Predicting late-life disability and death by the rate of decline in physical performance measures

Background: the rate of performance decline may influence the risk of disability or death. Methods: for 4,182 Cardiovascular Health Study participants, we used multinomial Poisson log-linear models to assess the contribution of physical performance in 1998-99, and the rate of performance change between 1992-93 and 1998-99, to the risk of death or disability in 2005-06 in three domains: mobility, upper-extremity function (UEF) and activities of daily living (ADL). We evaluated performance in finger-tapping, grip strength, stride length, gait speed and chair stands separately and together for each outcome, adjusting for age, gender, race and years of disability in that outcome between 1992-93 and 1998-99. Results: participants' age averaged 79.4 in 1998-99; 1,901 died over 7 years. Compared with the lowest change quintile in stride length, the highest quintile had a 1.32 relative risk (RR) of ADL disability (95% CI: 1.16 -1.96) and a 1.27 RR of death (95% CI: 1.07 -1.51). The highest change quintile for grip strength increased the risk of ADL disability by 35% (95% CI: 1.13 -1.61) and death by 31% (95% CI: 1.16 -1.49), compared with the lowest quintile. The annual change in stride length and grip strength also predicted disability in mobility and UEF. Conclusion: performance trajectories independently predict death and disability.