Abstract
Background:
Cardiorespiratory fitness (CRF) is a powerful predictor of mortality, but its incremental value for improving clinical risk classification beyond traditional cardiovascular risk factors remains incompletely defined. We evaluated whether the addition of CRF improves 10-year mortality risk prediction using contemporary reclassification metrics.
Methods:
We analyzed 562,234 adults from a clinical exercise testing cohort with complete covariate data. CRF was assessed by peak metabolic equivalents (METs) achieved during treadmill testing and dichotomized as fit versus unfit, with unfit defined as the least fit quintile (
Results:
During a mean follow-up of 10.2±5.1 years, CRF was independently associated with mortality, with each 1-MET higher CRF associated with a 16% lower hazard of death (hazard ratio 0.84; 95% CI 0.838–0.842; p
Conclusions:
CRF significantly improves 10-year mortality risk prediction beyond traditional cardiovascular risk factors and meaningfully enhances individual-level risk stratification. Incorporation of CRF into routine clinical risk assessment frameworks should be considered.