Solid-organ transplantation offers life-saving treatment to patients suffering from end-stage organ dysfunction. However, the growing number of patients on the waiting list largely outweighs the number of donors’ organs available, a persistent concern in transplantation medicine. In the United States, although more than 40,000 transplants were achieved in 2022, the waiting list still comprised more than 100,000 candidates in need of an organ (1). In Canada, where our team is based, in 2021 alone, more than 4,000 patients were on a waiting list to receive a transplant, and 38% of them ultimately died while waiting (2, 3). The COVID pandemic, beginning in March 2020, has also had a negative impact on transplant success. Indeed, in Canada the total number of solid organ transplants has dropped by 14% from 2019 to 2020 (2, 3).

Due to the scarcity of resources and complexity of the treatment regimen surrounding transplant, potential candidates usually undergo a thorough preoperative screening. This allows for a precise understanding of the patient's global health status to determine whether they are suitable candidates for transplantation. Amongst these variables, psychosocial factors are now widely recognized health determinants (4), which are associated with transplantation outcomes (5, 6). Even though the Centers for Medicare & Medicaid Services (CMS) demands that a psychosocial examination is done before transplant (7), there is no solid research data supporting this practice. Different guidelines also agree on the necessity of screening patients for psychosocial risk factors before transplantation and this is usually done by a psychiatrist, psychologist and/or a social worker working as a part of the transplant team (8, 9). However, while the medical evaluation of transplant candidates is well standardized across hospitals, the evaluation method for psychosocial risk factors differs greatly. The instruments used for this psychosocial evaluation differ in their focus, with some assessing overall psychosocial functioning while others only measuring specific aspects (e.g., alcohol/drug use, depression, memory), providing a narrower focus. Nghiem et al.'s review of psychosocial assessment instruments for liver and kidney transplant candidates further confirms the scarcity of research on the psychometric properties of these tools and the need to investigate their effectiveness in predicting post-transplantation outcomes (6).

We thus conducted this narrative literature review to summarize the findings on psychosocial assessment tools used before either solid-organ (heart, lung, kidney, and liver) transplantation and their predictions of postoperative outcomes. Although transplant teams might use specific diagnostic tools for different conditions such as depression, substance use or other diseases that may impact transplant outcomes, these were not assessed in this study.

The PRISMA search strategy was used as a model to conduct this narrative review (10).

We reviewed the literature on psychosocial questionnaires used to assess preoperatively solid-organ and their potential utility in predicting different post-transplantation outcomes. We herein outlined the different tools available and summarize the results of published studies on their predictive ability.

The first observation is the relative scarcity of available data on this topic despite the almost universal use of these surveys in clinical practice, a finding that has also been previously recognized by Nghiem et al. (6). Indeed, out of the six psychosocial questionnaires presented in Table 1, only four had available evidence on their pre-transplant use and association with postoperative outcomes. Consequently, two potentially relevant scales, the MBMD and the SIRT, could not even be included in this narrative review. Although these two older questionnaires, from the early 2000s, may be considered outdated compared to newer tools such as the SIPAT or the PACT, described in the late 2010s, it is still noteworthy that no investigator has ever focused on their predictive aspect. Also, of the remaining four questionnaires ultimately included in this literature review, we found an average of only three reports per questionnaire (ranging from two to four), highlighting the need for more research on this understudied field despite its wide clinical acceptance.

Overall, as summarized in Table 3, of the thirteen studies included, nineteen primary outcomes were verified, and twelve were significantly associated with the results of the pre-transplant evaluation, demonstrating that the predictive capacity of psychosocial scales is good but somewhat imperfect. However, it is worth noting various elements of these included articles that may have an impact on their conclusions. First, it should be noted that the various studies included did not have a standardized methodology, which also limits the conclusions that can be drawn from them. Also, the calculation of the sample size necessary to observe a significant difference (the power) was not presented in many of the different studies, which render difficult the determination of whether the absence of significance is due to a lack of power or to a real lack of predictive capacity of the scale. Furthermore, despite the recognition that choosing a threshold that maximizes sensitivity and selectivity is paramount for identifying patients at risk (30), evidence for the choice of the threshold is not always mentioned. An inadequate threshold could therefore weaken prediction of post-transplant outcomes.

Interestingly, all the outcomes that were nonsignificant were medical in nature (the breakdown between medical and psychosocial outcomes is shown in Table 3). It is not surprising that some of these scales were able to predict psychosocial outcomes following transplantation but were somewhat imperfect for assessing medical outcomes. These results reinforce the idea that medical outcomes are not necessarily related to psychosocial behaviour, but more importantly to other outcomes, such as hospitalizations or recurrent illnesses. This finding also highlights the importance of the multidisciplinary evaluation of the transplant candidates.

Nevertheless, it is still impressive that almost half the studies had significant association with medical outcomes. We are not aware of a reverse situation, in which a physical health scale would predict psychosocial outcomes. Anyhow, future studies are necessary to refine and maximize the predictive aspect of these tools, possibly by using specific psychosocial domains rather than total scores, as suggested by Olt et al. (31) to assess the association with post-transplant outcomes. However, it should be noted that an inherent limitation of the included studies and study populations is that post-transplant outcomes are only assessed in patients who have effectively received the transplant. Thus, investigators are testing the predictive powers of the scales in those who probably had higher scores at baseline, which may underestimate their efficacy. It is also worth mentioning that some follow-up times, such as that for SIPAT, with patients followed for one year, may be insufficient to capture certain medical outcomes, such as mortality/survival. Other teams, such as the ones evaluating TERS, have followed patients for up to 5 years, with significant results for these medical outcomes.

With these results in mind, it is clear that the involvement of a trained clinical psychologist within the transplant team remains the standard of care considering the complexity of each and every person's life conditions and preferences. The use of psychosocial questionnaires may be considered as a screening tool which helps the transplant team regarding the care of each patient. These questionnaires can be helpful in revealing major contraindications to transplant, thus guiding the need for different interventions with certain populations in order to determine if certain patients may benefit from early interventions which could result in eventual transplantation.

This narrative literature review evaluated different widely used scales assessing the psychosocial characteristics of the patients, which is an integral part of the transplantation candidacy process for solid organ transplantation, and their predictive value on postoperative outcomes. Regarding our initial interrogation as if psychosocial assessment tools for use before transplantation or mechanical circulatory support were predictive of postoperative outcomes, the definite answer should be “yes” for what they are deemed to measure, i.e., psychosocial and health behavior outcomes, and indeterminate for the physical health outcomes. Of the thirteen articles included, an association with pre-transplant scores could be found for more than half of the nineteen postoperative primary outcomes tested, with TERS and MBHI having the higher number of positive (statistically significant) studies. The overall mixed evidence towards the predictive value of the different scales remains a real challenge for transplantation teams, given the limited number of donors and the need to allocate this resource to the most suitable candidates. Consequently, evidence from well conducted clinical trials are urgently needed to empower the transplantation teams worldwide in their predictive capacity during the evaluation of the transplant candidates; our review suggests that this may only come through a multidisciplinary lens.