A Comparison of GFR Calculated by Cockcroft-Gault vs. MDRD Formula in the Prognostic Assessment of Patients with Acute Pulmonary Embolism

Abstract

Introduction. Risk stratification is mandatory for optimal management of patients with acute pulmonary embolism (APE). Previous studies indicated that renal dysfunction predicts outcome and can improve risk assessment in APE. Aim. The aim of the study was a comparison of estimated glomerular filtration rate (eGFR) formulas, MDRD, and Cockcroft-Gault (CG), in the prognostic assessment of patients with APE. Materials and Methods. Data from 2274 (1147 M/1127 F, median 71 years) hospitalised patients with APE prospectively included in a multicenter, observational, cohort study were analysed. A serum creatinine measurement as a routine laboratory parameter at the cooperating centers and eGFR calculation were performed on admission. Patients were followed for 180 days. The primary outcome was death from any cause within 30 days. Results. The eGFR levels assessed by both, MDRD (eGFRMDRD) and CG formula (eGFRCG), were highest in patients with low-risk APE and lowest in high-risk APE. The eGFR (using both methods) was significantly lower in nonsurvivors compared to survivors. Using a threshold of <60 ml/min/1.73 m2, eGFRMDRD revealed the primary outcome with sensitivity 67%, specificity 52%, PPV 8%, and NPV 97%, while eGFRCG had a sensitivity 62%, specificity 62%, PPV 8.6%, and NPV 96%. The area under the ROC curve for eGFRCG tended to be higher than that for eGFRMDRD: 0.658 (95% CI: 0.608-0.709) vs. 0.631 (95% CI: 0.578-0.683), $p=0.12$ . A subanalysis of ROC curves in a population above 65 yrs showed a higher AUC for eGFRCG than based on MDRD. Kaplan-Meier analysis showed a worse long-term outcome in patients with impaired renal function. Conclusion. eGFRMDRD and eGFRCG assessed on admission significant short- and long-term mortality predictors in patients with APE. The eGFRCG seems to be a slightly better 30-day mortality predictor than eGFRMDRD in the elderly.