Improved equations estimating GFR in children with chronic kidney disease using an immunonephelometric determination of cystatin C.

Abstract

The Chronic Kidney Disease in Children study is a cohort of about 600 children with chronic kidney disease (CKD) in the United States and Canada. The independent variable for our observations was a measurement of glomerular filtration rate(GFR) by iohexol disappearance (iGFR) at the first two visits 1 year apart and during alternate years thereafter. In a previous report, we had developed GFR estimating equations utilizing serum creatinine, blood urea nitrogen, height, gender, and cystatin C measured by an immunoturbidimetric method; however, the correlation coefficient of cystatin C and GFR(0.69) was less robust than expected. Therefore, 495 samples were re-assayed using immunonephelometry. The reciprocal of immunonephelometric cystatin C was as well correlated with iGFR as was height/serum creatinine (both 0.88). We developed a new GFR estimating equation using a random 2/3 of 965 person-visits and applied it to the remaining 1/3 as a validation data set. In the validation dataset, the correlation of the estimated GFR with iGFR was 0.92 with high precision and no bias; 91 and 45% of eGFR values were within 30 and 10% of iGFR, respectively. This equation works well in children with CKD in a range of GFR from 15 to 75 ml/min per 1.73 m2. Further studies are needed to establish the applicability to children of normal stature and muscle mass, and higher GFR.

• Authors: George J Schwartz, Michael F Schneider, Paula S Maier, Marva Moxey-Mims, Vikas R Dharnidharka, Bradley A Warady, Susan L Furth, Alvaro Muñoz
• Journal: Kidney international (Kidney Int) Vol. 82 Issue 4 Pg. 445-53 (Aug 2012) ISSN: 1523-1755 [Electronic] United States
• PMID: 22622496 (Publication Type: Journal Article, Multicenter Study, Research Support, N.I.H., Extramural, Validation Study)

Chemical References

• Biomarkers
• CST3 protein, human
• Contrast Media
• Cystatin C
• Iohexol
• Creatinine

Topics

• Adolescent
• Biomarkers (blood)
• Blood Urea Nitrogen
• Body Height
• Canada
• Child
• Child, Preschool
• Cohort Studies
• Contrast Media
• Creatinine (blood)
• Cystatin C (blood)
• Female
• Glomerular Filtration Rate
• Humans
• Immunoassay
• Infant
• Iohexol
• Kidney (metabolism, physiopathology)
• Linear Models
• Male
• Models, Biological
• Multivariate Analysis
• Nephelometry and Turbidimetry
• Predictive Value of Tests
• Renal Insufficiency, Chronic (blood, diagnosis, physiopathology)
• Reproducibility of Results
• Time Factors
• United States