Cystatin C : An Important Biomarker for Evaluating Early Renal Dysfunction in the Hypertensive Patients of Kolkata , West Bengal

Abstarct: Background: Hypertension has been recognized as one of the causes of Chronic Kidney Disease as it contributes to 40% of all CKD cases. Cr and eGFR calculated from creatinine based equation has been in practice for diagnosis and treatment of CKD for ages. Cystatin C, a polypeptide synthesized by all nucleated cells has been found to play a major role in detection of early renal impairment in hypertensive nephropathy patients. Objective: To compare the role of serum creatinine and cystatin C in diagnosing early CKD. Method: A total of 88 hypertensive patients and 70 controls were enrolled in the study. HTN patients were grouped as Stage I and Stage II on the basis of their blood pressure. eGFR was calculated by different equations based on estimated serum creatinine and cystatin C. Results: The serum creatinine, cystatin C and blood pressure of the subjects were observed to be much higher in both stage I and stage II hypertensives as compared to their controls (cr: 1.29±0.56 &1.54±0.91 vs 0.72±0.13; cysC: 1.42±0.82 &1.98±1.02 vs 0.76±0.21; SBP: 142.33±13.2 & 167.57±8.5 vs 128.89±14.1). Cystatin C showed more positive correlation with SBP (r= 0.323; p=0.0092) than creatinine (r=0.1068; p=0.3617 [NS]). An inverse association of eGFR with both creatinine and cysC was found in the hypertensive in comparison to their peer normotensives (58±17.6 & 54.48±25.32 vs 107.41±19.14). But cysC based eGFR was much reduced than creatinine based one thus indicating its importance in early detection of CKD. Conclusion: Serum cystatin C was proved to be a better predictor of CKD than creatinine among hypertensive patients.