[Influence of functional dependence on the case mix in a geriatric unit]

To determine the influence of pre-admission functional status on the case mix in a geriatric unit, after adjustment by the diagnosis-related groups (DRG) patient classification system.

We performed a retrospective observational study in patients admitted to the geriatric unit of a general hospital over a 2-year period. Patients with a length of stay of less than 2 days and transfers from other medical services and hospitals were excluded. The following data were obtained from the minimum data set and from chart review: age, sex, place of residence before admission, Charlson comorbidity index, pre-admission functional status and mobility, cognitive status, length of hospital stay, rate of in-hospital mortality, and the DRG (and DRG weight) for each patient.

A total of 1065 patients were included in this study. The mean age was 84 years (64-102), and 64% were women. Patients with lower functional status were more often female (67.1 vs 55.8%; P< .01), more frequently admitted from nursing homes (35.8 vs 14.7%; P< .01) and had higher mortality (19.3 vs 10.1%; P< .01). These patients also had a higher mean length of stay (12.7 vs 11.9), higher comorbidity scores (P< .01), greater cognitive impairment (P< .01) and higher DRG weight (P=.03). Once the more frequent DRG were reviewed, patients who were dependent had a greater number of respiratory infections and renal problems and had fewer cerebrovascular diseases.

Some clinical characteristics differ in patients with functional dependence. This finding could influence the clinical management of medical services that treat more dependent patients.