Age Stratification of Deceased Donors Suggests Transplantation Opportunities for Countries

Optimal deceased donation at a national level necessitates a mixture of well-organized policies, successful public awareness campaigns with cultural backing, well-resourced hospital coordination, and a supportive legal framework.1 However, reaching this utopian vision seems to require more critically conceived metrics than what are commonly cited today. For example, deceased organ donation is frequently benchmarked simply around the number of organ donors per person in the country (either donors per million or donors per 10 000 deaths).2,3 Under this calculus, the Spanish system has gained deserving attention, and the United States has achieved more donation in recent years (Figure 1).FIGURE 1.: Approximate number of deceased organ donors from a sample of 9 countries in 2022. Sources: European Directorate for the Quality of Medicines and Health Care, International Registry in Organ Donation and Transplantation.Furthermore, capturing the nuances of how and why systems are gaining (or losing) donors requires consideration of societal differences and specific disease burden for the country in question. For instance, the most common cause of donor death may be stroke in a given country, while in another it may be head trauma or anoxic brain injury, which are typically younger, often ideal brain dead donors, impacting potential donor numbers dramatically.4 This cause-of-death diversity across different countries necessitates measurement of the age distribution to help identify best practices and strategies for organ donation. In this edition of Transplantation, Goldberg and colleagues stratify across age groups to characterize organ donation rates in North and South America and Europe in a retrospective cohort study of World Health Organization and national transplant system data.5 They estimated the potential increase if donation met the level of the highest performing age group from 17 countries and found that substantial areas and ages for improved organ donation exist. For example, in the United States, the greatest potential for increased donors per year was found at >8000 per year. Argentina, Germany, and Hungary had the largest potential for donation growth in terms of factor of improvement (ie, fold change or relative change). The authors aggregated donors generally by decade of life to form 7 groups (ages 0–19, 20–29, 30–39, 40–49, 50–59, 60–69, and ≥70) studying 17 selected countries across a 7-y period (2013–2019). More recent donors were not used as less consistent data were available, and the COVID-19 pandemic disrupted mortality rates. Likewise, data were limited such that donation type (cardiac death or brain death) was not feasible. Interestingly, the authors report that 14 of the 17 countries analyzed had similar age distribution of deaths, while there were three outliers in all age groups (Argentina, Hungary, and the United States). For instance, ages of donors in these three outlier countries had significantly less donors ≥70 y of age, higher numbers of donors 20–39 y of age (except Hungary), and much higher numbers of donors 40–59 y of age. The age groups 40–59 were most common in each country and there was significant variability of age group sizes across different countries with greatest variability in the percentage of donors ≥70 y of age. For example, in France and Spain, this age group was 10-fold higher than in Argentina and the United States where these were only 3% of the donor pool. Rates of donation without age stratification (measured as donors per 1000 deaths) were significantly different across the 17 countries with Spain having the highest rates—leading in most age groups. The United States was highest in the 0–19, 20–29, and 30–39 groups but markedly lower than Spain which led in groups 50–59, 60–69, and ≥70 y of age. Greatest potential for overall growth in donation was evident in the United States, Germany, Argentina, and the United Kingdom. The potential for relative increase was greatest for the ≥70 group in Hungary, United States, and Canada at 21.7, 9.5, and 8.1times current levels, respectively. In the United States, during the course of the study period, there was growth of donation at ages 30–49 compared with the growth in the donation rate of all ages. In 2023, in the United States, ages 60–69 and ≥70 were still considerably lower than Spain’s in 2019 even though this group had the highest number of deaths overall highlighting the group with the greatest potential for donation growth. The somewhat outdated period (2013–2019) analyzed is a clear limitation of this dataset; however, the statical constraints and the pandemic are common hurdles for this type of investigation. Other limitations in this reporting are a lack of more countries/continents, specific age groups (eg, 0-9), cardiac death versus brain death distinction, and confirmation of the ultimate denominator of deaths. Furthermore, organ utilization based on quality (eg, kidney donor profile index) across different age groups was not possible, but the authors do report that types of organ transplants were similar across the 17 countries. The risk tolerance for older donors is undoubtedly different globally, but age differences alone cannot explain the disparate donation rates as there is no apparent reason older donors would be any less beneficial in 1 location versus another. This study identifies an important metric for analyzing donation rates at the national level—age-stratified donor groups—which provide baskets of donors to reconsider. Although similar donation rates can be seen in different countries, their age-adjusted donation rates can vary widely. This nuanced analysis is important for stakeholders and citizens to incorporate into their quest for improved organ donation. In the United States, specifically, potential for older donors to provide greater access to organ transplantation is a clear target. The present-day push for deceased donor organs via normothermic regional perfusion and other new transplant access strategies will require on-going investigation and analysis with discrete data and even more judicious metrics to shine light toward more optimized systems of deceased donation.