the updated logistic clinical SYNTAX score is either borderline acceptable or possibly helpful. Calibration in the majority of patients is appropriate. The score is potentially useful in selecting enriched high-risk populations.