Factors predisposing to post-renal transplant erythrocytosis: a retrospective study.

A retrospective study was conducted on 143 consecutive renal transplant recipients who had a functioning graft for three months or longer, to evaluate the prevalence of post-transplant erythrocytosis (PTE) and its potential risk factors. True PTE was defined as hematocrit (Ht) above 52% and hemoglobin (Hb) above 18 g/dl in males, and Ht above 50% and Hb above 17 g /dl in females. A total of 31 patients (21.6%) developed PTE; none had any evidence of polycythemia vera (PV), or secondary polycythemia due to reduced arterial oxygen, kidney or hepatic tumors, or relative erythrocytosis due to a decrease in plasma volume by overuse of diuretics. Thirty-one non-polycythemic patients (Hb 12.9 +-1.6 g/dl) matched for sex, age and renal function were used as case controls. PTE was more common in males (p= 0.043). The majority of our patients developed PTE within the first year post-transplantation and all had excellent renal function at the time of diagnosis. Also, PTE was found to be related to duration on dialysis prior to transplantation (p= 0.0013) and acute rejection (p= 0.0031).