Determinants of eGFR at start of renal replacement therapy in paediatric patients

Background. Few studies have investigated the determinants of glomerular filtration rate (GFR) in paediatric patients starting on dialysis or with a transplant.Methods. Data were collected as part of the European Society of Paediatric Nephrology/European Renal Association-European Dialysis and Transplant Association registry from 14 European countries and referred to incident paediatric patients starting on renal replacement therapy (RRT) between 2002 and 2007 under the age of 18 years. Estimated glomerular filtration rate (eGFR) was calculated using the Schwartz formula. Data were adjusted for age, gender, treatment modality at start, primary cause of renal failure (PRD) and regions in Europe (eGFRadj). Results. Median eGFR in the 938 patients starting RRT was 10.4 mL/min/1.73 m² (5th and 95th percentile: 4.0-26.9). Twenty-six patients (2.8%), mainly infants with Finnish-type nephropathy, started with eGFR levels >50 mL/min/1.73 m². Younger age, female gender, starting on dialysis and having a short time between the first visit to a paediatric nephrologist (PN) and start of RRT were associated with lower eGFR at start of RRT. Gender differences were only present during adolescent age and disappeared when using the same K value for both genders. The various PRDs showed large differences in the rate of decline in eGFR between the first visit to a PN and start of RRT; however, this did not result in differences in eGFRadj at start of RRT. Conclusions. The main determinants of eGFR at start of RRT were age, gender, treatment modality at start, and the time between the first visit to a PN and start of RRT. Research is needed to determine the consequences of these differences.