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Clinical and Translational Research

Motivations, Outcomes, and Characteristics of Unspecified (Nondirected Altruistic) Kidney Donors in the United Kingdom

Maple, Hannah1; Chilcot, Joseph2; Burnapp, Lisa1,3; Gibbs, Paul4; Santhouse, Alastair5; Norton, Sam2; Weinman, John2; Mamode, Nizam1,6

Author Information
doi: 10.1097/TP.0000000000000340


Living kidney donation now accounts for more than one in three of all kidney transplants performed in the United Kingdom. The donation of a kidney from a living person to a stranger (someone with whom they have no genetic or emotional relationship) was legalized in 2006 and has led to more than 200 donations across the United Kingdom. Many different terms have been used for these donors including altruistic, anonymous, nondirected, “Good Samaritan,” and unspecified. The Ethical, Legal, and Psychosocial Aspects of Transplantation section of the European Society for Organ Transplantation has agreed on the term “unspecified kidney donation” (UKD) (1), and we use that nomenclature here.

Unspecified kidney donation is growing in popularity (Fig. 1), and after an initial slow start by some, most U.K. transplant centers are now participating (22 out of 23 centers) (Fig. 2). For some, the concept of UKD remains uncomfortable (2) principally because of a presumption that a request to donate is a manifestation of an underlying psychopathology (3) or a lack of understanding by the donor of the risks involved. Historically, similar concerns were raised about specified kidney donation (SKD—where people donate to a recipient they know) when these programs were in their infancy (4). There are also concerns about subsequent regret after donation and the lack of contact or emotional involvement between donor and recipient, which may have negative consequences (5).

Total number of unspecified kidney donations taking place per year in the United Kingdom (data to 31st December 2013).
Range in the number of unspecified kidney donations performed in total per U.K. transplant center (data to 31st December 2013).

Globally, UKD is legal in a minority of countries with the majority of donations taking place in the United Kingdom, the Netherlands, and the United States. The U.K. scheme is administered by National Health Service Blood and Transplant (NHSBT) and legal authorization is granted from the Human Tissue Authority. Potential unspecified kidney donors (UKDs) undergo the same evaluation as specified kidney donors (SKDs) with an additional mental health assessment which, although no longer legally mandatory, remains the agreed clinical standard in the United Kingdom.

There are two key questions related to UKD that remain unanswered and which have major implications for practice. First, what characteristics and motivations result in someone becoming a UKD? Second, is the practice safe in terms of psychosocial and physical outcomes and do donors experience regret after donating? Because the U.K. scheme is centrally co-ordinated and requires mandatory registration and follow up of all donors, we are in the unique position of being able to study all UKDs who have donated and compare motivations and outcomes with a group of SKDs.

The aims of this study were to assess donor motivations, both psychosocial and physical outcomes after unspecified kidney donation, to determine the prevalence of donors who regret donation and the extent of contact between unspecified kidney donors and their recipients.



One hundred ninety responses were received from the 296 questionnaires distributed (64.2% total response rate). There was a significant difference between the groups in the number of responses received (110 UKDs [74.3%] vs. 80 SKDs [54.1%]; P<0.001). Table 1 displays the demographic data for both groups. The UKD group were on average 10 years older and predominantly of white ethnicity, were less likely to be currently working (33.9% retired), have children, or have current dependents. The UKD group showed a higher incidence of previous surgery and, despite no difference in mental health history, showed more commonly experienced episodes of low mood lasting more than 2 weeks. Geographical data were limited but demonstrated that only a small number of UKDs donated away from their nearest transplant center (7 vs. 80 donors; P<0.001). In the SKD group, there was no significant difference in sex between responders and nonresponders; however, nonresponders were found to be significantly younger (38.2 years vs. 44.0 years; P=0.001). Sex and age data were not available for nonresponders in the UKD group.

Demographic details

Motivations and Donor Characteristics

Most UKDs were made aware of altruistic kidney donation through the media (64 donors [58.2%]) or through researching other forms of donation (10 donors [9.1%]). Other modes included knowing someone with renal failure or a transplant (12.8%) and knowing someone who had been a living kidney donor (UKDs or SKDs) (5.5%). A minority were made aware by family, friends, or a religious organization (3.6%), had heard about UKD through work (5.5%), or considered the idea of their own accord (2.7%). The most common reasons for donating were “I thought my donation would make little difference to my own life but a huge difference to someone else’s” (30 UKDs [27.3%]) and “I wanted to help someone” (13 UKDs [11.8%]) (Table S1,SDC,

There was no significant difference in personality traits between the two groups across each of the personality domains measured (extraversion [P=0.586], agreeableness [P=0.719], conscientiousness [P=0.719], emotional stability [P=0.418], and openness [P=0.948]). No personality trait was identified as being more common in either group. The UKDs were found to be more altruistic in other areas when compared with SKDs across five separate markers of altruism: blood donation (77.3% vs. 45.0%; P<0.001), bone marrow registration (30.3% vs. 7.5%; P=0.001), organ donor registration (94.5% vs. 58.8%; P<0.001), participation in volunteer work (56.4% vs. 32.5%; P=0.001), and monetary donations to charity (82.7% vs. 65.0%; P=0.005).

Postoperative Psychosocial Outcomes

The UKD group donated more recently (1.3 years vs. 2.6 years; P<0.001) which reflects the increase in numbers of people becoming UKDs in the past 12 months. Table 2 contains both unadjusted and adjusted difference scores for each of the psychosocial measures used. Adjusted models controlled for age at donation, time since donation, sex, relationship status, children, ethnicity, education, employment status, and previous low mood lasting more than 2 weeks. Across the psychological measures used, no significant difference was demonstrated between the two groups. A significant difference was demonstrated in the perceived level of social support and social comparison (i.e., where one sees oneself in relation to others), but this difference became insignificant in the adjusted model.

Psychosocial outcomes in UKD and SKD groups

Physical Outcomes

Due to many donors donating less than 12 months before the study, limited 12-month and 24-month clinical follow-up data were available. Objective physical outcome measures, such as blood pressure, estimated glomerular filtration rate, serum creatinine, and hemoglobin were not found to be statistically different between the groups when controlling for age, sex, and preoperative values. There was no significant difference in the rate of complications or the number of complications requiring further admissions to hospital (11 UKDs vs. 8 SKDs; P=0.956) or reoperation (3 UKDs vs. 6 SKDs; P=0.121). There was no significant difference in length of stay (UKDs 3.65 days vs. SKDs 3.95 days P>0.05). When comparing responders and nonresponders in the UKD sample, there was no difference in postoperative outcomes (blood results, blood pressure, rate of complications, and length of stay). Subjective markers of recovery demonstrated faster recovery in the UKD group, such as return to work (4–6 weeks vs. 6–12 weeks; P<0.001), return to driving (<4 weeks vs. 6–12 weeks; P<0.001), and return to feeling normal (6 weeks vs. 12 weeks; P=0.001). There was no significant difference in residual operative site pain (P=0.156) (Table 3).

Physical outcome measures

Regret and Attitudes

The donation-specific questions (Table S2, SDC, demonstrated that both groups equally felt that organ donation in general was a good thing (109 UKDs [99.1%] vs. 80 SKDs [100%]) and that they felt good about being a living kidney donor (106 UKDs (96.7%) vs. 76 SKDs (95%)). Neither group felt that donating had increased their self-esteem. The SKD group had received more praise (P=0.02), had higher perceived social support for their decision to donate (P<0.001), and considered their donation as a more significant life event (P=0.002). Current regret was low for both groups (4 UKDs vs. 6 SKDs; P=0.078), and there was no difference when anticipating regret in the future (6 UKD vs. 10 SKD; (P=0.052)).


Fifty-four (49.5%) of UKDs received a card or a letter after their donation, the majority within 3 months of donating (70.1%). Of those who did not receive a card, the majority ‘would have liked or maybe would have liked’ to receive one (87.3%). Seventy-one UKDs (65.1%) had found out what had happened to the recipient after their donation with two donors experiencing some regret at this knowledge (4.9%). Further contact was minimal (14 donors; 12.8%) with only two pairs meeting in person (1.8%). Neither donor regretted meeting their recipient.


This study is the largest study of unspecified donors that has ever been conducted, both in its sample size and the range of psychosocial outcome measures used. It is the only study that compares those who have donated a kidney entirely anonymously to a stranger with those who have donated a kidney to a loved one. It is also the only study that has attempted to capture data from a consecutive, nationwide sample of UKDs where every individual who has donated was invited to participate. The main findings of this study are that there is no significant difference in personality, psychosocial, or physical outcomes or regret between UKDs and SKDs. UKDs recover more quickly from surgery, are motivated by a desire to help others, and are more likely to engage in other forms of altruistic behavior. Communication from the recipient is welcomed; however, very few UKDs desire formal contact.

There is a broad literature related to UKD but very little clinical data. Most articles outline different UKD guidelines and practices (6–9); provide commentaries on donation, altruism, and the role of the psychiatrist (10–14); present the views of transplant physicians(15); and consider the role of UKDs in initiating living donor chains (16, 17). The ethical aspects and practicalities of UKD have also been discussed at length (18–20). Few clinical studies have been performed, all with sample sizes of less than 50 UKDs (21–28), and only one has used a comparison group of SKDs (28).

This study has demonstrated equivalent levels of stress, anxiety, distress, and depression between the two groups. This demonstrates that there is no negative psychological impact after UKD when compared to SKD. Similarly, levels of wellbeing, life satisfaction, self-esteem, and optimism were also equivalent. This demonstrates that there is no significant difference in how UKDs feel about their quality of life and toward themselves. As discussed previously, the body of evidence in support of UKD is limited. The five small studies that precede our work have suggested that both physical and psychosocial outcomes may be acceptable and comparable with SKDs, although it is impossible to draw definitive conclusions because of the small number of donors assessed and the small range of measures used.

The only study with a similar design to ours is the study by Rodrigue et al. (28). This study also demonstrated no difference between SKDs and a mixed sample of UKDs (which included those donating completely anonymously, as in our sample, and those donating to a named individual; so-called directed altruistic donation); however, the sample size of purely anonymous UKDs was small (19 donors), and only two validated questionnaires were used. Our study is able to provide the transplant community with the most convincing evidence to date that UKDs and SKDs have equivalent psychological outcomes after donation. All UKDs in this sample would have received a mental health assessment before donation, and although it is not possible to know how those who were screened out would have fared had they been allowed to donate, we can be reassured that those who have been allowed to donate do well postoperatively. What is perhaps more surprising is why the SKD group did not have superior results to the UKD group, as one may hypothesize that there should be an additional psychological benefit to SKDs from seeing their recipient well and further benefit from improvements in their own lives as a secondary positive outcome.

The UKD group showed a higher incidence of previous surgery, which may be accounted for by the increased age. Despite being 10 years older, the UKD group recovered significantly quicker across all markers of subjective recovery. This may provide additional insight into how highly motivated these donors are toward their operation and subsequent recovery or may reflect additional physical demands placed on recovering SKDs who may provide care for their recipient.

This study is limited by its retrospective design and regional SKD comparison group. The clinical history and outcomes were mostly self-reported and may be subject to bias. There may be some selection bias within the sample with fewer responses from those with negative experiences or those with poor psychosocial outcomes. In addition, it was also not possible to establish where (i.e., which transplant center) the UKDs nonresponders were from and their reasons for not wishing to participate. A further limitation is the size of the SKD comparison group which resulted in low statistical power to detect adverse outcomes, such as regret. A nationwide prospective study is needed to further evaluate some of these issues and should allow for a more in-depth analysis of the impact of donation by comparing preoperative and postoperative scores. Finally, this study investigated the largest cohort of available UKDs at the time, which encompassed the first 5 years in the history of the U.K. UKD programme. The speed with which the programme has expanded has moved UKD from exceptional to usual practice in a relatively short timeframe and therefore has created a steep learning curve for health care professionals. Although it is uncertain why the practice has been accepted so readily, we postulate that this may be because of the media interest and promotion by patient groups. The findings of this study are inevitably influenced by the change in approach to UKDs by the clinical community.

When looking to the future, UKD is becoming more popular in the United Kingdom. Completion of a mandatory mental health assessment has been removed by the Human Tissue Authority but currently remains the agreed clinical standard. This study has demonstrated that a mental health history does not prohibit UKD nor does it increase the likelihood of an adverse postoperative outcome. Our sample of UKDs would have all undergone a mental health assessment, some of whom may have found it to be the most concerning part of their workup (29). There are no data available regarding the sensitivity and specificity of these assessments or whether they can be safely removed, yet there are still large numbers of potential UKDs who are screened out for a variety of psychosocial reasons (30). Given the positive psychosocial outcomes reported from this study and the reliance on positive outcomes to further expand the programme, it may be prudent for mental health assessments to remain best practice until further evidence is available.

This article has demonstrated that UKDs have comparable physical and psychosocial outcomes to SKDs. There is little regret and very little contact between donors and recipients. These findings are encouraging and support continued and safe expansion of the U.K. programme with the expectation of favorable outcomes.



We performed a cross-sectional evaluation of psychosocial outcomes in a national sample of UKDs. This included all 148 UKDs who had donated in the United Kingdom since the scheme began in February 2007 until the study ended in November 2012. The UKDs were recruited through lists obtained from NHSBT. The UKD sample was compared with 148 SKDs recruited from Guy’s Hospital. Every SKD undergoing surgery at Guy’s Hospital between 2007 and July 2012 was considered for inclusion. Those SKDs who had not been followed up at Guy’s Hospital and those involved in other psychology research studies (40 patients involved in a prospective quantitative study running simultaneously) were excluded. A list of 298 donors remained which was then sorted by date of donation. Alternate names were then selected.

All donors were sent a questionnaire by post and were provided with an option to complete it on paper or online by means of a secure website. One postal reminder was sent after four weeks. The questionnaire consisted of three sections:

Section 1

Demographic questions (ethnicity, religious beliefs, highest level of education, current employment and relationship status, number of children, and number of dependents in their household). The UKD sample received additional purposely designed questions relating to their donation (including timing and location, awareness of the programme, and motivations). A list of reasons for donating was provided (Table S1, SDC,, and UKDs were asked to select which reasons were applicable before selecting a single most important reason.

Section 2

Twelve validated questionnaires investigating a range of psychosocial factors (Table 4). Validated abbreviated versions of questionnaires were used where possible to decrease responder burden.

Validated questionnaires

Section 3

Donation-specific questions. These were divided into medical history (including surgical procedures and mental health), alternative markers of altruism (including blood donation, bone marrow and organ donor registration, regular charitable donations and volunteer work), and postoperative recovery (complications, residual pain and return to driving, work and normal function). Both groups were asked ten questions about their feelings toward their donation (Table S2, SDC, and were provided with a five-point Likert scale (strongly disagree to strongly agree). The UKD group were asked additional questions related to recipient contact.

All new questions were tested for face and content validity on a separate sample of 20 SKDs and modified accordingly before being retested and finalized.

A retrospective evaluation of clinical outcomes at 12 and 24 months was also performed. Physical outcome data for all UKDs (including nonresponders) was cross-linked securely from NHSBT by the national organ donor number (blood pressure, estimated glomerular filtration rate, serum creatinine, and hemoglobin). An analysis of responders vs. nonresponders was performed focussing on length of stay, major complications, and the year of donation to determine whether those who had not responded experienced inferior physical outcomes. Physical outcome data for the SKD group was obtained from hospital records. Self-reported data were cross-checked with objective clinical data where possible.

National Health Service research ethics approval was obtained (09-H0804-31).

Statistical Analysis

Comparisons between UKD and SKD groups were evaluated using chi-square (Fisher’s exact test), Student’s t test, and analysis of variance models as appropriate. Unadjusted and adjusted mean differences between the donor groups for the psychological variables were calculated using multivariable linear regression analysis. To control for potential confounding effects, adjustment controlled for age at donation, time since donation, sex, relationship status, number of children, ethnicity (white vs. non-white), education (higher education vs. less than higher education), employment status, and previous low mood lasting more than 2 weeks. Both unadjusted and adjusted mean difference scores (standard errors) are presented. P values less than 0.05 were considered as significant. Presence of missing data for the variables in the analysis was low, ranging between 0 and 12 observations per variable (0% and 6.3%). Because the spread of missing data across variables meant omitting between 10 (5.3%) and 21 (11.1%) observations in the complete case analysis to calculate adjusted mean group differences, a multiple imputation analysis was conducted where missing data were imputed across 10 data sets using the chained equations approach (31). The results from the multiple imputation analysis are provided in the supporting information (Table S3, SDC, Because the proportion of missing data for individual variables was low, sensitivity analysis for a nonignorable missingness was not necessary. Statistical analysis was performed using SPSS (version 20; IBM, Armonk, NY) and Stata (version 12.1; StataCorp, College Station, TX).


The authors thank Patricia Swetman from Guy’s and St Thomas’ National Health Service Trust and the statistics and data services teams at NHSBT for their administrative support.


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          Living donor; Kidney transplantation; Altruistic kidney donation; Unspecified kidney donation

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