Cognitive frailty predicting death and disability in Chinese elderly

Cognitive frailty (CF) is associated with adverse health outcomes, but different CF models have been proposed in the literature. We explored whether cognitive impairment (CoI) assessed by the Revised Hasegawa dementia scale (HDS-R) and physical frailty (PF) assessed by the modified Frailty Phenotype can be combined to predict risks of adverse outcomes in elderly Chinese subjects.

The data collected in the Rugao Longevity and Aging Study were used. PF was assessed by the modified Frailty phenotype. CoI was defined as the lowest 20% of the HDS-R score. CF was defined as the co-existence of physical frailty and CoI, excluding those with severe CoI(HDR-S ≤ 10). The date and cause of death were acquired from the Death registry of Rugao's Civil Affairs Bureau. Disability was measured using the activities of daily living (ADL) scale.

The prevalence of CF was 2.9% at baseline. During 3-year follow-up, 130 (8.1%) of the 1607 elderly subjects died. The highest mortality risk was observed among subjects with CF (hazard ratio [HR] = 2.94, 95% confidence interval [CI] = 1.28-6.78). Fully adjusted survival plots showed that CF was associated with the highest risk for 3-year mortality. The incidence of ADL disability was 6.0% after 3 years. Compared with the robust and non-CoI elderly, CF was associated with a 10.48-fold (95% CI 2.98-36.80) higher risk of ADL disability.

The CF model defined as a combination of HDS-R and Frail Phenotypes showed predictive validity for all-cause death and new-onset ADL disability 3 years later.