Correlations between serum kidney injury molecule-1,cystatin C and immunosuppressants:A cross-sectional study of renal transplant patients in BahrainOA

Renal transplant patients receive several immunosuppressive drug regimens that are potentially nephrotoxic for treatment.Serum creatinine is the standard for monitoring kidney function;however,cystatin C(Cys C)and kidney injury molecule-1(KIM-1)have been found to indicate kidney injury earlier than serum creatinine and provide a better reflection of kidney function.Here,we assessed Cys C and KIM-1 serum levels in renal transplant patients receiving mycophenolate mofetil,tacrolimus,sirolimus,everolimus,or cyclosporine to evaluate kidney function.We used both the Chronic Kidney Disease Epidemiology Collaboration(CKD-EPI)2021 equation,which is based on creatinine and combined creatinine with Cys C,and the CKD-EPI 2012 equation,which is based on Cys C alone,to estimate glomerular filtration rate(GFR).Then,we assessed the association between serum KIM-1 and GFR<90 mL per minute per 1.73 m2.We observed significantly higher serum Cys C levels in patients with the elevated serum creatinine,compared with those with normal serum creatinine.The estimated GFRs based on creatinine were significantly higher than those based on the other equations,while a significant positive correlation was observed among all equations.Serum KIM-1 levels were negatively correlated with the estimated GFRs by the CKD-EPI Cys C and the combined creatinine with Cys C equations.A serum KIM-1 level above 0.71 ng/mL is likely to indicate GFR<90 mL per minute per 1.73 m2.We observed a significant correlation between serum creatinine and Cys C in our renal transplant patients.Therefore,serum KIM-1 may be used to monitor renal function when using potentially nephrotoxic drugs in renal transplants.