Estimating GFR in Pediatric Transplant Recipients

The Chronic Kidney Disease in Children (CKiD) 2012 formula had the best performance in assessing renal function in pediatric kidney transplant recipients, according to results of a study conducted by Vandrea de Souza, MD, et al.

The most commonly used formulas to predict glomerular filtration rate (GFR) in this population are plasma creatinine (PCr)-based or cystatin C (CystC)-based. However, according to the researchers, those formulas may underperform because corticosteroids and trimethoprim may affect concentration of PCr and prednisone and calcineurin inhibitors may affect concentration of CystC.

In this study examining six formulas in pediatric kidney transplant recipients, the researchers compared the formulas using inulin clearance as reference and assessed performance according to CKD stages in a historical cohort of 73 pediatric transplant recipients. The study assessed the ability of the formulas to identify GFRs <60, ,<75, and <90 mL/min/1.73 m2.

At measured GFR (mGFR) ≥90 mL/min/1.73 m2, the Zappitelli formula had the highest 30% accuracy (P30) and the bedside Schwartz had the highest 10% accuracy (P10). At mGFR ≥60 and <90 mL/min/1.73 m2, all formulas had P30 values >80%. However, only the CKiD 2012 formula had a P10 value >50%. At mGFR <60 mL/min/1.73 m2, the CKiD and Schwartz-Lyon formulas had the highest P10 (45% adn43%) and P30 (90% and 91%).

“In pediatric kidney transplant recipients, the CKiD 2012 formula had the best performance at mGFRs <90 mL/min/1.73 m2. CystC-based formulas were not superior to PCr-based formulas,” the researchers concluded.