The relationship between intervening hospitalizations and transitions between frailty states.

BACKGROUND: Frailty among older persons is a dynamic process, characterized by frequent transitions between frailty states over time. We performed a prospective longitudinal study to evaluate the relationship between intervening hospitalizations and these transitions.

METHODS: We studied 754 nondisabled community-living persons, aged 70 years or older. Frailty, assessed every 18 months for 108 months, was defined on the basis of muscle weakness, exhaustion, low physical activity, shrinking, and slow walking speed. Participants were classified as frail if they met three or more of these criteria, prefrail if they met one or two of the criteria, or nonfrail if they met none of the criteria. Hospitalizations were ascertained every month for a median of 108 months.

RESULTS: The exposure rates (95% confidence interval) of hospitalization per 1,000 months, based on frailty status at the start of each 18-month interval, were 19.7 (16.2-24.0) nonfrail, 32.9 (29.8-36.2) prefrail, and 57.2 (52.9-63.1) frail. The likelihood of transitioning from states of greater frailty to lesser frailty (ie, recovering) was consistently lower based on exposure to intervening hospitalizations, with adjusted hazard ratios per each hospitalization ranging from 0.46 (95% confidence interval: 0.21-1.03) for the transition from frail to nonfrail states to 0.52 (95% confidence interval: 0.42-0.65) for the transition from prefrail to nonfrail states. Hospitalization had more modest and less consistent effects on transitions from states of lesser frailty to greater frailty. Nonetheless, transitions from nonfrail to frail states were uncommon in the absence of a hospitalization.

CONCLUSIONS: Recovery from prefrail and frail states is substantially diminished by intervening hospitalizations. These results provide additional evidence highlighting the adverse consequences of hospitalization in older persons.