Adherence to medical recommendations in pediatric transplant recipients: time for action

Demographic Factors, Medication Adherence, and Post-transplant Health Outcomes: A Longitudinal Multilevel Modeling Approach

Few studies in pediatric solid organ transplantation have examined non-adherence to immunosuppressive medication over time and its associations with demographic factors and post-transplant outcomes including late acute rejection and hospitalizations. We examined longitudinal variation in patient Medication Level Variability Index (MLVI) adherence data from pediatric kidney, liver, and heart transplant recipients. Patient and administrative data from the United Network for Organ Sharing were linked with electronic health records and MLVI values for 332 patients. Multilevel mediation modeling indicated comparatively more variation in MLVI values between patients than within patients, longitudinally, over 10 years post transplant. MLVI values significantly predicted late acute rejection and hospitalization. MLVI partially mediated patient factors and post-transplant outcomes for patient age indicating adolescents may benefit most from intervention efforts. Results demonstrate the importance of longitudinal assessment of adherence and differences among patients. Efforts to promote medication adherence should be adapted to high-risk patients to increase likelihood of adherence.

Prediction of Outcomes After Heart Transplantation in Pediatric Patients Using National Registry Data: Evaluation of Machine Learning Approaches

BACKGROUND

The prediction of posttransplant health outcomes for pediatric heart transplantation is critical for risk stratification and high-quality posttransplant care.

OBJECTIVE

The purpose of this study was to examine the use of machine learning (ML) models to predict rejection and mortality for pediatric heart transplant recipients.

METHODS

Various ML models were used to predict rejection and mortality at 1, 3, and 5 years after transplantation in pediatric heart transplant recipients using United Network for Organ Sharing data from 1987 to 2019. The variables used for predicting posttransplant outcomes included donor and recipient as well as medical and social factors. We evaluated 7 ML models-extreme gradient boosting (XGBoost), logistic regression, support vector machine, random forest (RF), stochastic gradient descent, multilayer perceptron, and adaptive boosting (AdaBoost)-as well as a deep learning model with 2 hidden layers with 100 neurons and a rectified linear unit (ReLU) activation function followed by batch normalization for each and a classification head with a softmax activation function. We used 10-fold cross-validation to evaluate model performance. Shapley additive explanations (SHAP) values were calculated to estimate the importance of each variable for prediction.

RESULTS

RF and AdaBoost models were the best-performing algorithms for different prediction windows across outcomes. RF outperformed other ML algorithms in predicting 5 of the 6 outcomes (area under the receiver operating characteristic curve [AUROC] 0.664 and 0.706 for 1-year and 3-year rejection, respectively, and AUROC 0.697, 0.758, and 0.763 for 1-year, 3-year, and 5-year mortality, respectively). AdaBoost achieved the best performance for prediction of 5-year rejection (AUROC 0.705).

CONCLUSIONS

This study demonstrates the comparative utility of ML approaches for modeling posttransplant health outcomes using registry data. ML approaches can identify unique risk factors and their complex relationship with outcomes, thereby identifying patients considered to be at risk and informing the transplant community about the potential of these innovative approaches to improve pediatric care after heart transplantation. Future studies are required to translate the information derived from prediction models to optimize counseling, clinical care, and decision-making within pediatric organ transplant centers.

Remote intervention engagement and outcomes in the Clinical Trials in Organ Transplantation in Children consortium multisite trial

Remote interventions are increasingly used in transplant medicine but have rarely been rigorously evaluated. We investigated a remote intervention targeting immunosuppressant management in pediatric lung transplant recipients. Patients were recruited from a larger multisite trial if they had a Medication Level Variability Index (MLVI) ≥2.0, indicating worrisome tacrolimus level fluctuation. The manualized intervention included three weekly phone calls and regular follow-up calls. A comparison group included patients who met enrollment criteria after the subprotocol ended. Outcomes were defined before the intent-to-treat analysis. Feasibility was defined as ≥50% of participants completing the weekly calls. MLVI was compared pre- and 180 days postenrollment and between intervention and comparison groups. Of 18 eligible patients, 15 enrolled. Seven additional patients served as the comparison. Seventy-five percent of participants completed ≥3 weekly calls; average time on protocol was 257.7 days. Average intervention group MLVI was significantly lower (indicating improved blood level stability) at 180 days postenrollment (2.9 ± 1.29) compared with pre-enrollment (4.6 ± 2.10), p = .02. At 180 days, MLVI decreased by 1.6 points in the intervention group but increased by 0.6 in the comparison group (p = .054). Participants successfully engaged in a long-term remote intervention, and their medication blood levels stabilized. NCT02266888.

Examining the association of medical complications and posttraumatic stress symptoms in pediatric solid organ transplant patients and their caregivers

BACKGROUND

Post-traumatic stress symptoms (PTSS) have been reported by pediatric solid organ transplant (SOT) patients and their caregivers well after transplantation. This study examined the relationship between PTSS, medication adherence, and medical complications in SOT patients and their caregivers. A secondary aim examined the association between patient and caregiver-reported PTSS.

METHODS

Pediatric SOT patients (N = 69) and caregivers (N = 73) reported on PTSS by completing the Child PTSD Symptom Scale (patients 8-17 years) or the Impact of Events Scale-Revised (patients 18 years and older and caregivers). Patient medication adherence was assessed using the Medication Level Variability Index (MLVI). Patients were dichotomized as experiencing a post-transplant medical complication (ie, transplant-related hospital admission prior to the year completing measures of PTSS) or no complications.

RESULTS

Medication adherence was not significantly associated with patient or caregiver PTSS. A moderate effect size was found for elevated young adult and caregiver PTSS and the presence of a medical complication. Generally, the association between self-reported patient and caregiver PTSS was low.

CONCLUSIONS

The presence of elevated PTSS in young adult patients may be partially explained by the presence of proximal medical complications and more so by comorbid psychiatric diagnoses in child and adolescent patients (based on exploratory analyses). Caregivers of patients with medical complications within the past year reported higher levels of PTSS. Overall, transplantation and its associated impact on PTSS may be unique experience for patients versus caregivers. Qualitative research may further elucidate these experiences and inform future clinical interventions.

Machine learning-based prediction of health outcomes in pediatric organ transplantation recipients

OBJECTIVES

Prediction of post-transplant health outcomes and identification of key factors remain important issues for pediatric transplant teams and researchers. Outcomes research has generally relied on general linear modeling or similar techniques offering limited predictive validity. Thus far, data-driven modeling and machine learning (ML) approaches have had limited application and success in pediatric transplant outcomes research. The purpose of the current study was to examine ML models predicting post-transplant hospitalization in a sample of pediatric kidney, liver, and heart transplant recipients from a large solid organ transplant program.

MATERIALS AND METHODS

Various logistic regression, naive Bayes, support vector machine, and deep learning (DL) methods were used to predict 1-, 3-, and 5-year post-transplant hospitalization using patient and administrative data from a large pediatric organ transplant center.

RESULTS

DL models generally outperformed traditional ML models across organtypes and prediction windows with area under the receiver operating characteristic curve values ranging from 0.750 to 0.851. Shapley additive explanations (SHAP) were used to increase the interpretability of DL model results. Various medical, patient, and social variables were identified as salient predictors across organ types.

DISCUSSION

Results demonstrate the utility of DL modeling for health outcome prediction with pediatric patients, and its use represents an important development in the prediction of post-transplant outcomes in pediatric transplantation compared to prior research.

CONCLUSION

Results point to DL models as potentially useful tools in decision-support systems assisting physicians and transplant teams in identifying patients at a greater risk for poor post-transplant outcomes.

Assessment and Treatment of Nonadherence in Transplant Recipients

Stable intake of an immunosuppressant medication regimen is essential for posttransplant survival in the vast majority of cases. And yet, many patients are nonadherent (do not take their medications as prescribed), and suffer consequences ranging from rejection to morbidity and mortality. We review the evidence related to monitoring of adherence to medications, and intervention strategies. Our aim is to provide a baseline from which readers may approach behavioral aspects of posttransplant care. This review may also help readers in designing clinical programs for routine monitoring of adherence, and inform the choice of intervention when adherence falls below a certain threshold.

Improvements in intestine transplantation

Transplantation of the intestine in children has presented significant challenges even as it has become a standard to treat nutritional failure due to short gut syndrome. These challenges have been addressed in part by significant improvements in short and long-term care. Noteworthy enhancements include reduced need for intestine transplantation, drug-sparing immunosuppressive regimens, immune monitoring, and improved surveillance and management of PTLD and non-adherence.

Psychosocial predictors of medication non-adherence in pediatric organ transplantation: A systematic review

Adherence to immunosuppressant medication is critical to health and quality-of-life outcomes for children who have received a solid organ transplant. Research on the psychological and social predictors of medication adherence is essential to the advancement of pretransplant assessments and transplant psychosocial services. Despite the importance of identifying risk factors, the literature remains limited regarding psychosocial predictors of non-adherence. A systematic search was conducted to identify studies of the psychosocial predictors of post-transplant medication non-adherence in pediatric solid organ transplantation. From 1363 studies identified in searches of empirical literature, a final sample consisted of 54 publications representing 49 unique studies. Findings regarding psychosocial predictors were inconsistent with non-adherence associated largely with adolescence, racial/ethnic minority status, and presence of mental health issues. Familial predictors of non-adherence problems included single-parent households, lower socioeconomic status, lower family cohesion, presence of family conflict, and poor family communication. Several studies reported an association between non-adherence and social pressures (eg, peer social interaction, wanting to feel normal) among adolescent transplant recipients. While significant methodological and substantive gaps remain in this body of knowledge, this review synthesizes current evidence for assessment for transplant clinicians and researchers.

A systematic review of immunosuppressant adherence interventions in transplant recipients: Decoding the streetlight effect

Non-adherence to immunosuppressant medications is an important risk factor for graft dysfunction. To evaluate the effectiveness of adherence-enhancing interventions, we reviewed adherence intervention studies in solid organ transplant recipients (all ages). Using the following databases: PsycINFO, PubMed, Scopus, and ScienceDirect, we identified 41 eligible studies. Only three non-randomized trials showed a possible positive effect on objective indicators of transplant outcomes (such as rejection, liver enzyme levels, kidney function). None of the 21 RCTs showed an improvement in transplant outcomes. Three studies showed a higher rate of adverse events in the intervention group as compared with controls, although this may be related to ascertainment bias. Improvement in adherence as measured indirectly (eg, with electronic monitoring devices) was not aligned with effects on transplant outcomes. We conclude that adherence interventions, to date, have largely been ineffective in improving transplant outcomes. To improve this track record, intervention efforts may wish to concentrate on non-adherent patients (rather than use convenience sampling, which excludes many of the patients who need the intervention), use direct measures of adherence to guide the interventions, and employ strategies that are intensive and yet engaging enough to ensure that non-adherent patients are able to participate.

The Medication Level Variability Index (MLVI) Predicts Poor Liver Transplant Outcomes: A Prospective Multi-Site Study

Nonadherence to immunosuppressant medications is a leading cause of poor long-term outcomes in transplant recipients. The Medication Level Variability Index (MLVI) provides a vehicle for transplant outcome risk-stratification through continuous assessment of adherence. The MALT (Medication Adherence in children who had a Liver Transplant) prospective multi-site study evaluated whether MLVI predicts late acute rejection (LAR). Four hundred pediatric (1-17-year-old) liver transplant recipients were enrolled and followed for 2 years. The a-priori hypothesis was that a higher MLVI predicts LAR. Predefined secondary analyses evaluated other outcomes such as liver enzyme levels, and sensitivity analyses compared adolescents to pre-adolescents. In the primary analysis sample of 379 participants, a higher prerejection MLVI predicted LAR (mean prerejection MLVI with LAR: 2.4 [3.6 standard deviation] versus without LAR, 1.6 [1.1]; p = 0.026). Fifty-three percent of the adolescents with MLVI>2 in year 1 had LAR by the end of year 2, as compared with 6% of those with year 1 MLVI≤2. A higher MLVI was significantly associated with all secondary outcomes. MLVI, a marker of medication adherence that uses clinically derived information, predicts LAR in pediatric liver transplant recipients.

Intrapatient Variability in Tacrolimus Exposure Does Not Predict The Development of Cardiac Allograft Vasculopathy After Heart Transplant

OBJECTIVE

A high intrapatient variability in tacrolimus exposure is associated with poor long-term outcomes after kidney transplant. We hypothesized that a high intrapatient variability of tacrolimus exposure after heart transplant may be associated with cardiac allograft vasculopathy as a determinant of long-term survival of heart transplant recipients.

MATERIALS AND METHODS

Eighty-six heart transplant recipients were included. Patients underwent coronary angiography at years 1 and 4 after transplant and were divided according to low and high intrapatient variability of tacrolimus exposure, with the median variability as cut-off. The primary outcome was the association between tacrolimus intrapatient variability and the progression of cardiac allograft vasculopathy score between years 1 and 4. Secondary outcome was this association with acute cellular rejection.

RESULTS

There was no significant difference in the proportion of patients with high tacrolimus intrapatient variability in the group that progressed to higher grades of cardiac allograft vasculopathy (n = 15) versus the group without progression (n = 71) at 4-year follow-up (60.0% vs 47.9%; P = .57). There was no significant difference in the proportion of patients with high tacrolimus intrapatient variability between the 58 patients with 1 or more acute cellular rejection episodes and the 28 patients without rejection (51.7% vs 46.4%; P = .82).

CONCLUSIONS

A high intrapatient variability in tacrolimus exposure does not appear to influence heart transplant outcomes, unlike its influence on kidney transplant function. A higher immunosuppression exposure after heart transplant, including the use of prednisone often in a combination of 3 immunosuppressive drugs, may protect against the effects of high intrapatient tacrolimus variability.

An empirically based practice perspective on the transition to adulthood for solid organ transplant recipients

Preparing patients for transitioning to self-managed care and subsequently transferring to the adult healthcare system has become a critical process for clinicians working with pediatric transplant recipients. This paper reviews several barriers to a successful transition. These include patient barriers, caregiver barriers, and considerations within pediatric and adult centers. To date, few approaches for improving the transition process have been empirically tested. This review details studies that have examined possible models including usage of a transition coordinator and transition clinics. Recommendations are offered to promote an optimal transition including the importance and content of preparation, assessing and addressing transition readiness, insuring the involvement of all stakeholders, and finally, at minimum providing services during the transfer period. Future directions are offered aiming to advance this important area of investigation.

Medication level variability index predicts rejection, possibly due to nonadherence, in adult liver transplant recipients

Nonadherence to immunosuppressants may play a role in late rejection in liver transplant recipients. In children, emerging data suggest that adherence can be measured through the computation of the standard deviation (SD) of consecutive blood levels of tacrolimus, which results in a number that reflects the degree of variability between individual measures: the medication level variability index (MLVI). A higher MLVI value means erratic immunosuppression, likely due to less adherence. Data on this method are limited for adults. We obtained data from the medical charts of 150 randomly selected adult recipients. The MLVI was significantly higher for patients who had biopsy-confirmed rejection (mean MLVI = 3.8, SD = 3.2) versus the rest of the cohort (mean MLVI = 2.3, SD = 1.5, P = 0.003), and it was significantly higher for patients who suffered rejection versus patients whose biopsy sample was not read as rejection (mean MLVI = 2.6, SD = 1.6, P = 0.008). The MLVI was associated with rejection and predicted its occurrence. A threshold MLVI of 2.0 resulted in 77% sensitivity and 60% specificity in predicting rejection; a threshold of 1.8 resulted in a sensitivity of 92% and a specificity of 48%. The area under the curve in a receiver operating characteristic curve analysis was 0.71 (95% CI = 0.61-0.81). In conclusion, the MLVI is associated with and can predict rejection, possibly related to nonadherence, in adult liver transplant recipients.

Psycho-social outcome in liver transplanted children: beware of emotional self-assessment!

Background

Psycho-social outcome in children after liver transplantation (LT) is known to be inferior to age-related peers. Yet, when children and their parents are questioned by their nurse or physician about the child’s psycho-social well-being, the answers usually are very positive. We hypothesized that patients and their parents after LT report their psycho-social well-being too enthusiastically when enquired by their personal care takers.

Methods

Inclusion criteria: LT at the Children’s University Hospital of Geneva 1992–2007, age >3 years, <16 years, time after LT >2 years. Children and their parents were questioned by their well-known, familiar nurse at the annual follow up visit about their personal well-being. To allow for evaluation of answers, scores (good, medium, bad) were attributed to the different questions. 46 children were included in the study.

Results

Mean age at enquiry was 9.7 years (SD 4 years), mean time after LT was 7.5 years (SD 4.2 years). The different themes were reported as good for: parent–child relationship (83%), relationship with peers (98%), relation with siblings (39%), sport activities (54%), play activities (78%), school performance (87%), expression skills (67%), and general behavior (89%).

Conclusion

Most of our LT children and their parents consider, during a personal interview with a closely related, familiar nurse, that the child’s psycho-social outcome is good. Yet, it is generally acknowledged that children after LT have negatively altered psycho-social outcomes. Thus, emotionally influenced reports about psycho-social outcome in children after LT must be looked at with care.

Variability in tacrolimus blood levels increases the risk of late rejection and graft loss after solid organ transplantation in older children

  Late graft rejection impairs the long-term function of organ transplants in children. Previous studies suggest patients with wide variation in tacrolimus levels may have higher rates of late kidney and liver graft rejection. The reproducibility of this finding and impact on graft and recipient survival have not been reported. We investigated factors associated with late rejection > 6 months post-transplant in 144 heart, kidney, liver, and lung transplant recipients (ages 8-18, ≥ 1-yr survivors, receiving tacrolimus-based immunosuppression), comparing late rejectors (n = 61, 42%) to non-rejectors (no rejection > 6 months); groups had similar mean tacrolimus concentrations ≤ 6 months post-transplant. For all organ types, increased standard deviation in intrapatient tacrolimus blood levels was an independent risk factor for late rejection (OR 1.6 [CI 1.1-2.1]; p = 0.02). Each 1-point increase in s.d. > 2 of tacrolimus level > 6 months post-transplant associated with 1.58 increase in hazard of graft loss (p = 0.003). Graft survival (conditional on one-yr survival) was significantly better for those with s.d. < 2 at > 6 months post-transplant: 98% at three and five yr, versus 88%, 70%, at three and five yr, in patients with s.d. > 2 (p = 0.003). In conclusion, high s.d. in serial tacrolimus concentrations associated with increased risk of late rejection and graft loss in pediatric organ transplant recipients, providing opportunities for screening and interventions.

Adherence to medical recommendations and transition to adult services in pediatric transplant recipients

PURPOSE OF REVIEW

Nonadherence to treatment recommendations, especially when associated with transition to adult care providers, account, by some estimates, for most organ rejections and death in long-term pediatric survivors of solid organ transplantations. It is therefore imperative that providers become familiar with the issues related to those major risks and ways to address them.

RECENT FINDINGS

It is possible, and important, to routinely measure adherence to medications by using one of several available and proven methods of surveillance. There are numerous ways to improve adherence, and it is in fact possible to improve adherence and therefore outcomes in the transplant setting. The transition to adult services is a vulnerable period. The authors believe that it is possible to improve the transition process, and suggestions are presented in this review. However, solid research into interventions to improve transition is lacking.

SUMMARY

Nonadherence to medical recommendations is prevalent and leads to poor outcomes following otherwise successful pediatric transplantation. An especially vulnerable period is the time when a recipient transitions to adult care. Routine monitoring of adherence, evaluating and addressing barriers to adherence, and collaborative, multidisciplinary care are all expected to substantially improve adherence and reduce the risks associated with transition.

Long-term outcomes in pediatric liver transplantation

1. Critical clinical outcomes for pediatric liver transplantation (LT) recipients include (1) patient and graft survival, (2) complications (immune and nonimmune) of chronic immunosuppressive medications, and (3) long-term graft function. 2. Recurrence of malignancy, sepsis, and posttransplant lymphoproliferative disorder account for more than 65% of deaths occurring more than 1 year after LT. 3. Chronic rejection, late hepatic artery thrombosis, and biliary strictures account for 70% of graft loss occurring more than 1 year after LT. 4. Late histological changes in the allograft are emerging as a common problem in patients more than 5 years after LT. The pathogenesis of these findings and the impact on graft survival remain to be determined.