Background: The commonest cause of renal transplant loss is death with a functioning graft, usually from an excess of cardiovascular disease (CVD). Anaemia is becoming increasingly recognized as a reversible risk factor for the development of CVD. The purpose of this study was to estimate the prevalence of post-transplantation anaemia (PTA) in a large population of stable adult and paediatric renal transplants in one centre and to correlate the estimated glomerular filtration rate (eGFR), iron indices and the use of immunosuppressants with the prevalence of anaemia.
Methods: Every adult and paediatric patient with a functioning renal transplant and more than 3 months post-engraftment at Guy's hospital, London, as of 31 December 2004 and who had a valid creatinine and haemoglobin, in the period 1 September-31 December 2004 inclusive, was identified. A large database of clinical and biochemical indices was built up on the basis of medical notes and electronic patient records. Results were analysed for the prevalence of anaemia and risk factors for its development. Anaemia was defined according to the WHO criteria. All patients on treatment with an erythropoiesis stimulating agent were classified as anaemic, irrespective of haemoglobin.
Results: A total of 878 adults and 73 children were identified. Mean haemoglobin in adults was 12.9 +/- 1.6 g/dl and 11.8 +/- 1.4 g/dl in the children. Mean eGFR was 49.3 +/- 20.1 ml/min in adults and 65.7 +/- 18.8 ml/min in the paediatric cohort. Haemoglobin correlated positively with the eGFR in both cohorts (R = 0.33 and 0.29 in adults and children, respectively (P < 0.0001 for both)). We identified anaemia in 45.3% of adults and 22% in children. Ferritin levels were lower in children than in adults (79 +/- 93 vs 204 +/- 353 mg/l), but were higher in both cohorts among the non-anaemic populations than in those with anaemia. 58% of adults taking mycophenolate mofetil (MMF) were anaemic compared with 22% of children. One child, and 68 adults, were on recombinant erythropoietin. Multiple regression analyses identified age, female gender, eGFR and serum ferritin levels as independent predictors of haemoglobin in adult subjects.
Conclusions: The prevalence of PTA was high in both adult and paediatric cohorts while comparatively few patients were being treated with erythropoiesis stimulating agents. The strongest predictors of haemoglobin in this cohort of patients were age, female sex and graft function. Immunosuppression including MMF or sirolimus was associated with a higher prevalence of anaemia, but this was likely to be the result of poorer graft function in these subjects. Iron deficiency did not seem to be a causative factor for anaemia in this population.