title: Applicability of estimating glomerular filtration rate equations in pediatric patients: comparison with a measured glomerular filtration rate by iohexol clearance.
abstract: Estimating glomerular filtration rate (eGFR) has become popular in clinical medicine as an alternative to measured GFR (mGFR), but there are few studies comparing them in clinical practice. We determined mGFR by iohexol clearance in 81 consecutive children in routine practice and calculated eGFR from 14 standard equations using serum creatinine, cystatin C, and urea nitrogen that were collected at the time of the mGFR procedure. Nonparametric Wilcoxon test, Spearman correlation, Bland-Altman analysis, bias (median difference), and accuracy (P15, P30) were used to compare mGFR with eGFR. For the entire study group, the mGFR was 77.9 ± 38.8 mL/min/1.73 m(2). Eight of the 14 estimating equations demonstrated values without a significant difference from the mGFR value and demonstrated a lower bias in Bland-Altman analysis. Three of these 8 equations based on a combination of creatinine and cystatin C (Schwartz et al. New equations to estimate GFR in children with CKD. J Am Soc Nephrol 2009;20:629-37; Schwartz et al. Improved equations estimating GFR in children with chronic kidney disease using an immunonephelometric determination of cystatin C. Kidney Int 2012;82:445-53; Chehade et al. New combined serum creatinine and cystatin C quadratic formula for GFR assessment in children. Clin J Am Soc Nephrol 2014;9:54-63) had the highest accuracy with approximately 60% of P15 and 80% of P30. In 10 patients with a single kidney, 7 with kidney transplant, and 11 additional children with short stature, values of the 3 equations had low bias and no significant difference when compared with mGFR. In conclusion, the 3 equations that used cystatin C, creatinine, and growth parameters performed in a superior manner over univariate equations based on either creatinine or cystatin C and also had good applicability in specific pediatric patients with single kidneys, those with a kidney transplant, and short stature. Thus, we suggest that eGFR calculations in pediatric clinical practice use only a multivariate equation.
authors.affiliation: Division of Kidney Diseases, Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Ill; Division of Kidney Diseases, Department of Pediatrics, Ann and Robert H Lurie Children's Hospital of Chicago, Chicago, Ill; Department of Pediatrics, First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Deng
authors.affiliation: Division of Kidney Diseases, Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Ill; Division of Kidney Diseases, Department of Pediatrics, Ann and Robert H Lurie Children's Hospital of Chicago, Chicago, Ill.
authors.forename: Gal
authors.initials: G
authors.lastname: Finer
authors.affiliation: Department of Pathology and Laboratory Medicine, Ann and Robert H Lurie Children's Hospital of Chicago, Chicago, Ill; Department of Pathology and Laboratory Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Ill.
authors.forename: Shannon
authors.initials: S
authors.lastname: Haymond
authors.affiliation: Division of Kidney Diseases, Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Ill; Division of Kidney Diseases, Department of Pediatrics, Ann and Robert H Lurie Children's Hospital of Chicago, Chicago, Ill.
authors.forename: Ellen
authors.initials: E
authors.lastname: Brooks
authors.affiliation: Division of Kidney Diseases, Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Ill; Division of Kidney Diseases, Department of Pediatrics, Ann and Robert H Lurie Children's Hospital of Chicago, Chicago, Ill. Electronic address: c-langman@northwestern.edu.
authors.forename: Craig B
authors.initials: CB
authors.lastname: Langman
mesh_terms: D000293:Adolescent; D001827:Body Height; D002648:Child; D002675:Child, Preschool; D003710:Demography; D005919:Glomerular Filtration Rate; D006801:Humans; D007223:Infant; D007472:Iohexol / Q000493:pharmacokinetics*; D007668:Kidney / Q000002:abnormalities / Q000503:physiopathology; D016030:Kidney Transplantation; D015999:Multivariate Analysis; D012044:Regression Analysis; D055815:Young Adult
chemical_list: D007472:Iohexol