Post-Transplant Polycythemia: Incidence, risk factors and prognosis

Abstract

Purpose: To assess the incidence of post transplant polycythemia (PTxP) in the first year post transplant in a series of renal transplant recipients and identifying risk factors and prognosis. Methods: Retrospective, observational study. Criteria included: renal transplant from January to December 2010, age >18 years at transplant, post-transplant follow-up >6 months. Criteria of exclusion: obstructive lung disease, active smoking and secondary erythrocytosis. For the analysis, patients were divided in 2 groups: Polycythemia (PTxP) Hb ≥ 18g/L or htc≥51% (male) or Hb≥17g/L or Htc≥50% (female). Severe PTxP was defined as hb>18,5g/L or htc>55% and/or need of phlebotomies. Control group (CTL): Hb<18g/L or htc<51% (male) and hb<17g/L or ht<50% (female). Data analyzed included demographic information, thromboembolism, laboratory data such as hemoglobin, hematocrit and serum creatinine, therapy and adverse events. Results: 122 patients, 47   12 years old, majority male (63,1%) and recipients of kidneys from deceased donors (95%) fulfilled the inclusion criteria. Seventeen patients (14%) were classified as PTxP (Hb 17,3 0,6 g/L; Htc 53,4 1,9%), diagnosed 9   5 months after transplant. Six patients classified as bearers of severe PTxP were free of thromboembolic events or need for phlebotomies during the follow-up. Up to 62% patients presented normal renal function (serum creatinine < 1,6 mg/dL) after the 6 months follow up. PTxP therapy included ACEi or amminophylline in 12/17 patients, with complete remission in 8. From 5 untreated patients, 4 had complete spontaneous remission. PTxP and CTL groups had comparable demographic data, blood pressure, renal function and were under similar immunossupressive therapy. In addition, the incidence of diabetes and smoking was similar between groups. In the PTxP group, anemia recovered earlier than in CTL group, despite of presenting similar renal function. The 3-year graft and patient survival was similar between groups with a trend to earlier graft loss in CTL group. Conclusion: The incidence of PTxP in this series was 14%, lower than previous report from our group of 33%. The near normal hemoglobin level range within the first month post transplant was the only marker for the PTxP risk in this series.