The effect of frailty on hospitalisation trajectories in adults aged 65 and older across 10 European countries: a 14-year longitudinal analysis from the Survey of Health, Ageing, and Retirement in Europe (SHARE)

Evidence indicates an association between frailty and hospitalisation. However, hospital admissions occur repeatedly over time in old age, and most research has only focussed on single hospital admission. This study examines how frailty influences subsequent hospital use-both the risk of hospital admission and the duration of overnight stays-among community-dwelling adults aged 65 years and older across ten European countries over a 14-year period. Seven waves of data from the Survey of Health, Ageing and Retirement in Europe (SHARE) were used. Frailty was measured at baseline (wave 1) using the sex-specific SHARE Frailty Instrument, classifying participants as robust, prefrail, or frail. Hospital admission and length of stay during the past 12 months were measured at waves 2, 4, 5, 6, 7, and 8. Logistic mixed models was fitted to estimate the risk of hospital admission, and negative binomial mixed models to calculate the duration of hospital stays. Baseline frailty was associated with an increased risk of hospital admission over 14 years, yet among those who were hospitalised, frailty was not strongly related to longer stays. These findings suggest that frailty predicts whether older adults are admitted to hospital but is less informative regarding how long they remain once hospitalised. Routine frailty screening in primary care may help identify those at greatest risk and enable better-targeted community interventions to prevent avoidable hospitalisations and improve health outcomes for older people.