Current equations estimating glomerular filtration rate in primary care: Comparison and determinants

Abstract Objective. The aims of this study were to compare estimated glomerular filtration rate (eGFR) by Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, to assess the classification of chronic kidney disease (CKD) stages by both equations, and to identify factors associated with differences between both equations in patients with or at high risk of CKD managed in primary care. Material and methods. This was an observational study of 803 patients with CKD, long-standing, severe hypertension and diabetes exclusively managed in primary care. Bias and precision between the two equations used to calculate eGFR were quantified as proposed by Bland and Altman. Results. In 1534 eGFR calculations, mean eGFRMDRD was 0.8 ± 3.6 ml/min/1.73 m2 higher than eGFRCKD-EPI. Precision between the two equations was ±7.1 ml/min/1.73 m2. Classification of CKD stages by MDRD or CKD-EPI equations agreed in 93.3% of cases. Age above 70 years, eGFR below 60 an...