However, ESP recipients had a greater risk of acute rejection, including late rejection, presumably related to a greater degree of human leukocyte antigen (HLA)-mismatch, which OSI-906 in vivo was not considered an important factor in the allocation of ESP kidneys. The 1 and 5 year death-censored graft survival in ESP recipients were similar to ‘old-to-any’ recipients

(1 year – 83% and 81%, respectively; 5 years – 67% for both groups) but were inferior compared with ‘any-to-old’ recipients (1 year 90% and 5 years 81%) (Table 2). When stratified by donor age, the 1 and 5-year graft survival in the ESP group was 75% and 47% compared with 74% and 53% for ‘any-to-old’ recipients with older donors aged ≥60 years (P = 0.38) and 85% and 67% for ‘any-to-old’ recipients with younger donors aged < 60 years (P < 0.001) suggesting older recipients receiving older donor kidneys allocated through the ETKAS had similar outcome as ESP recipients. Although the risk of DGF was reduced in ESP recipients, DGF remained an important predictor of acute rejection, graft and patient survival indicating that DGF may have a greater negative impact on graft outcome in older recipients receiving older donor kidneys. It is plausible that strategies to reduce GSI-IX the risk of

DGF in ESP recipients (e.g. to further reduce cold ischaemia and tailoring immunosuppressive regimens to avoid initial calcineurin-inhibitor use) may lead to an improvement in graft and patient outcomes. An important and often overlooked finding in this study is that younger recipients of older donor kidneys have reduced survival, similar to that of the ‘any-to-old’ recipients. However, before the creation of ESP, there was already a degree of age-matching occurring during the ETKAS allocation process, such that the very young donor kidneys were seldom allocated to older recipients. Similar practice also occurs in countries

such as the USA and Australia where age-matching is not part of the standard allocation process.31,34 Eurotransplant Senior DR-compatible Interleukin-3 receptor Program is a new future initiative of the ESP to preferentially allocate kidneys to recipients with 0 HLA-DR mismatches and therefore potentially reducing the risk of rejection.35 The outcome of this approach will be prospectively evaluated in the coming years. Similarly, a retrospective study of 1269 deceased donor renal transplant recipients demonstrated that actual graft survival was significantly reduced in younger recipients ≤55 years receiving older donor kidneys >55 years as compared with all other groups (P = 0.001; RR, 1.97; 95% CI, 1.32–2.94), including older recipients >55 years receiving older donor kidneys >55 years.26 Retrospective analysis of the OPTN database demonstrated that for every 1 year increase in donor age, the risk of graft failure (HR 1.01, P < 0.001) and death with functioning graft (HR 1.004, P < 0.001) was significantly increased.