Methods to estimate baseline creatinine and define acute kidney injury in lean Ugandan children with severe malaria: a prospective cohort study

Table 3 Estimates of bSCr and eGFR in healthy community children based on age at enrollment

	Age < 1 years (n = 18)		Age 1 to < 2 years (n = 46)		Age 2 to < 5 years (n = 192)		Age ≥ 5 years (n = 33)		P value¹
	bSCr	eGFR	bSCr	eGFR	bSCr	eGFR	bSCr	eGFR	SCr	eGFR
Reference
Measured SCr	0.23 (0.04)	127.3 (20.8)	0.25 (0.06)	135.9 (29.0)	0.29 (0.07)	138.2 (30.8)	0.37 (0.08)	136.0 (28.7)	< 0.001	0.484
SCr estimated by back calculating from an assumed GFR
bSCr_{GFRSchwartz120}^a	0.24 (0.01)	120 (0.0)	0.27 (0.01)	120 (0.0)	0.32 (0.03)	120 (0.0)	0.41 (0.04)	120 (0.0)	< 0.001	–
bSCr_GFRPottel120^b	0.23 (0.003)	126.8 (4.6)	0.25 (0.01)	131.9 (5.0)	0.29 (0.02)	132.7 (7.0)	0.39 (0.05)	126.8 (8.0)	< 0.001	< 0.001
bSCr_{GFRSchwartz137}^a	0.21 (0.009)	137 (0.0)	0.24 (0.01)	137 (0.0)	0.28 (0.02)	137 (0.0)	0.36 (0.03)	137 (0.0)	< 0.001	< 0.001
SCr estimated directly
bSCr_upperlimit^c	0.39 (0.0)	73.3 (3.1)	0.35 (0.0)	92.9 (4.5)	0.39 (0.03)	97.5 (6.8)	0.54 (0.07)	90.8 (7.1)	< 0.001	< 0.001
bSCr_CCheight^d	0.23 (0.01)	125.9 (0.8)	0.25 (0.01)	128.4 (0.9)	0.29 (0.02)	131.0 (1.4)	0.36 (0.03)	134.7 (1.2)	< 0.001	< 0.001
bSCr_CCage^e	0.23 (0.003)	121.8 (4.5)	0.25 (0.01)	128.8 (5.0)	0.29 (0.02)	132.5 (7.2)	0.37 (0.04)	131.6 (7.2)	< 0.001	< 0.001

¹P value calculated using ANOVA to evaluate mean differences across age categories
^aBedside Schwartz equation (eGFR = 0.413*height/SCr) used to back calculate creatinine assuming a normal of 120 mL/min/1.73m² or 137 mL/min/1.73m² (mean of the community children)
^bPottel equation (eGFR = 107.3/(SCr/Q), where Q = 0.0270*age + 0.2329) used to back calculate creatinine assuming a normal of 120 mL/min per 1.73m²
^cUpper limit using Ceriotti et al., Clin Chem 2008 54:3
^dLinear regression model of height vs. creatinine using healthy community children to estimate baseline creatinine from model
^eLinear regression model of age vs. creatinine using healthy community children to estimate baseline creatinine from model

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