Frailty Index and Sex-Specific 6-Year Mortality in Community-Dwelling Older People: The ActiFE Study

Abstract

Background: Considering that mortality rate and deficit accumulation varies considerably in men and women, we performed a sex-stratified analysis of the association between an estimated frailty index (eFI) with 6-year mortality in the Activity and Function in the Elderly (ActiFE) Study.

Methods: We constructed an eFI using a score (0 [no deficit] to 1 [deficit]) from 32 baseline items representing multiple domains. eFI represents the sum of all scores divided by 32. Cox proportional hazards models adjusted for age, smoking, alcohol intake, and education were used to evaluate this association.

Results: Among 1,204 participants (57.5% men), 18.5% men and 26.0% women were frail (eFI ≥ 0.2) with an age-adjusted mean eFI of 0.13 (95% confidence interval [CI] 0.12, 0.13) and 0.15 (95% CI 0.15, 0.16), respectively. Mortality rate in men (146 deaths) was 34.4 (95% CI 29.3, 40.5) and in women (50 deaths) 15.1 (95% CI 11.5, 19.9) per 1,000 person-years. A 0.1 increment of eFI was associated with a hazard ratio (HR) of 1.94 (95% CI 1.60, 2.35) in men and 2.06 (95% CI 1.58, 2.69) in women. Frail versus nonfrail men and women had a HR of 2.46 (95% CI 1.74, 3.48), and 2.98 (95% CI 1.55, 5.70), respectively. We detected sex differences in the order of the eight common contributor items to the eFI.

Conclusions: We observed a statistically significant difference for the age-adjusted eFI and the frailty prevalence in men and women. However, our analysis does not suggest the presence of effect modification by sex in the association with mortality.

Keywords: Frailty; Frailty index; Mortality; Older persons; Sex-specific.