Percentage of hypochromic red blood cells is an independent risk factor for mortality in kidney transplant recipients.

There are no published studies on the associations between anemia or iron status parameters and important long-term outcomes in kidney transplant recipients (KTR). We prospectively studied 438 KTR from a large transplant clinic for all-cause mortality and kidney allograft loss. Hemoglobin and iron status parameters (serum iron, transferrin, transferrin saturation, ferritin, percentage of hypochromic red blood cells [%HRBC]) were assessed at baseline as were important demographic, clinical and laboratory characteristics. The Austrian Dialysis and Transplant Registry and the Eurotransplant database were used to ascertain immunological and transplantation-related parameters and to ascertain death and allograft rejection. Cox proportional hazard models were used for analyses. Over 7.8 years of follow-up, 129 deaths (29.5%) occurred and 208 grafts (47.5%) were lost. From multivariate analyses, we found that anemia (hemoglobin <10g/dL) was not associated with mortality or graft loss. Among the iron status parameters, only %HRBC was associated with greater all-cause mortality. Patients with HRBC >10% had twice the mortality risk (HR: 2.06; 95%CI: 1.12-3.79) compared to patients with HRBC <5%. Neither of the iron status parameters were associated with allograft rejection. In conclusion, we found that %HRBC was an independent risk factor for mortality in KTR, while other iron status parameters or anemia were not associated with risk. Larger studies on the association between anemia and these outcomes are warranted.