Calf circumference predicts frailty in older adults: the Chinese longitudinal healthy longevity survey

Abstract

Background

Although frailty is a common geriatric syndrome in old adults, a simple method to assess the degree of frailty in a person has not yet been established. In this study we have tried to establish the association between calf circumference (CC) and frailty among older Chinese people.

Methods

We used the data obtained from the 2014 edition of the Chinese Longitudinal Healthy Longevity Survey; 1216 participants aged ≥60 years were included for the study. Body mass index, CC and waist circumference measurement data, and laboratory test results were collected. Frailty status was measured using the frailty index (FI). Participants were then classified into non-frail (FI < 0.25) and frail (FI ≥ 0.25) groups.

Results

There were 874 participants (71.9%) in the non-frail group and 342 (28.1%) in the frail group. The CC was significantly different between the two groups (31.54 ± 4.16 versus 28.04 ± 4.53, P < 0.001). Logistic regression analysis revealed that CC (odds ratio = 0.947, 95% confidence interval: 0.904–0.993, P = 0.023) was an independent impact factor associated with frailty. The CC value of 28.5 cm was considered the best cut-off value in women with area under the curve (AUC) was 0.732 (P < 0.001) and 29.5 cm in men with AUC was 0.592 (P = 0.004);We created a simple prediction model for frailty that included age,sex and CC:

$$\textrm{Logit}(P)=-9.756+0.123\ast \textrm{Age}-0.512\ast \textrm{Sex}\left(\textrm{man}=1,\textrm{woman}=0\right)-0.053\ast \textrm{CC},$$

P = e^logit(P) /1 + e^logit(P), and AUC is 0.849 (P < 0.001).

Conclusions

CC is a convenient and predictable marker of frailty in older adults.