An index of Brazilian frailty and its association with social factors.

Background: The Brazilian population is aging rapidly and it is necessary to establish tools to map the elderly population regarding its frailty, which is a common adverse condition during the aging process. The National Health Survey (PNS in Portuguese) data makes it possible.

Objective: This study aimed to construct a frailty index (FI) of the elderly Brazilian population using the PNS data, in order to compare it with the index of other population and to measure its association with social factors.

Method: A set of the PNS variables was selected to carry out the index, taking into account criteria identified in the literature. The FI score was categorized as: non-frail (FI ≥ 0.10); vulnerable (0.10 < FI ≥ 0.21); frail (0.21 < FI ≥ 0.45); and most frail (FI > 0.45). A logistic regression model was adjusted to measure the association of the FI with some risk factors and social factors.

Results: The Brazilian FI, calculated with 26 variables, presented a mean score of 0.13 and the best was a gamma distribution. Of the individuals, 53.9% were non-frail, 30.1% vulnerable, 13.6% frail and 2.5% most frail. The variables that significantly distinguished each level of the frailty were: self-perceived health status; instrumental activities of daily living (IADL); and difficulty in hearing, seeing and concentrating. Additionally, socio-demographic and sedentary lifestyle were identified as risk factors.

Conclusion: The proposed index showed a similar distribution to the ones observed in the literature and it is associated with social factors. These findings are useful to guide the planning of the Brazilian health policy for the elderly population.