Impact of physical frailty on disability in community-dwelling older adults: a prospective cohort study

Abstract

Objective: To examine the relationship between physical frailty and risk of disability, and to identify the component(s) of frailty with the most impact on disability in community-dwelling older adults.

Design: Prospective cohort study.

Setting: A Japanese community.

Participants: 4341 older adults aged ≥65 living in the community participated in a baseline assessment from 2011 to 2012 and were followed for 2 years.

Main outcome measures: Care-needs certification in the national long-term care insurance (LTCI) system of Japan, type of physical frailty (robust, prefrail, frail) and subitems (slowness, weakness, exhaustion, low activity, weight loss), adjusted for several potential confounders such as demographic characteristics, analysed with Kaplan-Meier survival curves for incidence of disability by frailty phenotype.

Results: During the 2-year follow-up period, 168 participants (3.9%) began using the LTCI system for incidence of disability. Participants classified as frail (HR 4.65, 95% CI 2.63 to 8.22) or prefrail (2.52, 1.56 to 4.07) at the baseline assessment had an increased risk of disability incidence compared with robust participants. Analyses for subitems of frailty showed that slowness (2.32, 1.62 to 3.33), weakness (1.90, 1.35 to 2.68) and weight loss (1.61, 1.13 to 2.31) were related to increased risk of disability incidence. In stratified analyses, participants who were classified as frail and who had lower cognitive function had the highest percentage (30.3%) of disability incidence during the 2 years after baseline assessment.

Conclusions: Physical frailty, even being prefrail, had a strong impact on the risk of future disability. Some components of frailty, such as slowness, weakness and weight loss, are strongly associated with incident disability in community-dwelling older adults.

Keywords: Disability; Frailty; Slowness.

Figure 1

Flow chart of participant recruitment process (LTCI, long-term care insurance; MMSE, Mini-Mental State Examination; OSHPE, Obu Study of Health Promotion for the Elderly).

Figure 2

Incident disability rates during the 2 years after baseline assessment by frailty status and frailty components at baseline Frailty phenotype containing three or more of the following was defined as frail, one or two as prefrail, and none as robust: slowness, weakness, exhaustion, low activity and weight loss.

Figure 3

Kaplan–Meier estimates of cumulative incidence of disability according to frailty status. Frailty phenotype containing three or more of the following was defined as frail, one or two as prefrail, and none as robust: slowness, weakness, exhaustion, low activity and weight loss.

Figure 4

Kaplan–Meier estimates of cumulative incidence of disability according to components of frailty phenotype. Slowness (walking speed) was defined at <1.0 m/s and weakness (handgrip strength) was defined at <26 kg for men and <18 kg for women.

Figure 5

HRs estimate the relative risk of incidence of disability in subgroups defined by sex, age, cognitive function and depressive symptoms in stratified analyses. HRs estimate the relative risk of disability incidence in those classified as prefrail or frail compared with those classified as robust (reference group) in a different subgroup defined by sex, age (74/75 years), cognitive function (Mini-Mental State Examination (MMSE) score 23/24) and depressive symptoms (Geriatric Depression Scale (GDS) score 5/6).