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The Necessity for Continued Research in Older Renal Transplant Recipients

Smith, Byron PhD1

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doi: 10.1097/TP.0000000000003843
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Sandal et al1 assess trends of kidney retransplant recipients >65 y of age in the United States using national registry data in their article “Evolving trends in risk profiles and outcomes in older adults undergoing kidney re-transplantation.”1 To quantify trends, transplants were split into 3 eras representing distinct periods of Organ Procurement and Transplantation Network policies: 1995–2002, 2003–2014, and 2015–2016. Contrary to the increasing trends in counterfactuals to transplant outcome such as donor and recipient age, donation after circulatory death donors, and calculated panel reactive antibody, the authors show that transplant outcomes are improving among elderly kidney retransplant recipients. There is a current dearth of articles exploring kidney retransplant in adults >65 y of age, which this article begins to fill.

The dominant improvement in transplant endpoint was the cumulative incidence of mortality within 3 y of the retransplant, which is also the largest cause of graft loss in this population. Interestingly, a similar decreasing trend existed in death-censored graft loss (13.3% to 10.0% to 5.1%) although this was not statistically significant, likely due to much smaller numbers. In addition, the authors acutely identify some disconcerting trends, such as a 5-y death-censored graft loss incidence that is much higher in living donor transplants (29.4%) versus deceased donor transplants (19.9%).

The number of candidates older than 65 y of age has been steadily increasing since 1995. Recipients of living donor kidneys will often receive organs from older donors than younger recipients, possibly due to a reduced social network. Sandal et al speculate that access to prospective organs has improved for older kidney recipients after initial graft failure. This is evidenced by the fact that “the proportion of non-White re–kidney transplant recipients and those living with assistance has increased and so has the median recipient age and body mass index.”

While these results paint an optimistic picture of trends in older kidney retransplants, conclusions from national registry studies are limited. One critical issue associated with transplant in an older population is physical and cognitive well-being that can be challenging to objectively measure at a national level. Several measures of physical health such as the Short Form 36 physical function score or measures of frailty have been used previously. Cognitive impairment has also been shown to impact graft survival after transplant. These measures may be well established in patients’ first transplantation, but it is unclear the extent to which they play a role in retransplantation. Understanding the national trends in frailty and cognitive impairment for seniors getting transplanted or retransplanted may help guide practice.

Additionally, social support before and after transplantation is viewed as an important factor regardless of the age of the recipient. Older recipients often have a reduced social network that can make posttransplant recovery more challenging. Although quantifying the degree of social support that a patient has is difficult, the impact of social isolation can be large. An example would be the sharp spike in deaths related to Alzheimer’s disease or dementia during the current COVID-19 pandemic.2

This pandemic has had a disproportionate impact on the older demographic and tracking the trends from the article by Sandal et al will be critically important to understand the ongoing trends for seniors. Removing this major confounding factor in future studies will be difficult. For example, 2020 was the first year that the number of kidney waitlist additions for adults over 65 y of age declined (based on Organ Procurement and Transplantation Network data accessed on May 17, 2021). Whether this may be related to transplant rate improvements or a diminishing prospective waitlist pool remains unclear.

REFERENCES

1. Sandal S, Ahn JB, Cantarovich M, Chu NM, Segev DL, McAdams-DeMarco MA. Evolving trends in risk profiles and outcomes in older adults undergoing kidney re-transplantation. Transplantation. 2022;106:1051–1060.
2. Woolf SH, Chapman DA, Sabo RT, et al. Excess deaths from COVID-19 and other causes, March–July 2020. JAMA. 2020;324:1562–1564.
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