A comparison between serum creatinine and cystatin C-based equations for estimation of graft function

Area of Science:

• Nephrology
• Transplantation Medicine
• Biomarker Research

Background:

• Optimal management of kidney transplant (KT) patients relies on accurate estimated glomerular filtration rate (GFR) monitoring.
• Creatinine and cystatin C are commonly used biomarkers for GFR estimation.
• Creatinine clearance (CCr) via 24-hour urine collection serves as a reference standard.

Purpose of the Study:

• To compare the predictive performance of creatinine- and cystatin C-based GFR equations against CCr in KT recipients.
• To evaluate the accuracy, precision, and bias of different GFR estimation formulas.
• To assess the concordance in classifying graft function using Kappa statistics.

Main Methods:

• GFR was calculated using Le Bricon and Stevens (cystatin C-based) and Cockcroft-Gault (CG) and MDRD (creatinine-based) equations.
• 173 kidney transplant recipients were included in the study.
• Statistical analyses included bias, precision, accuracy, and Kappa statistics for concordance.

Main Results:

• Cystatin C-based equations (Stevens, Le Bricon) demonstrated higher accuracy (87.9%, 83.8%) within 30% of CCr.
• Stevens and Le Bricon equations showed better precision and lower bias compared to creatinine-based equations.
• Kappa statistics indicated higher concordance for cystatin C-based equations (0.53) versus creatinine-based (CG: 0.48, MDRD: 0.40).

Conclusions:

• Cystatin C-based GFR equations exhibit superior predictive performance for kidney transplant graft function.
• These findings suggest cystatin C is a valuable biomarker for monitoring KT recipients.
• Further investigation into the role of cystatin C in graft function monitoring is warranted.