Predicting Mortality up to 14 Years Among Community-Dwelling Adults Aged 65 and Older

Abstract

Objectives: Extended validation of an index predicting mortality among community-dwelling US older adults.

Design/setting: Examination of the performance of a previously developed index in predicting 10- and 14-year mortality among respondents to the 1997-2000 National Health Interview Surveys (NHIS) using the original development and validation cohorts. Follow-up mortality data are now available through 2011.

Participants: 16,063 respondents from the original development cohort and 8,027 respondents from the original validation cohort. All participants were community dwelling and ≥65 years old.

Measurements: We calculated risk scores for each respondent based on the presence or absence of 11 factors (function, illnesses, behaviors, demographics) that make up the index. Using the Kaplan Meier method, we computed 10- and 14-year mortality estimates for the development and validation cohorts to examine model calibration. We examined model discrimination using the c-index.

Results: Participants in the development and validation cohorts were similar. Participants with risk scores 0-4 had 23% risk of 14-year mortality whereas respondents with risk scores (13+) had 89% risk of 14-year mortality. The c-index of the model in both cohorts was 0.73 for predicting 10-year mortality and 0.72 for predicting 14-year mortality. Overall, 18.4% of adults 65-74 years and 60.2% of adults ≥75 years have >50% risk of mortality in 10 years.

Conclusions: Our index demonstrated excellent calibration and discrimination in predicting 10- and 14-year mortality among community-dwelling US adults ≥65 years. Information on long-term prognosis is needed to help clinicians and older adults make more informed person-centered medical decisions and to help older adults plan for the future.

Keywords: life expectancy; mortality prediction; older adults; prevention.