Predictive Capacity of Frailty Phenotype Toward Patterns of Disability Identified Using Latent Class Analysis

Abstract

Objectives: Frailty phenotype (FP) has low sensitivity toward the identification of older people who will lose 1 or more activities of daily living. Nevertheless, the definition of disability in terms of activities of daily living may not resemble the pattern of functional impairment occurring during aging. The aim of this study was to examine the discriminative capacity of the FP toward the identification of patterns of disabilities in an extended list of tasks, identified among community-dwelling older people.

Design: Longitudinal cohort study.

Setting and participants: We included 997 persons age 65 years and older selected from the Invecchiare in Chianti (InCHIANTI) Study population.

Measures: Using latent class analysis, we assessed the pattern of 3-year changes in 24 functional tasks. Then, we calculated the discriminative capacity of the FP for each pattern of disability. Analyses were stratified by sex.

Results: In both men and women, we recognized 3 classes: stable function; disability in complex tasks; and global functional disability. Among women, ability of FP to identify persons in global functional disability showed sensitivity = 0.42, specificity = 0.98, positive and negative predictive values 0.75 and 0.91; the corresponding values for prediction of disability in complex tasks were 0.13, 0.98, 0.68, and 0.75. Similar results were obtained among men.

Conclusions/implications: Over 3 years, older people of the InCHIANTI population remained largely functional stable, some persons developed deficiency in complex tasks, and a minority developed global functional disability. Trying to predict these 3 patterns may be useful for the care of older people in order to promote individualized interventions to reduce the burden of disabilities and their consequences. To this purpose, FP showed a fairly good capacity to identify people at risk of functional decline, but further studies are needed to identify instruments with better prognostic capacity.

Keywords: Frailty; disability; physical performance.