Factors related to length of stay in a geriatric evaluation and rehabilitation unit.

Factors related to length of stay were examined in 295 elderly patients (mean age = 79.0 +/- 7.3, range 65-94; males = 75, females = 220), consecutively admitted to a Geriatric Evaluation and Rehabilitation Unit (GERU, P. Richiedei Hospital, Gussago, Brescia, Italy) over a twelve-month period (November 1, 1993-October 31, 1994). Mini Mental State Examination (MMSE), Geriatric Depression Scale (GDS), Basic Activities of Daily Living (BADL), Instrumental Activities of Daily Living (IADL), Tinetti Scale, Prognostic Nutritional Index (PNI), number of diseases and number of administered drugs were evaluated. An index of Disease Severity (IDS) was utilized to estimate the level of comorbidity severity. Three comorbidity classes were thus defined: I) patients with no disease of relevant severity; II) patients with only one disease of relevant severity accompanied by clinically significant comorbidity; and III) patients with two or more relevant diseases. The variables associated with the length of stay proved to be classes of comorbidity, MMSE, dependence in BADL and IADL, Tinetti scale, and PNI. The association of longer length of stay with greater comorbidity was enhanced by impairment in gait and balance (Tinetti < 18) and malnutrition (PNI > 45). These data suggest that the length of stay in hospital is related to comorbidity in patients with conditions of physical and biomedical frailty.