Serum Cystatin C in Chronic Kidney Disease: A Case-Control Study

Background: Chronic kidney disease (CKD) is a major public health concern in recent years mainly due to its adverse clinical outcomes. It is most commonly attributed to diabetes mellitus (DM) and hypertension (HTN). Among the several novel biomarkers discovered to detect impaired renal function, serum cystatin C (SCysC) has gained importance. Objectives: The aim of the study was to compare SCysC and serum creatinine (SCr) in CKD subjects and apparently healthy controls. Methods: This case-control study comprising of 120 diagnosed cases of CKD and 40 controls was conducted at a tertiary care hospital. SCr and SCysC levels were estimated using modified Jaffe’s method and particle enhanced immunoturbidimetric method, respectively. Estimated glomerular filtration rate (eGFR) was calculated using CKD EPI formula. Comparison of SCr and SCysC between cases and controls was done using Mann Whitney U test. Pearson’s correlation test was used to study the correlation between variables. Statistical significance was considered at P<0.05. Results: Both SCr and SCysC levels were higher in cases compared to controls (P<0.001). In the group comprising of Stage 1 and Stage 2 CKD subjects, all the subjects showed normal SCr levels, while 96.8% of the subjects showed elevated SCysC levels. SCysC (r=-0.800) showed better correlation than SCr (r=-0.724) with eGFR (P<0.001). A strong correlation was found between SCysC and SCr levels (r=-0.887, P<0.001). Conclusion: SCysC is a good indicator of renal dysfunction and may be used to screen patients with long duration of DM or HTN for CKD.