Introduction: Since the 1970’s, the use of transfusions in kidney transplant medicine has been a point of contention. While they are a solution to the anaemia plaguing this patient population and in 1978 were shown to lead to a dose-dependent improvement in graft survival, they also have the ability to induce a sensitized state, increasing the risk for poorer graft outcomes. Influenced by the inherent risk, clinicians have begun to administer transfusions based on clinical need as opposed to deliberately. Furthermore, the popularity and efficacy of tacrolimus as an immunosuppressant over the past two decades, has allowed for a degree of standardization across different kidney transplant centres. The majority of the studies in the past two decades have focused on previously understudied postoperative blood transfusions, occurring in 40-60% of cases. No systematic reviews or meta-analyses have been published including these newer studies. With these details in mind we believed it prudent to undertake a systematic review and meta-analysis exploring the effect transfusions have on transplant outcomes.

Methods: A systematic search was conducted using MEDLINE, Embase, Cochrane library and Clinicaltrals.gov. Including only English articles published between 1/1/2000 and 01/03/2022, we found 9 studies that met our inclusion criteria. A meta-analysis was thereby carried out for three outcomes, delayed graft function (DGF), the development of de novo donor specific antibodies, and antibody mediated rejection (AMR).

Results: Low-level evidence exists for no difference or an increase in DGF and AMR for participants who received at least one blood transfusion. Low-level evidence exists for an increase in AMR for participants who received at least one blood transfusion. For the outcomes not included in the meta-analysis (graft loss/failure, graft survival, acute rejection, development of HLA-Abs, sepsis), each of the included studies reported either no difference or a detrimental effect on the outcomes. No study reported any improvement with blood transfusion usage.

Conclusion: The transfusion effect appears not to exist in the 21st century even in patients receiving postoperative blood transfusions. However, while transfusions are avoided wherever possible and despite a myriad of replacements becoming available, transfusions in kidney transplant recipients do not appear to be associated with any worse outcomes compared to their non transfused counterparts. While more research is required, clinicians may be able to administer blood transfusions to kidney transplant patients with a clear conscience.