Prognostic Effect of Changes in Physical Function Over Prior Year on Subsequent Mortality and Long-Term Nursing Home Admission

ObjectivesTo evaluate the prognostic effect of changes in physical function at different intervals over the prior year on subsequent outcomes after accounting for present function. DesignProspective longitudinal study. SettingGreater New Haven, Connecticut, from March 1998 to January 2006. ParticipantsCommunity-living persons aged 71 and older who completed an 18-month comprehensive assessment (N=658). MeasurementsDisability in 13 activities of daily living, instrumental activities of daily living, and mobility activities was assessed at the 18-month comprehensive assessment and at 12, 6, and 3 months before 18 months. Time to death and long-term nursing home admission, defined as 3 months and longer, were ascertained for up to 5 years after 18 months. ResultsIn the bivariate models, disability at 18 months and change in disability between 18 months and each of the 3 prior time-points (12, 6, 3 months) were significantly associated with time to death. The risk of death, for example, increased by 24% for each 1-point increase in 18-month disability score (on a scale from 0 to 13) and by 22% for each 1-point change in disability score between 18 months and prior 12 months (on a scale from -13 to 13). In a set of multivariable models with and without covariates, the associations were maintained for 18-month disability but not for change in disability between 18 months and each of the 3 prior time-points. The results were comparable for time to long-term nursing home admission except that 2 of the associations were not statistically significant. ConclusionWhen evaluating risk of adverse outcomes, such as death and long-term nursing home admission, an assessment of change in physical function at different intervals over the prior year, although a strong bivariate predictor, did not provide useful prognostic information beyond that available from current level of function.