Intra-individual variation of cystatin C and creatinine in pediatric solid organ transplant recipients

Area of Science:

• Pediatric Nephrology
• Transplantation Medicine
• Biomarker Analysis

Background:

• Glomerular filtration rate (GFR) monitoring is crucial post-solid organ transplant (Tx).
• Controversy exists regarding the reliability of cystatin C (CysC) versus serum creatinine (SCr) for GFR assessment in transplant recipients.
• Pediatric transplant patients require accurate and consistent GFR evaluation.

Purpose of the Study:

• To compare the intra-patient variability of CysC and SCr in children following solid organ transplantation.
• To evaluate the feasibility of CysC as a GFR marker in this population.
• To assess GFR estimation formulas based on CysC against the established Schwartz formula.

Main Methods:

• Analysis of 178 simultaneous SCr and CysC measurements from 20 pediatric solid organ transplant recipients.
• Calculation of intra-individual coefficient of variation (CV) for SCr and CysC.
• Comparison of GFR estimated by the Schwartz formula and a CysC-based formula.

Main Results:

• Mean CV for SCr was 7.71% and for CysC was 10.27% (p=0.04), with no significant difference when excluding patients with bladder augmentation.
• CV for GFR estimated by the Schwartz formula (7.44%) was significantly lower than GFR calculated from CysC (12.52%, p=0.001).
• CysC and CysC-calculated GFR demonstrated equivalent, but not superior, performance compared to SCr and the Schwartz formula for longitudinal follow-up.

Conclusions:

• Cystatin C can be utilized for longitudinal, intra-individual monitoring of renal function in pediatric transplant recipients.
• Both cystatin C and serum creatinine are viable markers for assessing GFR changes post-transplant.
• Further studies with larger cohorts may clarify the role of CysC in specific transplant scenarios.