Tamara van Donge

Dynamics of creatinine in ELBW neonates 135 7 Table 3: Evaluation methods to assess the predictive performance of the developed creatinine model. Evaluation methods Value [95% CI] Units Mean prediction error (MPE) -0.0028 [-0.0075 - 0.0019] mg/dl Relative MPE (RMPE) 0.855 [0.139 - 1.572] % Mean squared error (MSE) 0.0069 [0.0061 - 0.0077] mg/dl Relative root mean square error (RMSE) 12.755 [12.108 - 13.371] % Development of Scr reference ranges: model-based simulations Reference ranges for Scr concentrations and creatinine clearance are shown in Figure 3 and Table 4. Scr concentrations and creatinine clearance values for typical ELBW neonates (no IIV), stratified for three reference GA values, namely 24, 27 and 32 weeks are illustrated in Figure S1, S2 (Supporting Information 3). BSA-transformed creatinine clearances (in ml/min/1.73m 2 ) are presented in Supporting Information 4. The ratio of the amount of creatinine produced versus eliminated for typical ELBW neonates, stratified per GA is illustrated in Figure S3 (Supporting Information 3). 24 weeks GA 0.25 0.50 0.75 1.00 1.25 1.50 Scr concentration (mg/dl) 24 weeks GA 1 7 14 21 28 35 42 0.25 0.50 0.75 Time after birth (days) Creatinine clearance (ml/min) 27 weeks GA 0.25 0.50 0.75 1.00 1.25 1.50 27 weeks GA 1 7 14 21 28 35 42 0.25 0.50 0.75 Time after birth (days) 32 weeks GA 0.25 0.50 0.75 1.00 1.25 1.50 32 weeks GA 1 7 14 21 28 35 42 0.25 0.50 0.75 Time after birth (days) Figure 3: Simulated serum creatinine (Scr) concentration and clearance values for ELBW neonates with inter-individual variability (IIV) and 95% prediction intervals. Upper panel: Scr concentrations for ELBW neonates born at 24, 27 and 32 weeks of gestation. Lower panel: creatinine clearance for ELBW neonates born at 24, 27 and 32 weeks of gestation.