Change in Frailty and Risk of Death in Older Persons

Abstract

The authors developed and validated a continuous composite measure of frailty and examined its rate of change in 832 older persons with annual evaluations for up to 8 years. In generalized estimating equation models adjusted for age, sex, and education, there was a significant increase in frailty during follow-up. In a proportional hazards model controlling for age, sex, education, and baseline frailty, each 1-unit increase in annual change in frailty was associated with an almost 5 times the risk of mortality. Using a continuous measure, the authors document that frailty is progressive in some older persons and that its rate of progression is associated with mortality.

Acknowledgments

This research was supported by National Institute on Aging grants R01AG17917 and R01AG24480, the Illinois Department of Public Health, and the Robert C. Borwell Endowment Fund. The authors are indebted to the residents from the following groups participating in the Rush Memory and Aging Project: Fairview Village, Wyndemere, Luther Village, The Holmstad, Windsor Park Manor, Covenant Village, Bethlehem Woods, King-Bruwaert House, Friendship Village, Mayslake Village, The Moorings, Washington Jane Smith, Victory Lakes, Village Woods, Franciscan Village, Victorian Village, The Breakers of Edgewater, The Oaks, St. Paul Home, The Imperial, Frances Manor, Peace Village, Alden Waterford, Marian Village, The Birches, Elgin Housing Authority, Renaissance, Holland Home, Trinity United Church of Christ, St. Andrews-Phoenix, Green Castle, Kingston Manor, Lawrence Manor, Community Renewal-Senior Ministry, Garden House, and the residents of the Chicago metropolitan area.

The authors thank Traci Colvin, Tracy Hagman, and Tracy Nowakowski for project coordination; Barbara Eubeler, Mary Futrell, Karen Lowe Graham, and Pamela Smith for participant recruitment; George Dombrowski and Greg Klein for data management; Liping Gu and Woojeong Bang for statistical programming; and the staff of the Rush Alzheimer's Disease Center and Rush Institute for Healthy Aging.

Notes

*The entire cohort was divided into quintiles based on composite frailty at baseline. The composite measure is constructed so that a more positive value is consistent with more frailty, i.e., poorer performance and a negative value is consistent with less frailty, i.e., better performance. Therefore the fifth quintile has the lowest performance and the first quintile the best performance.

Note. Data are estimate (SE, p value).

*Generalized Estimating Equation Models with age (centered at 80 years), gender (male = 1, female = 0), and education (centered at 14 years). An identity link was used for composite frailty, grip strength, gait, and body composition measures; a logit link was used for fatigue measure. Estimates are the coefficients from the linear predictor, i.e., they are not odds ratios for fatigue. All components are coded such that higher values represent worse function (i.e., higher values mean more frailty, less grip strength, slower gait, more fatigue, and lower body composition).