Abstract
Background and Aims
A growing number of end-stage renal disease patients waiting for a kidney transplant (KT) are older than 50 years old. Consequently, many kidney transplant recipients will be in need of dialysis or re-transplantation at an older age. For young patients, re-transplantation offers an advantage over dialysis but in the elderly these benefits are not well established. For selected older recipients, with rigorous cardiovascular and neoplastic evaluation, immunosenescence might actually provide an advantage in graft outcomes. Our aim was to compare major clinical outcomes between patients older and younger than 60 years old at re-transplantation, and between first and second KT for recipients older than 60 years old.
Method
We performed a retrospective, longitudinal study, that included all patients submitted to a second KT between January 2008 and December 2019, excluding patients with more than 2 grafts or multi-organ transplant. We defined two groups according to recipient’s age at re-transplant, older and younger than 60 years-old, and compared major clinical outcomes such as biopsy proven acute rejection, death-censored graft survival and patients’ survival. Afterwards, we selected KT patients older than 60 years, and compared the same outcomes for patients with first and second KT. Follow-up time was defined at 1st June 2020 for functioning grafts or at graft failure (including death with a functioning graft).
Results
We included 109 patients with a second KT, 13 (12%) older than 60-years-old (group 1), with a mean age of 62.85 ± 2.9 years, and 96 (88%) younger than 60-years-old (group 2), with a mean age of 40.4 ± 10.6 years. Group 1 recipients were all male (100% vs 59.4%; p=0.004) and had higher body mass index (25±2.8 vs 22.5±3.6 kg/m2, p=0.016). Recipients from the group 1, waited less time for their second KT (37.7±21.8 vs 64.8±58.8 months; p=0.003), but had older donors (59.5±13.5 vs 45.9±11.5 years old; p<0.001), and significantly more expanded-criteria donors (76.9% vs 26%; p<0.001). HLA mismatch and PRA (%) were similar for both groups. Regarding biopsy proven acute rejection, there were no events for older patients compared to 21 patients (22%) for the younger group (p<0.05). Death censored graft survival was similar for both groups (logrank test p=0.124) with similar 1 year and 5 years graft survival (group 1: 91.7%, 82.5% versus group 2: 90.1%, 85.2% p=0.944). We found no difference in patients’ mortality at follow up between both groups (logrank test p=0.0124). Focusing on differences between re-transplantation (group 1, N=13) and first kidney transplant (group 2, N=390) in patients older than 60-year-old, there were more males in group one, but we found no other differences in recipient and donor demographic characteristics, or waiting time for kidney graft (38±22 versus 47±25 months, p=0.17). As expected, PRA was significantly higher in group 1 (25 ±29% vs 3.7±11%, p=0.018) but there were no differences in HLA matching. At follow-up, the mean time post-transplant for group 1 was 47±39.68 and for group 2 was 63 ±39.9 months (p=0.144). There were no differences regarding acute rejection episodes (0% vs 3.1%; p=0.521) or death censored graft survival was similar at 1 and 5 years (group 1: 91.7%, 82.5% versus group 2: 93.4%, 86.3% p=0.983).
Conclusion
In carefully selected patients, advanced age should not be a contraindication to kidney re-transplantation. Immunosenescense might lead to lower acute rejection rates and older donors might be used with less restrictions. In our study, major clinical outcomes were comparable to their younger counterparts with a second graft and to older patients with a first graft.
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