Cyclosporine trough (C0) and 2-hour postdose (C2) levels: Which one is a predictor of graft loss?
Background. Compared with conventionally measured trough level (C0), cyclosporine 2-hour postdose (C2) concentrations show a better correlation with the area under the curve and acute graft rejection. Objectives. We evaluated the relationships of C0 and C2 with long-term graft survival among kidney transplant recipients. Methods. In a case-control design, we selected 215 adult kidney recipients. Inclusion criteria were more than 18 years of age at transplantation and at least 6 months of follow-up. The case group consisted of patients with graft loss (n = 17) and a control group, patients with functioning grafts (n = 198). The C0 and C2 levels for the first 6 months posttransplantation, along with demographic and clinical data, were compared between the two groups using univariate analysis. P < .05 was considered to be significant. Results. The mean age at transplantation was 40.5 +/- 16.5 years. The mean follow-up duration was 18 14 months. The mean C0 values for the case and control groups were 257.8 +/- 126.5 and 248.5 +/- 104.4 mu mol/L, respectively (P > .05). The values for C2 were 712.7 +/- 273.2 and 886.2 +/- 266.9 mu mol/L, respectively (P = .01). Conclusions. We observed that C2, but not C0, in the first 6 months posttransplantation were a predictor of long-term graft survival. The findings here in supported the results of other studies that have proposed cyclosporine concentration monitoring by C2 rather than C0 measurements.