2012-05-15 - Do You Know? - Issue 13: Anemia after kidney transplantation; its prevalence, risk factors and patient survival: A time-varying analysis.
TTS Education Committee would like to draw your attention to the following articles:
Anemia after kidney transplantation; its prevalence, risk factors and patient survival: A time-varying analysis.
Jones H, Talwar M, Noguiera JM, Ugarte R, Cangro C, Rasheed H, Klassen DK, Weir MR, Haririan A.
Transplantation
2012; 93: 923 - 928.
A randomised controlled trial of intravenous iron or oral iron for posttransplant anemia in kidney transplantation.
Mudge DW, Tan KS, Miles R, Johnson DW, Badve SV, Campbell SB, Isbel NM, van Eps CL, Hawley CM.
Transplantation
2012; 93: 822 – 826.
Commentary by Dr. Helen Plimore (TTS Education Committee).
Anemia is common after kidney transplantation [1] and is associated with poor graft outcome and increased mortality [2]. Two recent papers further our knowledge on risk factors for anemia and treatment of iron deficiency anemia.
In the paper by Jones, 530 renal allograft recipients were retrospectively followed for a mean of 31 months aiming to elucidate the incidence of anemia at varying time points, in addition to examining factors associated with anemia and associations with patient and graft survival.
The prevalence of anemia using the WHO definition [3] was 89% at the time of transplantation, decreasing to 44.3% by 2 years after transplantation. The use of erythopoietic stimulating agents (ESA) decreased from 25.6% at one month to 8.23% at 24 months while ESAs were prescribed in only 30.9% of patients with grade 3 anemia (Hemoglobin (Hb) 9 -10mg/dL in males, Hb 8 – 9 mg/dL in females) and 51.2% with grade 4 anemia (Hb < 9g/dL in males and <8g/dL in females). Iron supplementation was used in 10.9% of patients early post-transplant and in 29.2% in the later period. Factors associated with a low Hb were African American race, iron and erythropoietin use and the use of prednisone while male gender, higher eGFR, higher serum bicarbonate levels and the use of ACE Inhibitors or Angiotensin II Receptor Blockers were associated with a higher Hb. Grade 4 anemia was an independent predictor of both graft failure and death, while the degree of anemia was significantly associated with the risk of death (HR 2.2 for grade 2 anemia, HR 3.9 for grade 3 and HR 4.8 for grade 4).
Despite anemia being commonplace, there is little in the literature examining treatment of anemia after kidney transplantation. Early after transplantation, anemia is often due to iron deficiency [4]. The second paper (Mudge et al), describes a prospective randomised controlled trial comparing IV iron polymaltose with oral ferrous sulphate with a primary outcome of time to resolution of anemia defined by a haemoglobin > 11g/dL in 104 patients. A key driver of the trial was perceived side effects of oral iron in terms of gastrointestinal side-effects and possible interaction with immunosuppressants.
Exclusions to the study included a previous reaction to IV or oral iron supplementation, and iron overload. 57% of patients were iron replete at the time of kidney transplant surgery. There was no significant difference in time to resolution of anemia between the two groups with a median of 12 days in the IV group and 21 days in the oral group (HR 1.22). Both oral and IV iron were well tolerated with no significant difference in the side effects although the study was not adequately powered to detect differences in adverse events. The authors conclude that IV iron does not appear superior to oral iron however it is possible that the degree to which iron deficiency was contributing to the anemia may have been less than anticipated. Additionally as adverse events were not powered adequately, in patients who have side effects from oral iron, IV iron appears a reasonable alternative.
Studies of post-transplant complications are often not undertaken and yet as clinicians, we spend a significant amount of time engaged in managing these problems. These studies demonstrate the importance of post-transplant anemia and offer practical treatment options that result in improvement in haemoglobin levels.
References:
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Yorgin PD, Belson A, Sanchez J et al. Unexpectedly high prevalence of posttransplant anemia in pediatric and young adult renal transplant recipients. |
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Molnar MZ, Czira M, Ambrus C, Szeifert L, Szentkiralyi A, Beko G, Rosivall L, Remport A, Novak M, Mucsi I. Anemia is associated with mortality in kidney-transplanted patients - a prospective cohort study. |
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World Health Organization. Worldwide prevalence of anemia 1993 - 2005: WHO global database on anemia vol 2011. In: de Benoist B, McLean E, Egli I, Cogswell M. eds |
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Poesen R, Bammens B, Claes K, Kuypers D, Vanrenterghem Y, Monbaliu D, Evenepoel P. Prevalence and determinants of anemia in the immediate postkidney transplant period. |