The risk of adverse outcomes in hospitalized older patients in relation to a frailty index based on a comprehensive geriatric assessment

Background: prognostication for frail older adults is complex, especially when they become seriously ill. Objectives: to test the measurement properties, especially the predictive validity, of a frailty index based on a comprehensive geriatric assessment (FI-CGA) in an acute care setting in relation to the risk of death, length of stay and discharge destination. Design and setting: prospective cohort study. Inpatient medical units in a teaching, acute care hospital. Subjects: individuals on inpatient medical units in a hospital, n = 752, aged 75+ years, were evaluated on their first hospital day; to test reliability, a subsample (n = 231) was seen again on Day 3. Measurements: all frailty data collected routinely as part of a CGA were used to create the FI-CGA. Mortality data were reviewed from hospital records, claims data, Social Security Death Index and interviews with Discharge Managers. Results: thirty-day mortality was 93 (12.4%; 95% confidence interval (CI) = 10-15%) of whom 52 died in hospital. The risk of dying increased with each 0.01 increment in the FI-CGA: hazard ratio (HR) = 1.05, (95% CI = 1.04-1.07). People who were discharged home had the lowest admitting mean FI-CGA = 0.38 (+/- standard deviation 0.11) compared with those who died, FI-CGA = 0.51 (+/- 0.12) or were discharged to nursing home, FI-CGA = 0.49 (+/- 0.11). Likewise, increasing FI-CGA values on admission were significantly associated with a longer length of hospital stay. Conclusions: frailty, measured by the FI-CGA, was independently associated with a higher risk of death and other adverse outcomes in older people admitted to an acute care hospital.