Evaluation of serum Cystatin C as an early diagnostic marker in non-dialysis CKD patients as compared to serum creatinine.

Abstract

Objective: To test the hypothesis that Serum cystatin C is an early diagnostic marker in non-dialysis CKD patients as compared to serum creatinine. Study Design: Descriptive, Cross Sectional OPD/ Hospital Based study. Setting: Department of Biochemistry and Nephrology, Jinnah Postgraduate Medical Centre, Karachi. Period: January 2018 to December 2018. Material & Methods: Study subjects included the diagnosed cases of Chronic Kidney Disease (CKD) up to 4^th stage with exclusion of patients on dialysis. A total 90 subjects of age above 18 years who were presenting to the Nephrology clinic of JPMC for screening and evaluation of chronic kidney disease were recruited after applying inclusion and exclusion criteria. Results: There was significant mean difference in all eGFR across studied groups with p-value lower than 0.05. Cystatin C based calculation of GFR is lower in all three groups (86.33±13.08, 18.73±8.44, 73.30±12.23) as compared to GFR calculated based on serum creatinine (102.33±17.84, 30.00±11.59,. Our study was also suggestive that the sensitivity of serum Cystatin C is higher as compared to creatinine for detection of reduced GFR. Conclusion: Our study shows that cystatin C is a reliable indicator of estimating kidney functions as compared to serum creatinine. A possible advantage of cystatin C is that being a large molecule, its blood levels might rise sooner than that of creatinine.