Comparison of serum levels of Cystatin-C and traditional renal biomarkers for the early detection of pre-hypertensive nephropathy.

Objective: To compare serum Cystatin-C and serum creatinine levels along with estimated glomerular filtration rate of apparently healthy people of South Asian descent with pre-hypertension to determine which is better in detecting reversible renal dysfunction.

Methods: :The comparative cross-sectional study was conducted at the Army Medical College, Rawalpindi, Pakistan, in 2013-14, and comprised apparently normal healthy male and female volunteers. The subjects were divided into normotensive group 1 and pre-hypertensive group 2. Serum Cystatin-C levels were measured by sandwhich enzyme-linked immunosorbent assay technique whereas serum creatinine levels were measured by Jaffe's procedure. Glomerular filtration rate estimation was done by using standard equations. SPSS 20 was used for data analysis.

Results: Of the 78 subjects, 39(50%) were in normotensive group 1 and 39(50%) in the pre-hypertensive group 2. The mean age was 38.74 } 5.71 years in group 1 and 38.07 } 3.84 years in group 2. Serum Cystatin-C levels were higher in group 2 than in group 1(p= 0.0001), whereas serum creatinine levels manifested no statistical difference between the groups (p=0.106). Estimated glomerular filtration rate based on Cystatin-C significantly decreased in group 2 than in group 1 (p=0.0001). Serum Cystatin-C displayed a significant positive correlation and estimated glomerular filtration rate based on Cystatin-C negative correlation with the rising blood pressure values (p=0.0001).Serum Cystatin-C reflected a very high sensitivity and specificity at a cutoff value of 0.77 mg/l compared to serum creatinine.

Conclusions: Serum Cystatin-C and Estimated glomerular filtration based on rate Cystatin-C appeared to be better renal biomarkers in the detection of pre-hypertensive nephropathy.