Clinical Assessment of Follow-Up Cystatin C-Based eGFR in Live Kidney Donors

Abstract

Purpose: We aimed to compare the cystatin C-based estimated glomerular filtration rate (eGFR) and the serum creatinine-based eGFR and to investigate the clinical roles of the cystatin C-based eGFR in assessing the follow-up renal function of kidney donors.

Materials and methods: We enrolled 121 healthy kidney donors who underwent live donor nephrectomy between October 2009 and December 2010 in a prospective manner. Serum creatinine and cystatin C were measured preoperatively and were followed after the surgery (1st, 4th, and 7th postoperative day and 1st, 3rd, 6th, and 12th postoperative month). We also compared the sensitivity and specificity of each eGFR method for predicting the development of chronic kidney disease (CKD) after donor nephrectomy.

Results: For those who had a Modification of Diet in Renal Disease postoperative day 4 eGFR of less than 60 ml/min/1.73 m(2), the probability of developing CKD was 89.0% (Chronic Kidney Disease Epidemiology Collaboration eGFR, 66.0%; Cockcroft-Gault eGFR, 74.0%; cystatin C eGFR, 57.1%). A cystatin C eGFR of below 60 ml/min/1.73 m(2) at postoperative day 4 predicted CKD at 6 months with a specificity of 90.3%, which was the highest among the estimation methods used. Cystatin C eGFRs were generally higher than the creatinine-based eGFRs.

Conclusions: We conclude that cystatin C-based estimations of the GFR are helpful for predicting the recovery of renal function in kidney donors and could be added to the follow-up protocol of kidney donors who may develop CKD, especially patients whose immediate postoperative renal function is marginal.

Keywords: Kidney function tests; Kidney transplantation; Living donors; Nephrectomy.

FIG. 1

Scattered plot of eGFR value distribution: (A) preoperative, (B) 6 months postoperative. Cystatin C-based values were generally higher than the other creatinine-based values. eGFR, estimated glomerular filtration rate; MDRD, the Modification of Diet in Renal Disease equation; CKD-EPI, the Chronic Kidney Disease Epidemiology Collaboration equation; GC, the Cockcroft-Gault equation.

FIG. 2

Receiver operating characteristic for CKD prediction by postoperative day 4 eGFR less than 60 ml/min/1.73 m². The area under the curve of the MDRD eGFR was the highest (0.845; 95% CI, 0.763 to 0.928); that of the cystatin C eGFR was the lowest (0.674; 95% confidence interval, 0.551 to 0.797). CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate; MDRD, the Modification of Diet in Renal Disease equation; CKD-EPI, the Chronic Kidney Disease Epidemiology Collaboration equation; GC, the Cockcroft-Gault equation.