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Utility of Cystatin C-based Equation for the Estimation of Glomerular Filtration Rate in a Pediatric Population
Ridwan B Ibrahim1,2, Poyyapakkam Srivaths3, Estella Tam2
1Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, United States.
Insights
The CKiD U25-CysC equation offers the best estimation of measured glomerular filtration rate (mGFR) in pediatric patients. This study found it outperformed other non-race-corrected equations for assessing kidney function.
Area of Science:
- Pediatric Nephrology
- Renal Function Assessment
- Biomarker Analysis
Background:
- Accurate kidney function assessment is crucial for early detection of kidney damage.
- Estimated glomerular filtration rate (eGFR) equations using cystatin C (CysC) and creatinine are alternatives to measured glomerular filtration rate (mGFR).
- CKiD under 25 (CkiD U25) equations show promise for children and young adults with chronic kidney disease (CKD).
Purpose of the Study:
- To evaluate the performance of CKiD U25 equations for estimating kidney function in pediatric patients.
- To compare CKiD U25 equations with other commonly used non-race-corrected (NRC) eGFR equations in a pediatric cohort.
- To assess the accuracy of different eGFR equations against measured glomerular filtration rate (mGFR).
Main Methods:
- Retrospective comparison of mGFR (using Tc-99mDTPA) with eGFR from various equations.
- Study included 57 patients aged 6 months to 22 years from diverse racial/ethnic backgrounds.
- Ordinary least squares regression analyses were employed to determine correlations between mGFR and eGFR values.
Main Results:
- The average mGFR for the cohort was 84.1 mL/min/1.73 m².
- Non-race-corrected creatinine equations generally overestimated eGFR; CKiD U25-creatinine showed the least bias.
- CKiD U25-CysC and Schwartz CysC equations demonstrated the best correlation with mGFR, highest P30 values, and lowest biases.
Conclusions:
- Both CKiD U25-CysC and Schwartz CysC equations provide good estimations of mGFR in the studied pediatric population.
- The CKiD U25-CysC equation exhibited the best overall performance when compared to mGFR in this cohort.
- These findings support the use of CKiD U25-CysC for improved eGFR assessment in children and young adults.
Background:
The accurate assessment of kidney function is vital for the early detection of kidney damage. The estimated glomerular filtration rate GFR (eGFR) from serum cystatin C (CysC) and creatinine-based equations are commonly used in clinical practice as an alternative to the invasive measured glomerular filtration rate (mGFR), which is the usually accepted overall best index of kidney function in health and disease. Recently the CKiD under 25 (CkiD U25) equations have been shown to perform well in children and young adults with chronic kidney disease (CKD). In this focused report, we evaluated the performance of the CkiD U25 equations alongside 3 non-race-corrected (NRC) eGFR equations commonly used in pediatrics in our cohort.
Methods:
mGFR measured following the intravenous injection of tracer Tc-99mDTPA was retrospectively compared with eGFR from these equations in 57 patients (6 months to 22 years) from different races/ethnicities. Ordinary least squares regression analyses were used to assess correlation between the mGFRs and eGFRs.
Results:
The average mGFR for this cohort was 84.1 mL/min/1.73 m2. The NRC creatinine equations overestimated eGFR across all groups, with the lowest bias for CKiD U25-creatinine (22.59 mL/min/1.73 m2). The best correlations to mGFR, P30, and lowest biases were the CKiD U25-CysC (0.6281, 80.7%, 3.72 mL/min/1.73 m2) and Schwartz CysC (0.6372, 77.2%, -4.68 mL/min/1.73 m2).
Conclusions:
Overall, both CKiD U25-CysC and Schwartz CysC provide a good estimation of mGFR with the CKiD U25-CysC having the overall best performance compared to mGFR in our study.
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