Can augmented renal clearance be detected using estimators of glomerular filtration rate?

Table 1 Agreement analysis between CrCl_24h and formulae estimating renal function

	All ICU days (n = 51,604)	CrCl_24h < 130 ml/min/1.73 m² (n = 41,290)	CrCl_24h ≥ 130 ml/min/1.73 m² (n = 10,314)
Median (IQR) (ml/min/1.73 m²)
CrCl24h	73 (37;118)	58 (30;88)	166 (145;200)
CrCl_CG	83 (50;127)	70 (43;103)	145 (116;183)
eGFR_MDRD	87 (50;130)	72 (42;109)	143 (115;185)
eGFR_CKD-EPI	88 (51;108)	75 (43;99)	116 (104;130)
Correlation with CrCl_24h = Spearman correlation coefficient
CrCl_CG	0.63°	0.62°	0.18°
eGFR_MDRD,	0.59°	0.60°	0.15°
eGFR_CKD-EPI	0.69°	0.72°	0.19°
Mean bias (95% CI) = mean difference CrCl_24h – estimator (ml/min/1.73 m²)
CrCl_CG	− 11 (− 11;-10)	− 20 (− 20;-19)	25 (23;27)
eGFR_MDRD	− 14 (− 15;− 14)	− 23 (− 23;− 23)	21 (19;23)
eGFR_CKD-EPI	3 (3;4)	− 12 (− 13;− 12)	66 (64;67)
Precision = SD of the bias (ml/min/1.73 m²)
CrCl_CG	55	41	83
eGFR_MDRD	61	46	94
eGFR_CKD-EPI	48*	26*	62*
Accuracy = percentage within 30% of CrCl_24h
CrCl_CG	47	45	58
eGFR_MDRD	45	43	56
eGFR_CKD-EPI	50	51	45

n number of ICU days; CrCl_24h creatinine clearance measured by 24-h urine collection, corrected for body surface area; IQR interquartile range; CrCl_CG estimated creatinine clearance by the Cockcroft – Gault formula, corrected for body surface area; eGFR_MDRD estimated glomerular filtration rate by the 4-variable Modification of Diet in Renal Disease formula; eGFR_CKD-EPI estimated glomerular filtration rate by the Chronic Kidney Disease Epidemiology Collaboration formula; SD standard deviation; CI confidence interval
°p < 0,001
*Best performing

ISSN: 1364-8535