Comparative Evaluation of Kidney Function Using Cystatin C and Serum Creatinine in Cirrhosis Patients: A Prospective...

Accurate assessment of kidney function in patients with cirrhosis remains challenging due to the limitations of traditional biomarkers. This study aimed to compare the utility of serum creatinine (Cr) and cystatin C (Cys) in evaluating kidney function across different stages of disease severity.

This prospective cross-sectional study enrolled 120 participants at Jinnah Postgraduate Medical Centre, Karachi, Pakistan, comprising 30 healthy controls and 90 patients with cirrhosis, equally distributed across Child-Pugh Classes A, B, and C. Comprehensive clinical assessment included measurement of serum Cr and Cys, with estimation of glomerular filtration rate (eGFR) using CKD-EPI 2021 equations based on Cr, Cys, and combined Cr-Cys. The Cr/Cys ratio was calculated to assess the degree of discordance between these biomarkers and kidney function was further classified into chronic kidney disease (CKD) stages according to the respective eGFR estimation methods.

Serum Cr was elevated in cirrhosis than controls with no difference between patient groups, whereas Cys showed a progressive increase with advancing cirrhosis and disease severity (p < 0.001). The Cr/Cys ratio decreased consistently with increasing cirrhosis severity across groups, showing discordance between the two biomarkers. Correspondingly, Cys-based and combined Cr-Cys CKD-EPI equations showed stepwise declines across Child-Pugh Classes. Cr-based equations predominantly classified patients as early-stage CKD, while Cys-based and combined equations identified more advanced dysfunction.

Cys, alone or integrated with Cr in CKD-EPI equations, provides a more sensitive assessment of kidney dysfunction with increasing cirrhosis and disease severity.