Table 5.

Estimating formulas for longitudinal prediction of visit 2 GFR using the visit 2 cross-sectional measures and change of biomarker values from the two visits $eGF{R}_2=a{\left[\left(ht/SC{r}_2\right)\right]}^b{\left[\left(30/BU{N}_2\right)\right]}^c{\left[\frac{ht/SC{r}_2}{ht/SC{r}_1}\right]}^d$

Model	a	b	c	d	R2 (%)	% within 30%	% within 10%	$\sqrt{\text{MSE}}$a
None	40.78 ± 1.14	0	0	0	–	48	17	0.414
V	41.91 ± 0.58	0.671 ± 0.042	0.169 ± 0.041	0	76	82	35	0.204
VI	41.75 ± 0.58	0.732 ± 0.048	0.170 ± 0.041	−0.188 ± 0.075	77	81	36	0.202

Parameters were estimated in a training set of 220 children.

^aOf the log transformed iGFR₂