The Severity of Acute Illness and Functional Trajectories in Hospitalized Older Medical Patients.

BACKGROUND: Acute diseases and hospitalization are associated with functional deterioration in older persons. Although most of the functional decline occurs before hospitalization in response to the acute diseases, the role played by comorbidity in the functional trajectories around hospitalization is unclear.

METHODS: Observational prospective study of 696 elderly individuals hospitalized in two Italian general medicine wards. Functional status of the elderly patients at 2 weeks before hospitalization (baseline), at hospital admission, and at discharge was measured by the Barthel Index. Comorbidity was measured at admission by the Geriatric Index of Comorbidity (GIC), a tool mostly based on illness severity. The association of GIC with changes in functional status before hospitalization (between baseline and admission), during hospitalization (between admission and discharge), and in the overall period between baseline and discharge was assessed by logistic regression analyses. Hospitalization-associated disability (HAD) was defined as a functional decline between baseline and discharge.

RESULTS: Illness severity (GIC 3-4 vs 1-2: odds ratio [OR] 2.2, 95% CI [confidence interval] 1.5-3.3, p < .0001) and older age significantly predicted prehospital functional decline (between baseline and admission). Illness severity (OR 1.9, 95% CI 1.2-3, p = .004) and older age were also predictive of HAD, even after adjustment for each coded primary discharge diagnosis. After adjustment for the occurrence of prehospital functional decline, however, illness severity and older age were not predictive of HAD anymore.

CONCLUSIONS: The severity of illnesses was strongly associated with adverse functional outcomes around hospitalization, but frailty, intended as functional vulnerability to the acute disease before hospitalization, was a stronger predictor of HAD than illness severity and age.