The psychosocial assessment of candidates for transplantation:a prospective cohort study of its association with mortality among kidney transplant candidates

doi:10.21203/rs.3.rs-4363213/v1

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The psychosocial assessment of candidates for transplantation:a prospective cohort study of its association with mortality among kidney transplant candidates

https://doi.org/10.21203/rs.3.rs-4363213/v1

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Background

A psychosocial assessment is an important part of the pre-transplant evaluation.

Aims

To assess the association between scores on the global Psychosocial Assessment of Candidates Transplant tool and survival in deceased donor kidney transplant candidates.

Methods

In this prospective longitudinal study, the participants were registered candidates on the waiting list for deceased donor kidney transplants at a transplant center in South Korea. Initially, candidates enrolled in this study in 2016 were divided into high- and low-psychosocial risk cohorts using a Psychosocial Assessment of Candidates Transplant score cutoff of 3 points. In 2022, the mortality rate was compared according to whether the initial Psychosocial Assessment of Candidates Transplant score was < 3 or ≥ 3 points.

Results

This study included 139 deceased donor kidney transplant candidates, of whom 32 (23.0%) received kidney transplantation. An initial Psychosocial Assessment of Candidates Transplant score < 3 was associated with higher mortality 5 years after being placed on the waiting list (hazard ratio = 12.28, p = 0.017). Current alcohol use at baseline was associated with higher mortality 5 years after being placed on the waiting list (hazard ratio = 12.93, p = 0.032).

Conclusions

Both a high risk of psychosocial candidacy and current alcohol use were associated with significantly reduced survival 5 years after placement on the waiting list for a deceased donor kidney transplant. The psychosocial status of candidates on the waitlist for kidney transplantation should be regularly screened and systematically managed to improve their psychosocial status and reduce alcohol use to make them more suitable candidates for transplant surgery. A psychosocial intervention should be developed for patients on the waiting list to improve their psychosocial status and promote positive health outcomes after kidney transplantation.

kidney transplantation

psychology

assessment

waiting list

Kidney transplantation is the preferred replacement therapy for end-stage renal disease due to the expenses, poor survival outcomes, and impaired quality of life associated with maintenance dialysis (4, 5). However, not all patients are suitable candidates for kidney transplantation. Risk estimation is a key component of evaluating candidates for kidney transplantation because suitability is often determined by the perceived risks of transplantation relative to the risks of not receiving a transplant. Physical, psychosocial, and financial strategies are essential to ensure that candidates are in an acceptable condition for kidney transplantation when an organ becomes available.

In particular, according to the Kidney Disease Improving Global Outcomes guidelines, a psychosocial assessment is an essential component of the evaluation of kidney transplantation candidates (6). Psychosocial factors are important because transplantation is typically a highly complex procedure requiring frequent pre- and post-transplant medical care, as well as rehabilitation (7). Furthermore, the psychosocial status of candidates affects transplant outcomes and persists after transplantation (8). Despite the importance of psychosocial factors, there are no standardized criteria for assessing candidates’ psychosocial status before kidney transplantation (9). The extant guideline from the UNOS regarding the psychosocial evaluation process is too broad and provides insufficient concrete directions. Since it is important to assess candidates using a transplant-specific tool, an instrument for evidence-based psychosocial risk assessment would greatly improve transplant candidacy (7). A few studies have reported significant associations between pre-transplant psychosocial risk assessed using transplant-specific tools and post-transplant mortality in patients undergoing lung and liver transplantation. For this purpose, three validated and widely used tools exist: the Psychosocial Assessment of Candidates for Transplant (PACT) scale (10), the Transplant Evaluation Rating Scale (TERS) (11), and the Stanford Integrated Psychosocial Assessment for Transplantation (SIPAT) scale (9). For example, in female liver transplant recipients, lower PACT scores were associated with a higher risk of post-transplant mortality (12). SIPAT scores were associated with the risk of allograft rejection after liver transplantation (13).

However, the retrospective design of these previous studies limits their interpretation. Furthermore, inconsistent findings have been reported regarding the association between psychosocial risk and transplant outcomes including mortality (12). No studies have investigated this issue among patients waiting for a kidney transplant. As discussed above, the kidney transplant waiting time is increasing worldwide (14). This issue is especially serious in Korea, where there is no waiting list management program (15). Therefore, in this study, given Korea's average kidney transplant waiting period, we utilized a prospective cohort design to explore whether psychosocial risk, determined using the PACT score, was associated with 5-year mortality among candidates on the waitlist for deceased-donor kidney transplantation (DDKT).

Study design, participants, and sampling

A prospective longitudinal study was conducted from 2016 to 2022. Participants were recruited from a transplant center in Korea. The participants were required to be at least 19 years of age, to be registered as a candidate in KONOS, and to have visited the transplant center at least once to receive the routine 30-minute education providing guidance about preparing for DDKT from the kidney transplantation coordinator. In total, 142 people on the waiting list were initially registered at baseline (2016).

During the 5-year follow-up period, three candidates on the waiting list were transferred to other hospitals. Therefore, we were able to collect research data on 139 participants during the 5-year study period.

Measurements

The PACT is an eight-item semi-structured instrument that evaluates four domains: social support, psychological health, lifestyle factors (including substance use and compliance with medications), and understanding of transplant and follow-up care. Each item is scored on a range from 0 (worst score) to 4 (best score); thus, a lower score indicates higher psychosocial risk. The final global assessment is an evaluator's integration of all items into a single final score, which is interpreted as follows: 0, poor candidate; 1, borderline candidate; 2, acceptable candidate; 3, good candidate; and 4, excellent candidate. We used the mean PACT score assigned during the initial pretransplant assessment as the primary covariate of interest. Candidates with a PACT score < 3 (poor, borderline, and acceptable candidates) were considered to have high psychosocial risk, while those with a PACT score ≥ 3 (good and excellent candidates) were considered to have low psychosocial risk (stable). This cutoff value was determined based on a calculation of the area under the curve among Korean DDKT candidates (16).

Data collection

Baseline data (2016), including the PACT score and demographic and clinical data, were collected through structured questionnaire-based interviews with participants, as well as from participants' medical records and KONOS data. A researcher approached eligible patients after a routine medical checkup and asked whether they wanted to participate in this study. Each participant was interviewed once in order to complete the psychosocial assessment using the PACT scale. The psychosocial assessment was carried out by a KONOS-registered transplantation coordinator with over 10 years of work experience in kidney transplantation, based on information obtained from a comprehensive interview as well as discussions with the participant's social worker and nephrologist. All DDKT candidates received a routine physical evaluation at 1 year of follow-up in order to determine their suitability for kidney transplantation surgery. At this time, a blood sample was obtained and saved for later crossmatch testing with blood from a brain-dead donor. After 5 years, follow-up data were collected through medical records and KONOS data to identify whether participants received kidney transplantation and whether they died.

Statistical analysis

Demographic data, other baseline characteristics, and PACT scores were presented as mean, standard deviation (SD), frequency, and percentage. The chi-square test was used to compare patients’ characteristics in terms of PACT status. The survival time was calculated as the interval between the date of the first interview (2016) and the date of the last assessment in patients’ medical chart review (2022) or the date of death. To compare survival trends based on PACT status, a Kaplan-Meier curve was constructed and the log-rank test was used. Cox proportional hazard regression analysis was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for PACT status. Adjustments were made for baseline demographic data (age, gender, marital status), socioeconomic status (insurance), and health-related activities in all Cox proportional hazards models (cigarette smoking and alcohol consumption). The likelihood ratio, Wald test, and score test were used to assess the overall goodness of fit, while the Schoenfeld residuals test was employed to assess the validity of the proportional hazard assumptions (17, 18)(Clark et al., 2003, In and Lee, 2019). The statistical analyses were performed using R version 4.2.2 (R Foundation for Statistical Computing), and a p-value < 0.05 was considered to indicate statistical significance.

Ethical considerations

This research project received approval from a National University Hospital Institutional Review Board (No. 2015-07-008-002). The participants were informed about the study's purpose, data collection procedures, the right to discontinue participation in the study at any time, and the protection of their privacy. All participants agreed to participate and signed an informed consent form.

In the first baseline year (2016), 139 patients were included in the study and completed the PACT assessment. The average age of the patients was 52.3 years (SD: 11.0 years; range: 19–72 years), and there were 55 women (39.6%). Most of the patients (n = 107; 77.0%) were married. 96 (69.1%) of patients had rare incurable disease national inssurance. Forty-six (33.1%) were current cigarette smokers, and 56 (40.3%) drank alcohol. Furthermore, 91 individuals (65.5%) were categorized as having a high-risk psychosocial status (PACT < 3), while 48 (34.5%) were classified as stable (PACT ≥ 3) (Table 1).

Table 1

General characteristics of the study participants (N = 139)
Characteristics		n	%	mean	SD
Age (years)				52.3	11.0
Gender	Male	84	60.4
	Female	55	39.6
KT	Received	32	23.0
	Not received	107	77.0
Married	Married	107	77.0
	Others (Divorced, Withdraw, Single)	32	23.0
Insurance	Medicare	96	69.1
	Medicaid	43	30.9
Smoking	Never	73	52.5
	Former	20	14.4
	Current	46	33.1
Alchohole use	Never	20	14.4
	Former	63	45.3
	Current	56	40.3
PACT score	PACT < 3	91	65.5
	PACT ≥ 3	48	34.5
KT; Kidney Transplantation, HD;Hemodyalysis, PD;Peritorealdyalysis, SD;Standard Deviation,
PACT; Psychosocial Assessment of Candidates Transplant score

During the 5 year follow-up from 2016 to 2022, 32 (23.0%) candidates received kidney transplantation, with 17 (12.2%) deaths among all DDKT candidates. As shown in Table 2, insurance status, cigarette smoking, and alcohol consumption showed significant differences according to the PACT score. Insurance coverage(Rare incurable disease), current alcohol use, and current cigarette smoking were more common among those with PACT scores < 3 than those with PACT scores ≥ 3.

Table 2

Baseline characteristics of the study participants by PACT (N = 139)
		PACT < 3 (n = 91)	PACT ≥ 3 (n = 48)
Characteristics		n(%)	n(%)	p
Age (years)		50.81 ± 11.46	55.08 ± 9.83	0.095
Gender	Male	71 (78.0)	36 (75.0)	0.069
	Female	20 (22.0)	12 (25.0)
KT	Received	20 (22.0)	12 (25.0)	0.687
	Not received	71 (78.0)	36 (75.0)
Married	Married	65 (71.4)	26 (12.5)	0.032
	Single	26 (28.6)	42 (87.5)
Insurance (Rare incurable disease)	Yes	54 (59.3)	42 (87.5)	< 0.001
	No	37 (40.7)	6 (12.5)
Smoking	Never	51 (56.0)	22 (45.8)	< 0.001
	Former	25 (15.4)	6 (12.5)
	Current	26 (28.6)	20 (41.7)
Alcohol use	Never	16 (17.6)	4 (8.3)	< 0.001
	Former	41 (45.1)	22 (45.8)
	Current	34 (37.4)	22 (45.8)

The log-rank test using the Kaplan-Meier method showed that DDKT candidates with high-risk psychosocial status (PACT < 3) at baseline had significantly lower survival probabilities than those categorized as having a stable psychosocial status (PACT ≥ 3) (p < 0.001; Fig. 1). The Schoenfeld residuals test demonstrated that the proportional-hazards assumption was met (Fig. 2).

Table 3 shows the relationship between psychosocial status and mortality based on PACT score. The likelihood ratio test, Wald test, and score test demonstrated statistical significance of the Cox regression models, and no violation of the proportional-hazards assumption was found. After adjusting for all covariates, the high-risk psychosocial status group (PACT < 3) showed a 12.28 times higher risk of mortality than the stable group (95% CI, 1.54–97.48). Current alcohol use was also associated with an approximately 12.93 times higher risk of mortality in comparison to patients who did not currently use alcohol (95% CI, 1.25–134.40).

Table 3

Cox proportional hazard model for 5-year mortality (N = 139)
Variable (reference group)		aHR	95% CI	p
PACT < 3 (PACT ≥ 3)	Yes	12.28	1.54 ~ 97.48	0.017
Gender (Male)	Female	4.04	0.58 ~ 28.26	0.158
Married (Others)	Yes	0.32	0.09 ~ 1.02	0.054
Insurance (No Rare incurable disease)	Yes	0.62	0.98 ~ 10.93	0.054
Alchohole use (Never)	Current	12.93	1.25 ~ 134.40	0.032
	Former	3.97	0.47 ~ 33.65	0.205
Smoking (Never)	Current	0.43	0.05 ~ 3.79	0.446
	Former	1.80	0.20 ~ 15.78	0.597
Age		1.01	0.96 ~ 1.07	0.602
KT	Yes	0.21	0.03 ~ 1.80	0.156
CI, confidence interval; aHR, adjusted hazard ratio; KT, kidney transplantation

This is the first study in Korea to use a prospective longitudinal cohort design to investigate the predictive ability of psychosocial status for mortality among DDKT candidates on the waitlist over a relatively long follow-up period. Specifically, a major strength of this study is that it used the prospective cohort method to track a group of people with many similarities (i.e., DDKT candidates), but with certain differences in a single characteristic (i.e., psychosocial risk) over time. These aspects of the study design allowed us to overcome the limitations of retrospective studies, such as potential error due to confounding and bias (including recall bias).

We specifically only enrolled participants on the waiting list for DDKT. Those on the waiting list for living-donor kidney transplantation were excluded. It is also noteworthy that all patients were followed up for 5 years, considering that the average waiting time for Korean DDKT candidates is 5–7 years. Candidates on the waiting list must regularly visit the transplant center to receive physical examinations after registering at a transplant hospital and receiving a transplant; therefore, follow-up with 100% of the participants was possible. Furthermore, we utilized a standardized validated psychosocial assessment tool and documented a novel association between a global psychosocial assessment score and mortality in DDKT candidates. Therefore, the PACT tool (with a cutoff score of 3 points) can be regarded as an effective indicator for predicting mortality risk in DDKT candidates in Korea.

We found that the initial psychosocial risk, measured by the PACT scale, was associated with mortality over 5 years of follow-up. The risk of death was 12.28 times higher among participants with an initial PACT score < 3 (high-risk psychosocial status) than among those with a PACT score ≥ 3 (stable psychosocial status) after adjustment for covariates. Current alcohol use at baseline was also associated with a 12.93 times higher risk of mortality compared to non-current alcohol use. The kidney transplant candidacy evaluation is a difficult process that necessitates a thorough examination of each patient's medical, surgical, and psychological histories (19). In particular, since people in East Asian countries such as Korea and China, based on the cultural context of Confucianism, are hesitant to donate organs after brain death (20), psychosocial status is an important issue in DDKT candidates that merits close attention from healthcare providers, especially since the waiting period in Korea is substantially longer than in Western countries.

Turning to previous studies in the literature, the process of preparing for kidney transplantation may be demanding for patients with kidney failure and may present numerous stressors that could increase patients’ vulnerability to psychiatric illnesses and further impede entry to the kidney transplantation queue (20). Moreover, the psychosocial problems of candidates, such as depressive symptoms, affect treatment adherence (21), potentially impacting post-transplant outcomes. Therefore, psychosocial factors are critical throughout the evaluation process and may influence patient selection (22). However, psychosocial status has not generally been evaluated using transplant-specific, standardized assessment tools. In a 2-year follow-up study, psychosocial status (measured using the TERS score) was associated with the risk of graft rejection after kidney transplantation, which supports our main findings (23). Furthermore, some studies on other organ transplant candidates (liver, lung, heart) have examined pre-transplant psychosocial variables and their impact on post-transplant outcome measures, similarly to this study. However, the studies utilizing standardized measures had retrospective designs and inconsistent outcomes. For example, a study showed that the psychosocial status (measured using the PACT scale, with a cutoff score of 2 points) in female candidates for liver transplantation was a significant predictor of post-transplant mortality. However, other studies examining patients waiting for liver, heart, or lung transplantation showed no significant effects of pre-transplant psychosocial status measured using the PACT scale on post-transplant mortality. These discrepancies are thought to be due to differences in study designs and populations. To elucidate the impact of psychosocial status, we plan to examine its association with mortality after kidney transplantation in further follow-up studies.

Our study suggests the need to apply psychosocial interventions and prehabilitation with healthy behavior changes, such as the discontinuation of alcohol use, among pre-kidney transplant candidates. At the same time, transplant professionals should conduct early screening for high-risk psychosocial status using the PACT tool and provide effective strategies to reduce the potential risk of death in DDKT candidates through management programs to improve psychosocial status, aiming for a PACT score ≥ 3. During the transplant process, psychosocial support could also be an important protective factor, since patients awaiting an organ transplant are handling a stressful situation involving substantial uncertainty, which could increase anxiety and depression (24). Psychosocial interventions could lead to improvements both in symptoms and in patients’ adherence to therapy, thereby minimizing risks for DDKT and maximizing the likelihood of a successful transplant outcome.

This study has some limitations. First, the sample was from a single transplant center in Korea. Second, according to the previous literature, the number of events is recommended to be 10 per variable for Cox proportional hazard models (25, 26). Therefore, the relatively low number of events might have threatened the stability of the Cox proportional-hazards model in our study, caused bias in the regression coefficients, and reduced the predictive accuracy.

Candidates who received a low initial PACT score, indicating a high-risk psychosocial status, had a higher risk of death. This finding suggests that a psychosocial assessment using the PACT scale may provide additional mortality risk stratification for DDKT candidates.

RELEVANCE TO CLINICAL PRACTICE

This study adds evidence to the literature on existing global psychosocial assessment tools and expands upon current guidelines. Based on this study’s findings, we suggest that transplant professionals develop a multidisciplinary psychosocial intervention program for patients on the waiting list and conduct research to evaluate its effectiveness.

Ethics approval and consent to participate

This study was approved by the Ethics Committee of Jeonbuk National University Hospital (No: CUH-2015-07-008-002). Written informed consent was obtained from all participants in this study.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

Availability of data and materials

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.

Funding

None

Author Contribution

HJC : Writing - original draft, conceptualization. MKJ : Critical review of the manuscript for important intellectual content, and supervision. HJC and MKJ: Writing - review & editing, Methodology, interpretations of data.

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No competing interests reported.

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Version 1

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You are reading this latest preprint version

The psychosocial assessment of candidates for transplantation:a prospective cohort study of its association with mortality among kidney transplant candidates

Status:

Version 1

Abstract

Background

Aims

Methods

Results

Conclusions

Figures

BACKGROUND

METHODS

Study design, participants, and sampling

Measurements

Data collection

Statistical analysis

Ethical considerations

RESULTS

DISCUSSION

CONCLUSIONS

RELEVANCE TO CLINICAL PRACTICE

Declarations

Funding

Author Contribution

References

Additional Declarations

Status:

Version 1