Beta-trace protein is not superior to cystatin C for the estimation of GFR in patients receiving corticosteroids.
OBJECTIVE
Comparison of the effect of corticosteroid therapy on the diagnostic performance of cystatin C (Cys) and beta-trace protein (bTP), two endogenous markers of GFR.


METHODS
Out of a total of 193 pediatric inulin clearance studies, a random sample of 85 steroid-free studies served to establish GFR prediction equations (eGFR), which were used to compare the remaining 76 steroid-free and 32 steroid-positive studies (median prednisone dose 33.0 mg m(-2) day(-1)).


RESULTS
We found a positive relationship between prednisone dose and eGFR(betaTP) (b=0.414, p=0.0002) and a negative relationship with eGFR(cys) (b=-0.208, p=0.0091). Only Cys independently predicted GFR below 90 mL min(-1) 1.73 m(-2), both in steroid-positives (b=6.260, p=0.010) and steroid-negatives (b=6.845, p=0.012). Glucocorticoid therapy did not affect the accuracy in estimating GFR within 30% of measured GFR for Cys, while accuracy was lower with bTP (65.6% vs. 81.6%, p=0.08).


CONCLUSIONS
Glucocorticoids have less impact on the diagnostic accuracy of Cys than bTP.
Abbink
Floor C H
FC
Department of Pediatrics, Vrije Universiteit Medical Center, De Boelelaan 1117, NL-1081 HV, Amsterdam, The Netherlands.
Laarman
Céleste A R C
CA
Braam
Katja I
KI
van Wijk
Joanna A E
JA
Kors
Wijnanda A
WA
Bouman
Anna A
AA
Spreeuwenberg
Marieke D
MD
Stoffel-Wagner
Birgit
B
Bökenkamp
Arend
A
D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000494:pharmacology / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D055316:Cystatin C; D015891:Cystatins / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects*; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D007328:Insulin / Q000008:administration & dosage / Q000493:pharmacokinetics; D019746:Intramolecular Oxidoreductases / Q000097:blood*; D007677:Kidney Function Tests; D054834:Lipocalins / Q000097:blood*; D008297:Male; D008657:Metabolic Clearance Rate / Q000187:drug effects; D011241:Prednisone / Q000494:pharmacology / Q000627:therapeutic use
D000305:Adrenal Cortex Hormones; C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D007004:Hypoglycemic Agents; D007328:Insulin; D054834:Lipocalins; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase; D011241:Prednisone