Predicting functional status outcomes in hospitalized patients aged 80 years and older

OBJECTIVE: To develop a model estimating the probability of a patient aged 80 years or older having functional limitations 2 months and 12 months afte r being hospitalized. DESIGN: A prospective cohort study. SETTING: Four teaching hospitals in the US. PARTICIPANTS: Enrolled patients were nonelective hospital admissions aged 8 0 years or older who stayed in hospital at least 48 hours. The 804 patients who survived and completed an interview at 2 months and the 450 who comple ted an interview at 12 months were from the 1266 patients in the Hospitaliz ed Elderly Longitudinal Project (HELP) (76% and 47% of survivors, respectiv ely). Median age of the 2-month survivors was 84.7 years. MEASUREMENTS AND MAIN OUTCOMES: Patient function 2 and 12 months after enro llment was defined by the number of dependencies in Activities of Daily Liv ing (ADLs). Ordinal logistic regression models were constructed to predict functional status. Predictors included demographic characteristics, disease category, geriatric conditions, severity of physiologic imbalance, current quality of life, and exercise capacity and ADLs 2 weeks before study admis sion. RESULTS: Before admission, 39 % of patients were functionally independent i n ADLs. Of patients who survived and were interviewed at 2 months, 32% were functionally independent, and at 12 months, 36% were independent. Among pa tients with no baseline dependencies, 42% had developed one or more limitat ions 2 months later, and 41% had limitations 12 months later. The patient's ability to perform activities of daily living at baseline was the most imp ortant predictor of functional status at both 2 and 12 months. In a multiva riable predictive model, independent predictors of poorer functional status at 2 months included: worse baseline functional status and quality of life ; depth of coma, if any; lower serum albumin level; presence of dementia, d epression, or incontinence; being bedridden; medical record documentation o f need for nursing home; and older age. Model performance, assessed using S omers' D, was 0.61 for 2 months and 0.57 for 12 months (Receiver Operating Characteristic (ROC) area = 0.81 and .79, respectively.) Bootstrap validati on of the month 2 model also yielded a Somers' D = 0.60. The models were we ll calibrated over the entire risk range. The ROC area for prediction of th e loss of independence was 0.76 for 2 months and 0.68 for 12 months. CONCLUSIONS: Many older patients are functionally impaired at the time of h ospitalization, and many develop new functional limitations. A limited amou nt of readily available clinical information can yield satisfactory predict ions of functional status 2 months after hospitalization. Models like this may prove to be useful in clinical care. This work illuminates a potential method for risk adjustment in research studies and for monitoring quality o f care.