performance of creatinine and cystatin c-based equations to estimate kidney function in renal transplant recipients

Background: numerous equations are applied in order to estimate the glomerular filtration rate (gfr). objectives: this study aimed to spot the optimal equation that accurately estimates gfr and, therefore, the chronic kidney disease (ckd) stage in renal transplant patients. methods: this cross-sectional study was conducted on 58 renal transplant patients. their venous blood samples were obtained for serum creatinine and cystatin c determination used to calculate estimated gfr (egfr). the average contrast of gfr in each equation was calculated using the bland-altman method. the correlation, bias, imprecision, and 10% and 30% accuracy were compared between the egfr cystatin c and creatinine. concordance between both equations for ckd staging was assessed. the classification of patients was also investigated. results: bland-altman plots and bias demonstrated that egfr by the abbreviated modification of diet in renal disease (ab-mdrd) was the most accurate compared with chronic kidney disease epidemiology collaboration (ckd-epi) cystatin c, followed by ckd-epi egfr creatinine. with reference to ckd-epi cystatin c, the imprecision of the equations was approximately similar to ab-mdrd, and ckd-epi creatinine is still better than the cockcroft-gault (cg) formula. they also showed good 30% accuracy. finally, our finding suggested that ab-mdrd and ckd-epi egfr creatinine might be the best-performing equation in the classification of the ckd stages in a cutoff of 60 ml/min/1.73 m 2. conclusions: due to the high cost and potential delay in measuring cystatin c, it would be much more appropriate to measure ab-mdrd; after that, ckd-epi egfr creatinine as an alternative approach in order to facilitate rapid clinical decision in renal transplant patients.