Global transplantation: Lessons from organ transplantation organizations worldwide

Abstract

Although national transplant organizations share common visions and goals, the creation of a unified global organization remains impractical. Differences in ethnicity, culture, religion, and education shape local practices and infrastructure, making the establishment of a single global entity unfeasible. Even with these social disparities aside, logistical factors such as time and distance between organ procurement and transplantation sites pose significant challenges. While technological advancements have extended organ preservation times, they have yet to support the demands of transcontinental transplantations effectively. This review presents a comparative analysis of the structures, operational frameworks, policies, and legislation governing various transplant organizations around the world. Key differences pertain to the administration of these organizations, trends in organ donation, and organ allocation policies, which reflect the financial, cultural, and religious diversity across different regions. While a global transplant organization may be out of reach, agreeing on best practices for the benefit of patients is essential.

Key Words: Organ transplantation; National transplant organizations; Organ donation; Global transplantation; Transplant systems

Core Tip: Organ transplantation activities are managed by specific organizations in various countries, each with unique structures, protocols, and practices. These include differences in listing criteria, prioritization on waiting lists, donor preferences (living vs deceased), and organ distribution frameworks. This review explores these variations, particularly focusing on kidney and liver transplants, and highlights the lessons learned from this diverse organizational landscape that can promote future improvements.

INTRODUCTION

The concept of organ transplantation has long captivated human imagination. Early myths, artwork, and accounts of deities or healers performing transplants are found in ancient civilizations known for their contributions to modern medicine, such as the Greeks, Chinese, Indians, and Egyptians[1,2]. Given this history, it is unsurprising that technological advancements and globalization have played a key role in the rapid progress of organ transplantation in modern times[3,4].

Since the first successful kidney transplant in 1954, using an identical twin as the donor, Murray and his team turned a mythological aspiration into reality, forever changing the landscape of modern medicine[5,6]. Organ transplantation has since been established as a vital treatment that can significantly prolong survival and improve the quality of life for patients with end-stage organ failure. However, successful transplantation requires strict adherence to well-defined conditions, supported by structured programs providing administrative and legislative guidance[7,8].

Organ failure is a life-threatening condition characterized by the progressive or acute loss of an organ’s function. This can lead to organ insufficiency, poor prognosis, and the need for life-saving interventions such as dialysis[9,10]. For many vital organs, transplantation-whether from a deceased or living donor-is the only viable solution to restore function and prevent premature death[11]. In 2022 alone, 157553 organ transplants were performed worldwide[12,13].

Table 1 lists the countries active in the field of organ transplantation. Despite the widespread use of transplantation procedures, significant differences remain in the number of transplants performed and donor types across regions. The Americas lead with 62153 organ transplants, followed by Europe and the Western Pacific with 40337 and 29014 transplants, respectively[12]. Africa lags significantly, with only 286 transplants recorded in 2022, highlighting its considerable challenges and underdevelopment in this field[12]. Of the organs transplanted globally, 108818 came from deceased donors, which is the preferred source in most countries[12,13]. Notably, Africa reported no deceased organ donations in 2022, except in South Africa, the only country in the region with policies allowing deceased donor transplants. Table 2 summarizes this data by continent, as reported by the Global Observatory on Donation and Transplantation (GODT).

Table 1 Countries performing organ transplants by continent.

Region	Country	Ref.
North and Central America	United States, Canada, Mexico, Guatemala, Dominican Republic, Cuba, Honduras, Nicaragua, El Salvador, Costa Rica, Panama, Jamaica, Trinidad and Tobago, Barbados	[12,13]
South America	Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Paraguay, Peru, and Uruguay
Europe	The 27 member states of the European Union, United Kingdom, Ukraine, Belarus, Switzerland, Bosnia and Herzegovina, North Macedonia, Moldova, Albania, Norway, Iceland, and Turkey
Asia	Armenia, Azerbaijan, Afghanistan, Bangladesh, China, Georgia, India, Indonesia, Iran, Iraq, Israel, Japan, Jordan, Kazakhstan, Kuwait, Lebanon, Malaysia, Mongolia, Oman, Pakistan, Philippines, Qatar, Saudi Arabia, Singapore, South Korea, Syria, Sri Lanka, Taiwan, Thailand, United Arab Emirates, and Vietnam
Oceania	Australia and New Zealand
Africa	South Africa, Sudan, Ivory Coast, Ghana, Kenya, Egypt, Ethiopia, Nigeria, Namibia, Tanzania, and Mauritius

Table 2 Annual (2022) overview of transplantation activity by region.

Region	Deceased donors	Living donors	Total number of organ transplants	Ref.
Americas	20946	10527	62180	[12]
Europe	11649	9816	40337
Western Pacific	6702	8535	29014
South-East Asia	1244	13824	17214
Eastern Mediterranean	1251	5674	8490
Africa	-	286	286

These disparities are closely linked to variations in the availability of well-structured transplant programs, education on organ donation, religious beliefs, funding, and public trust in healthcare systems. Robust transplant programs are well established in North America and Europe, accounting for their higher transplant numbers. Meanwhile, Asia and especially Africa, are hindered by limited access to transplant services, insufficient funding, and scepticism toward healthcare[14,15].

Modern transplant programs rely on government or local support and involve regulatory frameworks, infrastructure, operational processes for organ allocation and distribution, research, and training opportunities[16]. While most National Transplant Organizations (NTOs) share common goals, differences in their operational frameworks stem from social, religious, and economic factors unique to each country, making the formation of a "Global Transplant Organization" infeasible.

This review highlights these differences and the lessons they offer. Although the focus is on specific countries (United States, United Kingdom, Spain, Croatia, Eurotransplant, Scandiatransplant, India, Iran, and China), the review also includes insights from other nations. While the creation of a global transplant organization may be unlikely, the continuous pursuit of growth and improvement will enable NTOs to maintain shared visions and advance future practices.

Relevant academic literature was sourced from PubMed/MEDLINE, Scopus, and Embase databases using the following keywords: "Transplant Programs", "Global Transplantation", "Allocation Policies", "Structure of Transplant Organizations", and "Organ Donation Practices". Policy documents, white papers, government reports, and data on transplant organizations and healthcare expenditures were retrieved from Google, National Transplant Organization (NTO) websites, government portals, Eurostat, the GODT, and the International Registry in Organ Donation and Transplantation.

Initial screening excluded papers with irrelevant titles, non-English language documents, and case reports. Authors then reviewed the abstracts and full texts to determine eligibility. Ultimately, only studies focused on national transplant programs, NTOs, organ allocation and donation policies, and national and international legal frameworks for transplantation were included.

NTOS: STRUCTURAL ELEMENTS AND PRINCIPLES

Organizational framework

Organ donation and transplantation are sensitive topics that require detailed organization, management, and oversight for success. Factors such as an aging population, increased demand for organs, controversies around the allocation process, and the need for public trust necessitated the formation of formal NTOs[17,18].

In the United States, these concerns were recognized early by Congress, leading to the enactment of the National Organ Transplant Act (NOTA) in 1984, which laid the foundation for modern transplantation[19,20]. NOTA mandated the creation of the Organ Procurement and Transplantation Network (OPTN) and the Scientific Registry of Transplant Recipients (SRTR). It also stipulated that non-profit private organizations must operate these networks under federal contracts with the Health Resources and Services Administration (HRSA), a branch of the United States Department of Health and Human Services[20,21]. The requirement for a private organization to manage OPTN and SRTR was based on the understanding that medical experts are better suited to legislate on these matters than politicians[21-23]. Alongside NOTA, the HRSA's "Final Rule" clarified the structure and framework of the OPTN, emphasizing the need for equity and transparency in organ distribution[23,24]. The United Network for Organ Sharing (UNOS) was appointed as the contractor for the OPTN and is responsible for maintaining the waiting list, reviewing policies and laws related to transplantation, and managing 56 procurement teams and over 250 transplant centers[25].

In the United Kingdom, the National Health Service Blood and Transplant (NHSBT) oversees all deceased organ donations and transplantations[26]. Serving approximately 66.6 million people, the NHSBT supervises 12 regional organ donation teams and works with eight advisory groups that facilitate dialogue between clinicians, scientists, patients, and NHSBT representatives[27]. For living donation (LD), the Human Tissue Authority ensures that legal and ethical standards are met to protect the interests of both donors and recipients[28,29]. The United Kingdom's significant success in organ transplantation can be attributed to the implementation of the 2008 Organ Donation Taskforce recommendations, which called for structural reforms, new policies on donation and allocation, and clearer leadership roles to support transplant centers[30]. This overhaul led to a near doubling of deceased donation (DD), from 13 per million people (PMP) to 24.2 PMP over a decade[31].

Each NTO operates within the framework of its respective healthcare system, which varies by country. For example, Croatia, with a population of only 3.86 million, has a unique transplant program overseen by the Ministry of Health and led by a National Transplant Coordinator[32]. This streamlined system has made Croatia a leader in transplantation, boasting the highest rate of DD after brain death (DBD) in Europe, at 40.24 PMP in 2018[33].

Spain is another world leader in organ donation, with 47 donors PMP (2022)[34,35]. The success of Spain's NTO, Organización Nacional de Trasplantes (ONT), is attributed to its three-tiered structure that operates at national, regional, and local levels[36]. ONT works closely with regional offices in each of Spain’s 17 autonomous regions to create policies, review guidelines, and set strategic plans[37,38]. Spain’s world-leading DD rate of 46.03 PMP and its total transplantation rate of 115.31 PMP, second only to the United States's 130.65 PMP, highlight the efficiency of this system[12,13].

NTOs from smaller countries often collaborate with others to fill gaps in donation capacity. These partnerships include bilateral agreements and broader alliances like Eurotransplant and Scandiatransplant[39-41]. Eurotransplant serves eight countries-Austria, Belgium, Croatia, Germany, Hungary, the Netherlands, Luxembourg, and Slovenia-covering 136 million people[40]. Similarly, Scandiatransplant serves six countries, including Denmark, Finland, Iceland, Norway, Sweden, and Estonia, covering 28.9 million people[41]. Table 3 exhibits data on donation and transplantation for both Eurotransplant and Scandiatransplant. In 2023, 2079 organ donors were utilized within the Eurotransplant, of which all were deceased donors, leading to a total of 6771 and 44 transplanted organs within the borders of Eurotransplant and non-member European countries, respectively. Scandiatransplant, on the other hand, recorded 690 organ donors, of which 12 were living donors, and 2316 transplanted organs, of which 2305 were among member states.

Table 3 Annual (2023) overview of Eurotransplant and Scandiatransplant.

	Year	Number of member countries	Organ donors	Deceased donors	Living donors	Total Tx	Tx within the alliance	Organs exchanged	Ref.
Eurotransplant	2023	8	2079	2079	-	6815	6771	1471 within Eurotransplant and 44 to non-member, European countries	[40]
Scandiatransplant	2023	6	690	678	12	2316	2305	546 within Scandiatransplant and 11 to non-member, European countries	[41]

Tx: Transplantations.

Significant progress has also been made in Asia[42,43]. For instance, India’s National Organ and Tissue Transplant Organization oversees organ donation activities in collaboration with regional and state programs[44]. However, India faces challenges such as illegal organ trafficking and a shortage of donors[45,46]. China, after years of relying on organs from deceased prisoners, has developed a robust transplantation system supervised by the National Organ Donation and Transplantation Committee[47,48]. Despite these improvements, cultural and religious beliefs continue to limit organ donation in many Asian countries[49].

Funding and expenditure

Funding and healthcare expenditure are critical factors affecting the progress of organ transplantation, both in terms of quantity and quality[50,51]. Higher hospital budgets, supported by government funding, are linked to increased numbers of both living and deceased donors[52-54]. Financial compensation and coverage are particularly important for living donors, as the costs associated with donation, such as pre-surgical evaluations, transportation, loss of income, and long-term health risks, can be prohibitively high[54]. In some cases, these expenses can reach up to $49192, discouraging potential donors[54].

The correlation between healthcare expenditure and transplantation rates is evident, with Western countries like the United States, the United Kingdom, and France, which spend 17.30%, 11.30%, and 12.30% of their gross domestic product on healthcare, respectively, reporting higher donor and transplantation rates. However, countries like Spain, Portugal, and Croatia demonstrate that financial constraints do not necessarily inhibit progress. Good governance and effective planning can increase public trust in healthcare and improve donation and transplantation rates[55-57].

For example, Japan, which spends more on healthcare than other Asian countries, still lags behind South Korea in transplantation rates despite higher overall healthcare expenditure. This suggests that other factors, such as cultural and religious beliefs, play a significant role in transplantation activities[58].

Supplementary Table 1 presents data regarding trends in organ donation, and transplantation and healthcare expenditures in 2022 for various countries worldwide, constituting a representative sample of the current transplantation landscape.

Lessons

A robust operational and legislative framework is essential for the sustainability and success of a national transplant program. Countries seeking to reform their transplant systems should look to Spain's ONT as a model. Its global success-demonstrated by high transplantation and DD rates, alongside favorable public trust and attitudes towards the system, which have remained consistently above the European average for over three decades-offers many valuable lessons.

One of the key components of Spain’s success is its multilayered structure. Other countries that have adopted similar frameworks have also seen continuous improvements. A central authority, supervised by the government and responsible for overall management and data analysis, along with clearly defined strategic plans and goals, plays a pivotal role in establishing a solid organization capable of meeting a country’s demands and expectations. This central authority must also work to build public trust by adopting transparent legislation, implementing sound financial policies, and collaborating with the media. Localized committees, representing smaller administrative offices in each region, serve as the link between the government and local transplant centers, providing essential coordination. At the local level, transplant centers and hospitals are responsible for organ procurement, transplantation procedures, and conducting audits and quality assessments to identify and address obstacles and challenges.

However, NTOs must adapt to the unique characteristics of the populations that they serve, promoting research and education on organ donation and transplantation that is tailored to local needs. While there is a wide gap in healthcare expenditure across different countries, Spain has shown that financial constraints are not an insurmountable obstacle. In contrast, Japan and South Korea illustrate that higher spending does not necessarily correlate with higher donation and transplantation rates.

Though the field of medicine may occasionally rely on extraordinary occurrences, establishing a strong transplant organization should be based on long-term planning and governmental commitment, rather than chance. Despite the differences in structural frameworks and funding, countries aspiring to improve in this area should not be deterred by the inability to create a single global transplant organization. Instead, they should draw inspiration from successful programs that have achieved notable results.

RECIPIENTS AND ALLOCATION

Liver

Liver transplantation (LT) is one of the most significant medical advances of the 20^th century, recognized as the definitive treatment for patients with end-stage liver disease (ESLD)[59]. Today, LT is the second most frequently performed solid organ transplantation, with a global rate of 6.25 PMP in 2022. This aligns with the high prevalence and mortality of ESLD, which accounts for 4% of global deaths[60].

Indications

Historically, the primary indications for LT were cirrhosis and hepatocellular carcinoma (HCC), often resulting from chronic viral hepatitis [hepatitis B virus (HBV) and hepatitis C virus (HCV)], followed by alcoholic liver disease (ALD). However, recent trends show a shift in the leading causes of LT[60-62]. With the advent of vaccines and direct-acting antivirals against HCV, ALD and non-alcoholic fatty liver disease have emerged as the top causes of cirrhosis-related LT, accounting for 60% and 32.4% of cases globally, respectively[63-66]. Nonetheless, HBV and HCV remain major contributors to cirrhosis and HCC in various regions, particularly in countries like China (87 million affected), Nigeria (20 million), and India (40 million)[60-64].

Prioritization and distribution

Medical and surgical advancements, including immunosuppressive drugs, minimally invasive procedures, and genetically modified organs, have expanded the range of conditions treatable by LT[67,68]. Despite over 27000 procedures performed globally each year, with 1-year survival rates reaching 84% and 10-year survival at 61%, the demand for liver transplants still far exceeds supply[66,69]. Consequently, the allocation of this scarce resource remains a significant challenge and subject of debate for NTOs.

Prior to 1997, liver graft allocation in the United States was determined based solely on hospitalization status and waiting time, a system vulnerable to manipulation. In response, the UNOS revised the policy, introducing a four-tier status system based on patient severity. Status 1 patients (those with acute liver failure) were given priority, followed by statuses 2A, 2B, and C. The Child-Turcott-Pugh (CTP) score, which evaluates factors such as hepatic encephalopathy, ascites, bilirubin levels, and prothrombin time, was employed to classify patients in the lower statuses[70,71].

The model for ESLD (MESLD) score, designed initially to predict survival in patients undergoing transjugular intrahepatic portosystemic shunt, has since proven to be a more accurate predictor of 3-month mortality in ESLD patients[72]. The MESLD score, based on international normalized ratio, serum bilirubin, and serum creatinine, objectively ranges from 6 to 40, prioritizing the sickest patients[73,74]. In 2002, UNOS adopted a MESLD-based prioritization system, a model that many countries have since followed[73]. Adjustments, such as the inclusion of sodium levels and exception points for HCC, have been made over time to further refine the system[75].

Other countries have developed their own allocation models. The United Kingdom employs the Total Benefit Score, which considers recipient and donor criteria, while France uses the Liver Score, focusing on indication for transplantation, waiting time, and MESLD score[76,77]. In Scandinavia, where transplantation volumes are lower, waiting time remains the primary criterion[78,79].

In Asia, transplant allocation models vary widely. Iran, for instance, lacks a national transplant registry, with local hospitals managing waiting lists and prioritization[79]. In contrast, Japan and China have implemented systems based on MESLD, CTP, and waiting time[77].

Kidneys

In 2022, 102149 kidney transplants were performed globally, making kidneys the most frequently transplanted organ, with donations from both deceased and living donors[12,13]. An estimated 4 million people worldwide undergo renal replacement therapy, with hemodialysis being the dominant treatment method, accounting for 69% of cases[80-82]. Although hemodialysis sustains life for patients with acute kidney injury and chronic end-stage kidney disease, kidney transplantation (KT) offers superior outcomes, including improved quality of life, reduced mortality, and better cost-effectiveness[83-87].

Indications

Kidney disease is a global health concern, affecting approximately 850 million people, which accounts for more than 10% of the global population[88,89]. Recent reports indicate that the highest prevalence is in Asia and the United States, with rates ranging from 7.0% to 34.3% in Asia and 14.9% in the United States, followed by Eastern Europe at 12.8%[90,91].

Current kidney disease: Improving Global Outcomes guidelines recommend that patients with a glomerular filtration rate (GFR) of less than 15 mL/min per 1.73 m² (G5) should be considered eligible for KT. Preemptive transplantation (PEKT) should also be considered for adults with a GFR of 15–20 mL/min per 1.73 m² or a risk of requiring kidney replacement therapy greater than 40% within two years. Studies show that PEKT leads to better patient outcomes, including lower mortality and morbidity, and improved graft survival compared to non-PEKT[92-94]. The leading causes of end-stage kidney disease are diabetes, hypertension, and glomerulonephritis[90].

Prioritization and distribution

The critical shortage of available kidneys necessitates an effective allocation policy to ensure fair access to transplantation and improved post-surgical outcomes. Outside Asia, most kidney transplants come from deceased donors, and therefore, allocation policies must ensure equal opportunities for recipients while maintaining transparency and cost-effectiveness[12].

In the United States, it took over two decades to reform the Kidney Allocation System (KAS)[95]. Previously, waiting time was the primary criterion, with less emphasis on factors such as immunization levels, human leukocyte antigen (HLA) match, and blood type[96]. This led to significant disparities, particularly for ethnic minorities who may not have been promptly listed[97]. The lack of assessment for graft survival also contributed to mismatched transplants, where less durable kidneys were allocated to patients with longer life expectancies, resulting in poor post-transplant outcomes[98]. To address these issues, the KAS was introduced in 2014.

KAS incorporates biological factors into the matching criteria and better accounts for waiting time[96]. It uses the Kidney Donor Profile Index, which is based on ten donor characteristics, including biological, demographic, and biochemical parameters, to estimate the longevity of the graft[96]. Similarly, the estimated post-transplant survival score prioritizes patients with the highest likelihood of long-term survival[99,100]. In 2021, KAS was further updated, replacing donor service area boundaries with a 250-nautical-mile radius to create a more equitable distribution system[101].

In the United Kingdom, a tier-based scheme introduced in 2006 aimed to increase fairness for ethnic minorities and highly sensitized patients by grouping recipients into five categories based on age and HLA match[102]. However, challenges persisted, including longer wait times for sensitized patients and a mismatch between graft durability and recipient longevity[103]. A two-tier system was introduced in 2019, categorizing hard-to-match patients or those waiting more than seven years into "Tier A", and incorporating a longevity-matching element[104].

In France, the Unified Allocation Score system adjusts matching criteria based on recipient age, aiming for minimal donor-recipient age differences and optimal HLA matches for younger patients[105]. Spain employs virtual crossmatching to increase the chances of highly sensitized patients receiving a graft. Eurotransplant considers urgency and expected outcomes during the allocation process, while ensuring a balance in organ exchanges among member states[40,106]. In Scandiatransplant, patients with rare HLA types and highly sensitized individuals (panel reactive activity > 80%) are prioritized to reduce waiting time and improve graft survival[41].

Asia, despite its technological advancements, faces significant challenges in KT. Mistrust in public healthcare, cultural and religious concerns, and a lack of education about the benefits of transplantation contribute to low rates of deceased kidney donation. For example, China has a donation rate of 10.44 PMP, Japan 14.53 PMP, and South Korea 39.96 PMP, compared to Spain’s 77.68 PMP and the United States’ 82.78 PMP[12,42,107].

Different countries in Asia adopt varying allocation systems based on their needs. India prioritizes former living donors and relatives of deceased donors in its scoring system, while Japan, with a heavy reliance on living donors, often resorts to ABO-incompatible transplantations to overcome its limited donor pool[108,109]. Iran's compensated living donor program remains a controversial topic, as it involves financial incentives for organ donors, raising ethical concerns about whether such practices represent altruism or organ trafficking[110-112].

Lessons

The establishment of international organ exchange organizations, such as Eurotransplant and Scandiatransplant, has proven beneficial, increasing donor pools and improving transplant outcomes. These alliances foster international collaboration and strengthen global strategies in organ transplantation. While differences in allocation policies and cultural attitudes pose challenges to creating a single global transplant system, countries can still learn from successful programs around the world.

A unified global approach to preventing organ failure could reduce the demand for transplants. NTOs and international committees should prioritize reducing alcohol consumption, promoting healthy diets, and educating the public about diseases such as diabetes and hypertension, which are major contributors to organ failure. Prevention campaigns aimed at addressing these risk factors can help reduce the overall demand for transplants.

Additionally, specialized teams could be created to identify patients eligible for preemptive KT, which would improve patient quality of life and reduce healthcare costs. Countries struggling to reform their transplant programs should be provided with financial and technical support through international collaborations.

ORGAN DONATION AND DONORS

Legislation is critical in ensuring ethical practices in organ transplantation, fair allocation of organs, and the safety of both donors and recipients. Key regulations include guidelines on donation types (living or deceased), criteria for determining brain or circulatory death (DCD), and systems for organ donation (opt-in vs opt-out). A robust legal framework helps build public trust, encourages donation, and improves patient outcomes[113].

Organ donation occurs in two primary forms: LD and DD[114]. LD involves a healthy person donating an organ (e.g., a kidney or part of the liver) to a recipient. Donations can be directed to a specific individual or non-directed, where the organ is offered to an unknown recipient. In most countries, LD is viewed as a purely altruistic act, and the commercialization of organs is strictly prohibited by law and international consensus[115]. However, in Iran, the government supports compensated LD, which has led to significant controversy[111,116]. While this program has reduced waiting times for kidney transplants, critics argue that it contradicts the principles outlined in the Declaration of Istanbul, which condemns organ trafficking[115,116].

DD occurs after an individual is declared dead, either through DBD or DCD [117]. While DBD remains the primary source of organs for transplantation, advances in organ preservation have increased the use of DCD donors[118]. Cultural, religious, and educational factors significantly influence donation rates across different countries. For instance, some religious groups, such as Buddhists, Confucianists, and certain Jewish and Islamic communities, hold beliefs that discourage organ donation[119-122]. These views contribute to lower deceased donor rates in countries like China, Japan, India, and Pakistan[123-125].

In contrast, Western countries, where DD is more common, have well-established donation systems[126,127]. The use of DCD donors has grown in recent years due to improved preservation techniques, contributing significantly to the overall number of transplants in countries like the United States, Belgium, the Netherlands, and Spain[54,128,129]. However, some countries, such as Greece, Finland, and Germany, still have low rates of DCD donations[130-132].

In 2022, Spain had a DCD donation rate of 22.10 PMP, the United States 14.27 PMP, Belgium 13 PMP, and the Netherlands 10.10 PMP, while Finland, Greece, and Germany reported negligible rates[12,13].

Donation after death: Ethical considerations and policy implications

Donation after death, particularly donation after DCD, presents specific ethical considerations that must be clearly defined within the legal framework of each transplant program[133,134]. Ethical issues related to DCD donation include respect for the patient's autonomy, their right to refuse any potential life-sustaining treatment, and their decision on whether or not to become an organ donor. Additional ethical challenges encompass avoiding conflicts of interest between end-of-life care providers, physicians declaring death, and procurement teams. Other considerations include the extent to which recipients need to be informed about the donor's medical history and circumstances of death, as well as the appropriate timing for approaching families and initiating evaluations to determine organ donor eligibility[133,134]. Efforts to maximize both donation after DBD and DCD donations require complex, multidisciplinary collaborations among healthcare professionals, organ donation coordinators, and intensive care unit doctors[9].

Another classification of organ donation is based on the presumption of the donor's consent, categorized into two policies: Opt-in and opt-out. These policies apply solely to DD[135]. The opt-in system requires individuals to actively express their willingness to donate their organs after death and register in a national organ donor registry. In some countries, like South Korea, individuals must indicate their consent when obtaining their driver's license from local authorities[135,136]. In the United States, consent can be completed online[137].

Conversely, in an opt-out transplant program, all individuals are automatically considered potential organ donors unless they explicitly opt out. The effectiveness of donation policies is directly proportional to the capacity of a transplant program[37,138]. Spain, Portugal, and the United Kingdom have adopted an opt-out policy, which suggests that this legislation has contributed significantly to their success (Supplementary Table 1).

Lessons

Clear policies are essential for building public trust, ensuring equitable access, and maintaining safe practices in transplantation. Significant differences exist among countries regarding the expansion of the donor pool and the preference for deceased versus LD. These differences reflect regional backgrounds, social beliefs, and traditions. Cultural, educational, and religious factors often play a more substantial role in these disparities than financial parameters. Populations with inadequate education on organ donation and transplantation, or those from specific religious backgrounds, often exhibit lower donation and transplantation rates. Addressing these factors is crucial when exploring solutions to improve donation rates.

As the demand for organ transplantation continues to grow, decisive strategies are necessary. These include promoting transplant education and awareness, training young physicians, partnering with international transplant pioneers, seeking financial support from other countries for cooperation, and reevaluating current transplant legislation in collaboration with religious leaders.

DISCUSSION

Organ transplantation is a remarkable achievement of modern medicine practiced worldwide[3,4]. In 2022, a total of 108818 organs were transplanted globally, with the majority performed in the United States and Europe (62153 and 40337 organs, respectively) and the fewest in Africa (268 transplants) (Table 2). Despite the increasing demand for organ transplants due to an aging population and rising non-communicable diseases, a unified global transplant organization remains an unrealized vision.

In many countries, while NTOs may share similar ethics and objectives, significant disparities persist. These differences are evident in the structural and legislative frameworks, funding, and operational principles of transplantation systems. Socioeconomic, religious, and cultural factors often drive these disparities. As no universal guidelines or consensus for establishing NTOs exist, each country adopts a model tailored to its specific context. For example, in the United States, the OPTN is managed by the private non-profit organization UNOS under a contract from the HRSA[23-25]. In contrast, other countries' NTOs are either directly or indirectly supervised by their governments[26,35-37]. Spain's three-tiered model is particularly noteworthy, demonstrating success with leading donation and transplantation rates of 47 and 115.31 PMP, respectively, despite lower spending compared to other countries (Supplementary Table 1).

Organ shortage remains a well-documented issue, with demand far exceeding donor supply[69,108]. Efforts to address this problem include revising death determination criteria, amending legislation on organ donation types and policies, and adjusting allocation policies for greater equity and transparency[77,113]. Providing a clear legal framework is vital for building public trust and confidence in organ donation[113]. This is especially important in diverse regions like Asia, where certain traditions and social and religious beliefs hinder organ donation, particularly DD[121]. Supplementary Table 1 highlights the lower rates of DD in Asian countries compared to other regions. In Europe, Central European and Scandinavian countries have addressed graft shortages by forming international alliances, such as Eurotransplant and Scandiatransplant[40,41]. These alliances facilitate the exchange of unmatched organs, policy reforms, and discussions on challenges and future prospects.

Limitations

This review offers a comprehensive overview of national transplant programs across various countries with diverse socioeconomic, religious, and cultural backgrounds. However, several limitations exist. Although many countries perform transplant procedures, this study focuses primarily on a select few, namely, the United States, United Kingdom, Spain, Croatia, Eurotransplant and Scandiatransplant member states, India, China, and Iran. Information on other countries, such as Portugal, France, Japan, and South Korea, is included but to a lesser extent due to length constraints. Publicly available and up-to-date data are scarce for many African states, and official transplant and donation websites are lacking in numerous countries, including those in South America. Additionally, only English-language literature was considered, potentially omitting valuable information from official sources and publications in other languages.

Future directions

The need for further advancements in transplantation is clear, as is the necessity for continued research. Recognizing the limitations of the current study, future work would benefit from interviews and direct discussions with transplant officials, representatives, and physicians from around the world, particularly from regions with limited available data. These discussions would allow experts to share key aspects of their programs, as well as their visions and challenges. Additionally, employing questionnaires and a more flexible study design that includes material in languages other than English could provide a more comprehensive understanding of the topic and improve the interpretation of valuable data.

CONCLUSION

Various factors, including education, finances, religion, and social influences, affect organ transplant practices and create gaps and disparities among countries. These factors reflect the organizational and legislative frameworks, ethics, and operational patterns of each national transplant organization, making the establishment of a unified global organization challenging. Nevertheless, widely applicable practices such as ongoing education, public awareness campaigns, regular evaluation of policies and guidelines, and international collaborations like Eurotransplant and Scandiatransplant should be seriously considered by all countries aiming to advance in the field.