Abstract 14392: Prediction of 30-Year Risk for CVD Mortality by Fitness and Risk Factor Levels: The Cooper Center Longitudinal Study
Background: Long-term risk estimation has been proposed as an adjunct to short-term risk estimation. To our knowledge, currently available long-term risk prediction tools do not incorporate physical fitness. Therefore, we sought to create a 30-year risk prediction tool for cardiovascular disease (CVD) death adjusted for competing risks that incorporates baseline measures of traditional risk factors and fitness.
Methods: We included 16,533 participants from the Cooper Center Longitudinal Study (82% men) objectively measured fitness and other traditional risk factors and a minimum follow-up time of 25 years. Fitness was measured by Balke protocol and categorized according to treadmill time into non-fit and fit categories for both men and women. Participants were followed through 2006 for CVD and non-CVD death determined from the National Death Index. The 30-year risk estimate for CVD death adjusted for competing risk of non-CVD death was estimated using a modified Cox model. Measures of discrimination and calibration were used to assess model performance.
Results: After more than 400,000 person years of follow-up, there were 781 CVD deaths. The 30-year model demonstrated good discrimination (women: C=0.78; men: C=0.82) and good calibration (Nam-D'Agostino χ2 statistic: p = NS). The presence of low fitness was associated with an increased 30-year risk of CVD death across all age, sex, and risk factor categories. Representative data are shown for the association between fitness and risk factor combinations measured at age 50 and 30-year risk for CVD death in men and women, with low fit defined as the bottom 20th percentile treadmill time for age and sex.
Conclusion: The present study provides a novel 30-year risk prediction model for CVD death that incorporates fitness and traditional risk factors and adjusts for competing non-CVD death. This tool could represent a useful adjunct to existing short-term risk equations.
- © 2011 by American Heart Association, Inc.