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Mean of creatinine clearance and urea clearance examined over 1 h estimates glomerular filtration rate accurately and precisely in children
Author(s) -
Okuda Yusuke,
Hamada Riku,
Uemura Osamu,
Sakai Tomoyuki,
Sawai Toshihiro,
Harada Ryoko,
Hamasaki Yuko,
Ishikura Kenji,
Hataya Hiroshi,
Honda Masataka
Publication year - 2021
Publication title -
nephrology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 61
eISSN - 1440-1797
pISSN - 1320-5358
DOI - 10.1111/nep.13911
Subject(s) - renal function , interquartile range , medicine , confidence interval , urology , cystatin c , creatinine , kidney disease , clearance
Abstract Aim Accurate and precise estimation of glomerular filtration rate (GFR) is essential in kidney disease. We evaluated the usefulness of the mean of creatinine clearance (C Cr ) and urea clearance (C UN ) examined over a 1‐h urine collection period (1‐h (C Cr + C UN )/2) in a retrospective, cross‐sectional study across two centres, as a relatively simple method for estimating GFR in children. Methods Children aged ≤18 years who underwent inulin clearance (C In ) tests were eligible. Two clearance values were obtained during a 2‐h test consisting of two periods of 1 h each. The mean clearance in two periods was defined as 1‐h clearance. 1‐h (C Cr + C UN )/2, 1‐h C Cr , 1‐h C UN and GFR estimated by Cr‐based and cystatin C (CysC)‐based formulas for Japanese children were compared with C In . Bland–Altman plots were used to evaluate correlations. The primary outcome measure was the correlation between 1‐h (C Cr + C UN )/2 and C In . Results Fifty‐three children were analysed. Their median age was 10.9 (interquartile range [IQR] 5.3–14.2) years, and median C In and 1‐h (C Cr + C UN )/2 were 77.0 (IQR: 51.5–95.1) and 81.0 (IQR: 64.1–97.7) ml/min/1.73 m 2 , respectively. Percentage difference of C In and 1‐h (C Cr + C UN )/2 in the Bland–Altman plot was −11.2% (95% confidence interval − 15.3% – −7.1%), with 95% lower and upper limits of agreement of −40.3% and 18.0%, respectively. Thus, 1‐h (C Cr + C UN )/2 was 1.12 times C In . Conclusion 1 h (C Cr + C UN )/2 was almost concordant with C In . 1‐h (C Cr + C UN )/2 can estimate GFR accurately and precisely, making it a simple and speedy test for use in clinical practice.