Comorbidity and prognostic indices do not improve the 5-year mortality prediction of components of comprehensive geriatric assessment in hospitalized older patients

BACKGROUND Advancing age is associated with increased vulnerability to chronic health problems. Identifying factors that predict oldest-old status is vital for developing effective clinical interventions and public health strategies. METHODS Observational prospective study of patients aged 75 years and older consecutively admitted to an Acute Geriatric Ward of a tertiary hospital. After a comprehensive geriatric assessment all patients were assessed for five comorbidity indices and two prognostic models. Univariate and multivariate logistic regression models were fitted to assess the association between each score and 5-year mortality. The ability of each score to predict mortality was assessed using the area under the receiver operating characteristic curve. RESULTS 122 patients were enrolled. All patients were followed up for five years. 90 (74%) of them died during the study period. In the logistic regression analyses, apart from age, cognitive impairment and Barthel Index, three indices were identified as statistically associated with 5-year mortality: the Geriatric Index of Comorbidity and the two prognostic indices. The multivariate model that combined age, sex, cognitive impairment and Barthel showed a good discriminate ability (AUC = 0.79), and it did not improve substantially after adding individually any of the indices. CONCLUSIONS Some prognostic models and the Geriatric Index of Comorbidity are better than other widely used indices such as the Charlson Index in predicting 5-year mortality in hospitalized older patients, however, none of these indices is superior to some components of comprehensive geriatric assessment.