A Prospective Study of Anaemia and Long-term Outcomes in Kidney Transplant Recipients

Background: Anaemia is prevalent in kidney transplant recipients (KTR), and only few KTR with anaemia receive treatment with erythropoietin. Some have claimed that this undertreatment might contribute to suboptimal outcomes such as mortality and cardiovascular events in these patients. However, no evidence is currently available that anaemia is actually associated with such risks in KTR.

Methods: We merged two cohorts of KTR to study the associations between anaemia and two outcomes: all-cause mortality and kidney allograft loss. Detailed information on the demographic and clinical characteristics of these 825 patients was available at baseline. As recommended by the American Society of Transplantation, anaemia was considered present if the haemoglobin concentration was < or =13 g/dl in men or < or =12 g/dl in women. Patients were followed using the Austrian Dialysis and Transplant Registry.

Results: After 8.2 years of follow-up, 251 patients died and 401 allografts were lost. In multivariate analyses, anaemia was not associated with all-cause mortality (HR: 1.08; 95% CI: 0.80-1.45), but it was associated with 25% greater risk of allograft loss (HR = 1.25; 95% CI: 1.02-1.59). This association was even more pronounced in death-censored analyses. Analyses using haemoglobin as a continuous variable or in categories also found no association with mortality.

Conclusions: Anaemia may not be associated with mortality in KTR. In light of the recent findings of increased mortality in chronic kidney disease patients with higher haemoglobin treatment target, further evidence is needed to guide clinicians in the treatment of anaemia in these patients.