Sex-Specific Risk Scores to Identify All-Cause Mortality Risk
Do sex-specific risk scores better estimate all-cause mortality among men and women?
Data from the Cleveland Clinic Foundation (collected from January 1, 2000–December 31, 2010), and 49,278 patients seen at the Henry Ford Hospital (collected from January 1, 1991–December 31, 2009) were used for this retrospective analysis. All patients were 18 years or older and underwent exercise treadmill testing. The Cleveland Clinic cohort was divided randomly into derivation and validation samples, and separate risk scores were developed for men and women. Net reclassification, C-statistics, and integrated discrimination improvement were used to compare the sex-specific risk scores with other tools that have all-cause mortality as the outcome. Discrimination and calibration were also evaluated with these sex-specific risk scores in the Henry Ford Hospital cohort.
A total of 59,877 patients (59.4% men; 40.5% women) seen at Cleveland Clinic and 49,278 patients seen at Henry Ford Hospital (52.5% men; 47.4% women) were included in this analysis. Median age of the Cleveland Clinic patients was 54 years. Median age for the Henry Ford Hospital patients was 54 years. A total of 2,521 deaths occurred over a median of 7 years of follow-up in the Cleveland Clinic cohort and 6,643 deaths occurred in the Henry Ford Hospital cohort over a median of 10.2 years of follow-up. C-statistics for the sex-specific risk scores in the Cleveland Clinic validation sample were higher (0.79 in women and 0.81 in men) than C-statistics using other tools in women (0.70 for Duke treadmill score; 0.74 for Lauer nomogram) and men (0.72 for Duke treadmill score; 0.75 for Lauer nomogram). Net reclassification and integrated discrimination improvement were superior with the sex-specific risk scores, mostly owing to correct reclassification of events. The sex-specific risk scores in the Henry Ford Hospital cohort demonstrated similar discrimination (C-statistic, 0.78 for women and 0.79 for men), and calibration was reasonable.
The investigators concluded that sex-specific risk scores better estimate mortality in patients undergoing exercise treadmill testing. In particular, these sex-specific risk scores help to identify patients at the highest residual risk in the present era.
The combination of two large cohorts supports the use of sex-specific risk scores to identify patients at risk for all-cause mortality.
Clinical Topics: Prevention
Keywords: Calibration, Exercise Test, Mortality, Nomograms, Primary Prevention, Risk
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