Chronic Kidney Disease Epidemiology Collaboration Equation Accuracy in Predicting Peritoneal Dialysis-Delivered Creatinine Clearance

Introduction: Measuring total (residual kidney plus peritoneal) creatinine clearance (CrCl) with 24-h urine and dialysate collections is recommended for peritoneal dialysis (PD) adequacy evaluation. Prediction equations applied in this instance could simplify the approach. Cockcroft-Gault and modification of diet in renal disease (MDRD) four (MDRD-4) and six (MDRD-6) variables equations have been tested in this setting, and conflicting results have been reported. The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation is currently considered to be more sensitive than the established equations for kidney function estimation. However, its performance in PD adequacy evaluation has not been studied. Our aim was to assess CKD-EPI equation's performance in predicting total measured CrCl (MCC) in PD patients. Material and methods: A group of 23 consecutive PD patients, male/female: 5/18, median age: 66 (32-91) years, median time on PD 32 (2-126) months, were enrolled in the study. All were treated by automated PD (APD). Sixteen out of twenty-three had residual renal function (RRF). MCC was determined from 24-h dialysate and urine collections and also predicted by Cockcroft-Gault, MDRD (4 and 6), and CKD-EPI equations. Results: CKD-EPI and MDRD-6 estimation results were similar to MCC (9.01 +/- 3.90 and 9.54 +/- 2.98 vs. 8.64 +/- 3.75 mL/min/1.73 m(2) p = 0.49 and 0.09, respectively). Neither the presence nor the volume of residual urine affected the accuracy of prediction. Cockcroft-Gault and MDRD-4 equations differed significantly from MCC and were not accurately predictive. Conclusion: CKD-EPI equation could be used with accuracy for predicting MCC in PD patients. Only MDRD-6 showed similar accuracy, whereas MDRD-4 and Cockcroft-Gault equations were found to be inappropriate in this setting.