Relationship between changes of calcineurin inhibitor levels and serum creatinine and cystatin C levels in kidney transplant patients

Abstract

Background : Calcineurin inhibitors (CNI: cyclosporine, tacrolimus) are major immunosuppressants used in kidney transplant (KT) patients. Nephrotoxicity is an important side effect of CNI. The elevation of serum creatinine (Scr) is a biomarker for nephrotoxicity. However, there are several factors that affect changes of Scr. It is believed that serum cystatin C (Scys C) would be a better biomarker.

Objective : To investigate the relationship between changes of CNI levels and Scr and Scys C levels in KT patients.

Design : Descriptive study

Setting : Division of Nephrology, Department of Medicine, Phramongkutklao Hospital

Patients and Methods : Patients who received KT for at least 3 months, and during steady state. Blood samples were collected for determining cyclosporine and tacrolimus trough levels, Scr and Scys C levels.

Results : 217 serum samples were analysed from 56 patients (43 male, 13 female). The results showed that the changes of CNI levels were not correlated with the changes of Scr (r = -0.103, P = 0.194) and Scys C (r = -0.107, P = 0.176) levels.

Conclusions : Patients who received KT for a long time until the steady state, the slightly changes of CNI levels, no influence on the changes of Scr and Scys C levels. Therefore, biomarker can be used both Scr and Scys C