Background: Post-transplant erythrocytosis (PTE) is defined as persistently elevated hemoglobin (Hb) and or hematocrit levels that occur following renal transplantation in the absence of thrombocytosis, leukocytosis, or another potential cause of erythrocytosis. PTE occurs in 8 to 15 percent of renal transplant recipients and usually affects patients with well-preserved graft function.
Materials and Methods: To evaluate the prevalence and risk factors of PTE, we retrospectively analyzed the records of renal transplant recipients undergoing regular follow-up at our center for at least 6 months. Patients with a history of chronic obstructive pulmonary disease or malignancy were excluded. PTE was defined as Hb >17 g/dl. A total of 215 living-related renal transplant recipients were included.  The clinical and laboratory parameters were noted.
Results and Discussion: Thirty-eight (17.7%) out of 215 renal transplant recipients developed PTE. The mean age of the PTE group was 38.1± 9.4 years. The median time to onset of PTE was 9.5 (range 4-24) months post-transplant. The mean Hb at the time of diagnosis of PTE was 17.84± 0.54g/dl. There was a significant correlation of PTE with male sex, history of smoking before transplantation, history of ≥1 episode of acute rejection and cyclosporine (versus tacrolimus) containing triple-drug immunosuppression (p<0.05). There was not any significant correlation of PTE with age, blood pressure, renal function, HLA matching, induction immunosuppression regime, transplant renal artery stenosis or new-onset diabetes after transplantation (NODAT). Other pre-transplant factors including history of hypertension, diabetes mellitus, underlying renal disease, hemoglobin levels, blood transfusions, erythropoietin dose and duration of dialysis were not significantly correlated to PTE.
Conclusion: PTE was observed in 17.7% of renal transplant recipients. PTE developed more frequently within the first year of transplantation. In addition to male sex and history of smoking, episodes of acute rejection and cyclosporine containing immunosuppression were associated with PTE.