Post-transplant renal anemia: a call to action from a national study in routine clinical practice

Background: Post-transplant anemia is a prevalent yet often overlooked condition that poses significant risks. Current guidelines consider the same treatment recommendations and goals for these patients as for chronic kidney disease patients not on dialysis. Previous reports demonstrated a lack of awareness and suboptimal management, indicating a pressing need for improvement. We therefore wanted to update the information on post-transplant anemia. We aimed to describe the present state of anemia management, goals and adherence to guidelines within a representative sample of the kidney transplant (KTx) population.

Methods: We designed a retrospective nationwide multicenter study including outpatients from eight KTx hospitals. Nephrologists gathered data from electronic medical records encompassing demographics, comorbidities, KTx characteristics and immunosuppressive therapy, and information pertaining to anemia management (laboratory values, previously prescribed treatments and subsequent adjustments). The European statement on the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines was the reference for definitions, drug prescriptions and targets. Anemia occurring within the initial 6 months post-transplantation was classified as early onset.

Results: We included 297 patients with post-transplant anemia aged 62.8 years (standard deviation 13.6), 60% of whom were male. They had received a graft from cardiac death or brain death donors (61.6% and 31.1%, respectively) a median of 2.5 years (0.5-8.7) before. Among them 77% (n = 228) were classified as having late post-transplant anemia, characterized by a higher prevalence of microcytic and iron deficiency anemia. A total of 158 patients were on erythropoietic-stimulating agents (ESAs) treatment, yet surprisingly 110 of them lacked iron supplementation. Notably, 44 patients had an indication for iron supplementation and among them, 30 exhibited absolute iron deficiency. Out of the 158 patients receiving ESAs, only 39 surpassed the limit for the ESA resistance index, indicating poor response. This resistance was more frequent among patients with early post-transplant anemia (26.1% vs 9.2%). We have identified iron profile, early post-transplant anemia and estimated glomerular filtration rate as factors associated with the highest risk of resistance.

Conclusion: We found that hemoglobin targets are individualized upwards in post-transplant anemia. In this setting, iron therapy continues to be underutilized, especially intravenous, and iron deficiency and prior events (blood transfusion or hospital admission) explain most of the hyporesponsiveness to ESA. This highlights missed opportunities for precise prescription targeting and adherence to established guidelines, suggesting a need for improved management strategies in post-transplant anemia patients.