Prognostic relevance of glomerular filtration rate estimation obtained through different equations in hospitalized elderly patients

The estimated glomerular filtration rate (eGFR) is a predictor of important outcomes and its reduction has been associated with the risk of all-cause mortality in both general population and elderly patients. However while reduced renal function is common in older people, the best method for estimating GFR remains unclear, especially in an acute care setting. Most studies analyzing the accuracy of eGFR in the elderly were carried out in different heterogeneous settings. In this study, we compare the prognostic value of different formulas estimating GFR in predicting the risk of in-hospital morbidity and mortality within 3 months from discharge in elderly hospitalized patients. Data were extracted from "Registro Politerapia Società Italiana di Medicina Interna (REPOSI)". Patients with available creatinine values at hospital admission were selected and eGFR was calculated according to the different formulas: Cockcroft-Gault, Modification of Diet in Renal Disease equation, Chronic Kidney Disease Epidemiology Collaboration, Berlin Initiative Study and Full Age Spectrum. 4621 patients were included in the analysis. Among these, 4.2% and 14.2% died during hospitalization and within 3 months from discharge, respectively. eGFR > 60 ml/min/1.73 m2 at admission was associated with a very low risk of mortality during the hospital stay and within 90 days from discharge, while an eGFR < 60 ml/min/1.73 m2 was associated with unfavorable outcomes, although with a poor level of accuracy (AUC 0.60-0.66). No difference in predictive power between different equations was found. Physicians should be aware of the prognostic role of eGFR in a comprehensive assessment of elderly in-patients.