Frailty, cognitive impairment and mortality among the oldest old.

INTRODUCTION: Both frailty and cognitive impairment are increasingly prevalent with advancing age. Nonetheless among the oldest old their relationship is poorly described. This study examines the association between frailty status and cognitive impairment at age 85 and their impact on 5-year mortality.

METHODS: A representative sample of 840 community dwelling people from the Jerusalem Longitudinal Cohort Study was comprehensively assessed at age 85. Frailty was defined according to the "phenotype of frailty", as including at least three of the following: weight loss, slowness, weakness, exhaustion and low physical activity levels. Pre frailty was defined as 1-2/5 criteria. Cognitive impairment was assessed according to the Mini Mental State Examination (MMSE). Mortality data was collected from age 85-90.

RESULTS: A total of 164 (19.5%) were frail, 470 (56%) were pre frail and 206 (24.5%) were not frail, with prevalence of MMSE≤24 being 53.3%, 15%, and 7.4% respectively. A uniform pattern of increased adverse health, affective, disease and functional measures were associated with frailty status. Frailty status was significantly associated with cognitive impairment, with an Odds Ratios of 3.77 (95%CI 1.42-9.99) for MMSE≤24 after adjustment for socio demographic, medical mood and functional covariates. Among frail, pre frail and non frail subjects, 5-year mortality was 44.5%, 20.4%, 13.6% respectively. Mortality among frail subjects with or without cognitive impairment was 54.2% vs. 54.9%, p=0.9). Adjusting together for frailty, MMSE, education and gender, the Hazards ratio for 5-year mortality for frailty was 3.861 (95%CI 2.4-6.2), and for MMSE≤24 was 1.25 (95%CI 0.87-1.78).

CONCLUSIONS: Among the oldest old, frailty status was significantly associated with cognitive impairment; after adjustment, frailty alone was predictive of subsequent mortality.