Stanicki B, Puntiel DA, Peticca B, Egan N, Prudencio TM, Robinson SG, Karhadkar SS. Investigating the controversial link between pediatric obesity and graft survival in kidney transplantation. World J Nephrol 2025; 14(2): 101961 [DOI: 10.5527/wjn.v14.i2.101961]
Corresponding Author of This Article
Sunil S Karhadkar, FACS, MD, Assistant Professor, Department of Surgery, Temple University Hospital, 3401 N Broad Street, Philadelphia, PA 19140, United States. sunil.karhadkar@tuhs.temple.edu
Research Domain of This Article
Transplantation
Article-Type of This Article
Retrospective Cohort Study
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Brooke Stanicki, Dante A Puntiel, Benjamin Peticca, Nicolas Egan, Tomas M Prudencio, Samuel G Robinson, Sunil S Karhadkar, Department of Surgery, Temple University Hospital, Philadelphia, PA 19140, United States
Author contributions: Stanicki B and Puntiel DA led the study design, participated in data analysis, performed statistical analysis in conjunction with the Temple University Center for Biostatistics and Epidemiology and drafted and finalized the manuscript; Peticca B participated in design and oversight of the study and assisted with the data analysis; Egan Nicolas, Prudencio TM, and Robinson SG participated in data analysis and drafting the manuscript; Karhadkar SS participated in oversight of the study, drafted, and finalized the manuscript; all authors read and approved the final manuscript.
Institutional review board statement: This study does not involve human subjects as defined by DHHS or FDA regulations. Consequently, there is no IRB. A Declaration of IRB exemption has been submitted.
Informed consent statement: This study does not involve human subjects as defined by DHHS or FDA regulations. Consequently, there are no informed consent forms.
Conflict-of-interest statement: None of the authors have any conflicts to disclose.
STROBE statement: The authors have read the STROBE statement – checklist of items, and the manuscript was prepared and revised according to the STROBE statement – checklist of items.
Data sharing statement: No additional data are available.
Open Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Sunil S Karhadkar, FACS, MD, Assistant Professor, Department of Surgery, Temple University Hospital, 3401 N Broad Street, Philadelphia, PA 19140, United States. sunil.karhadkar@tuhs.temple.edu
Received: October 8, 2024 Revised: January 2, 2025 Accepted: February 8, 2025 Published online: June 25, 2025 Processing time: 188 Days and 15.8 Hours
Abstract
BACKGROUND
Childhood obesity is a significant public health concern, particularly amongst children with chronic kidney disease requiring kidney transplant (KT). Obesity, defined as a body mass index (BMI) of 30 kg/m² or greater, is prevalent in this population and is associated with disease progression. While BMI influences adult KT eligibility, its impact on pediatric transplant outcomes remains unclear. This study investigates the effect of BMI on graft survival and patient outcomes, addressing gaps in the literature and examining disparities across BMI classifications.
AIM
To assess the impact of BMI classifications on graft and patient survival following KT.
METHODS
A retrospective cohort study analyzed 23081 pediatric transplant recipients from the Standard Transplant Analysis and Research database (1987-2022). Patients were grouped into six BMI categories: Underweight, healthy weight, overweight, and Class 1, 2, and 3 obesity. Data were analyzed using one-way way analysis of variance, Kruskal-Wallis tests, Chi-squared tests, Kaplan-Meier survival analysis with log-rank tests, and Cox proportional hazard regressions. Statistical significance was set at P < 0.05.
RESULTS
Class 3 obese recipients had lower 1-year graft survival (88.7%) compared to healthy-weight recipients (93.1%, P = 0.012). Underweight recipients had lower 10-year patient survival (81.3%, P < 0.05) than healthy-weight recipients. Class 2 and 3 obese recipients had the lowest 5-year graft survival (67.8% and 68.3%, P = 0.013) and Class 2 obesity had the lowest 10-year graft survival (40.7%). Cox regression identified increases in BMI category as an independent predictor of graft failure [hazard ratio (HR) = 1.091, P < 0.001] and mortality (HR = 1.079, P = 0.008). Obese patients experienced longer cold ischemia times (11.6 and 13.1 hours vs 10.2 hours, P < 0.001). Class 3 obesity had the highest proportion of Black recipients (26.2% vs 17.9%, P < 0.001).
CONCLUSION
Severe obesity and underweight status are associated with poorer long-term outcomes in pediatric KT recipients, emphasizing the need for nuanced transplant eligibility criteria addressing obesity-related risks and socioeconomic disparities.
Core Tip: This study investigates the relationship between pediatric obesity and kidney transplant outcomes, addressing a gap in research by analyzing graft survival across body mass index categories. While short-term outcomes for overweight and Class 1 obese pediatric recipients are comparable to healthy-weight peers, Class 2 and 3 obese patients experience significantly reduced long-term graft survival. Underweight recipients also exhibit poorer outcomes, highlighting the dual risks of obesity and malnutrition. The findings highlight the need for individualized transplant criteria and targeted interventions for severely obese children, emphasizing the role of socioeconomic and racial disparities in pediatric kidney transplantation.
Citation: Stanicki B, Puntiel DA, Peticca B, Egan N, Prudencio TM, Robinson SG, Karhadkar SS. Investigating the controversial link between pediatric obesity and graft survival in kidney transplantation. World J Nephrol 2025; 14(2): 101961
The childhood obesity epidemic is a pressing public health issue with far-reaching implications, particularly in the context of medical interventions like kidney transplantation (KT). Obesity, defined as a body mass index (BMI) of 30 kg/m2 or greater, is increasingly common among children with chronic kidney disease (CKD) and has been independently associated with both the progression of CKD and the eventual development of kidney failure[1]. In adults, obesity is a well-established risk factor for adverse KT outcomes, leading to complications including surgical site infections, extended hospital stays, delayed graft function (DGF), and, ultimately, reduced long-term graft and patient survival[2,3]. Both CKD and obesity are associated with systemic inflammation, and their cumulative impact may be the link contributing to poorer graft survival in obese patients. Elevated red cell distribution width, reflecting inflammation, is independently associated with higher mortality in CKD and transplant recipients[4]. Similarly, mean platelet volume, correlated with BMI and waist circumference, highlights the systemic impact of obesity-related inflammation[5]. Because of the well-documented risks of transplantation in obese patients, BMI has become a relative or even absolute contraindication in both pediatric and adult populations, depending on the transplant center. However, the evidence that underpins this policy is largely based on adult studies, with limited empirical data available to guide decisions in pediatric KT. The ethical considerations surrounding the use of BMI as a criterion for pediatric KT are significant and controversial. While some transplant centers recommend obese candidates to lose weight before surgery, the prolonged wait for weight loss can increase the risk associated with extended dialysis, which in itself poses life-threatening complications[6]. In adult obese dialysis patients, there is an "obesity paradox," in which there was a lower risk of death in patients with a BMI between 30-34.9[7]. One hypothesis for this is that obesity may protect against protein-energy wasting; others implicate the dangerous comorbidities associated with a low BMI[8,9]. Regardless of the mechanism, this phenomenon does not carry into the pediatric population, as obesity is associated with increased mortality compared to normal-weight children on dialysis[10]. Despite potential delays, previous literature suggests that weight loss, either achieved by lifestyle modifications or bariatric surgery, can improve transplant outcomes[9]. Additionally, the dynamics of childhood obesity, which are heavily influenced by socioeconomic, genetic, and environmental factors beyond the child's control, further complicate the fairness of using BMI as a strict determinant for eligibility. Pediatric obesity is often linked to systemic inequities, with high rates in Black and Hispanic households, particularly those with lower socioeconomic status[11]. Food insecurity is a durable predictor of the development of obesity, both in childhood and in adulthood[12]. It becomes critical to reassess transplant candidacy criteria that disproportionally affect vulnerable populations, which becomes especially important in pediatrics. Despite the known risks of obesity, little research has been done to evaluate how BMI affects pediatric KT outcomes, and the studies that exist have produced mixed results. This study aims to fill critical gaps in understanding the influence of BMI on pediatric KT outcomes by evaluating survival metrics, including graft and patient survival, across BMI classifications. It further investigates disparities in transplant-related variables among BMI groups and examines the long-term impact of elevated BMI on transplant success. The findings aim to inform and enhance clinical decision-making. We hypothesize that higher BMI is inversely associated with graft and patient survival, with obese recipients experiencing poorer outcomes than their healthy-weight counterparts. Most importantly, we propose that socioeconomic and demographic disparities significantly contribute to outcome variations across BMI groups, specifically within the pediatric population, highlighting the need for equitable and comprehensive transplant criteria.
MATERIALS AND METHODS
Subjects and data collection
The Standard Transplant Analysis and Research (STAR) database was utilized to identify subjects and gather data. This database contains de-identified information on all donors, wait-list candidates, and transplant recipients in the United States. It is managed by the United States Department of Health and Human Services and the Health Resources and Services Administration and is maintained by the United Network for Organ Sharing (UNOS) and the Organ Procurement and Transplantation Network. Given the retrospective nature of the study and the use of de-identified data, it was classified as exempt from formal institutional review by the institutional review board.
Inclusion and exclusion criteria
The STAR/UNOS database was used to identify KT recipients from January 1st, 1987, to December 31st, 2022. Recipients above the age of 18 were excluded. The selection criteria allowed for 23081 pediatric KT recipients to be included, who were further divided into one of six American Academy of Pediatrics BMI Classifications based on growth percentiles for age and sex: Underweight (< 5th percentile); Healthy Weight (5th-85th percentile); Overweight (85th-95th percentile); Class 1 Obesity (95th–120% of the 95th percentile or BMI 35); Class 2 Obesity (BMI = 35 or 120%–140% of the 95th percentile or BMI = 40); Class 3 Obesity ( > 140% of the 95th percentile or BMI = 40). This is outlined in Figure 1. Transplantation eras were selected based on precedents established by previous research to reflect advancements in transplantation practices, ensure a sufficient sample size for statistical analysis, and account for changes in recipient and donor demographics over time[13].
Figure 1 Representation of the separation of all pediatric kidney transplants into body mass index groups.
BMI: Body mass index.
Descriptive and comparative analyses
Statistical analyses were performed using IBM SPSS Statistics Version 30. The normality of continuous variables was assessed using the Kolmogorov-Smirnov test. For continuous variables that conformed to normality, one-way analysis of variance was used to compare differences between groups. For data that did not meet the assumption of normality, the Kruskal-Wallis test was employed as a non-parametric alternative to compare continuous variables across groups. Categorical variables were analyzed using Chi-squared tests. Asymptotic two-tailed significance P-values were reported for continuous and categorical variables. Graft survival (all-cause survival) between groups was evaluated using Kaplan-Meier survival analysis, and survival curves were compared using the log-rank test. Statistical significance for all tests was determined at the P < 0.05 threshold.
Cox proportional hazards regression analysis
Multivariate Cox proportional hazards regression models were used to identify independent predictors of graft and patient survival. Recipient-specific variables included age, ethnicity (Black, White, Hispanic, or Other) BMI, gender, and pre-existing diabetes status. Donor and transplant-specific variables included the degree of HLA mismatch, cold ischemia time (CIT), and transplant era. Hazard ratios (HRs), and 95%CI were calculated for each covariate to quantify their associations with graft failure and patient mortality.
RESULTS
As outlined in Table 1, 62% of patients were within a healthy weight range at the time of transplantation. 13.6% were overweight, 11.1% Class 1 obese, 3.1% Class 2 obese, and 1% Class 3 obese. Figure 2 illustrates a steady rise in overweight and obese patients over time, with 2022 marking equal proportions of overweight and Class I obese patients (14.1%) and a 10-year high in Class II obesity (5%). Table 1 also summarizes recipient and donor characteristics by BMI. Overweight and obese patients of all classes were significantly less likely to have living donors compared to healthy-weight individuals (P < 0.05), with the lowest rates among Class 2 obese patients (34.4% vs 42.8% for healthy-weight, P < 0.001). CIT were significantly higher for Class 2 and 3 obese patients (11.6- and 13.1-hours vs 10.2 hours for healthy-weight, P < 0.001). Obese patients were more likely to be male (66.7% in Class 3, 61.8% in Class 2, 63.6% in Class 1, vs 57.5% in healthy weight, P < 0.05). Overweight and Obese patients were more likely to be younger, with a 12-year average age for healthy weight compared to 11, 9, 11, and 10 years for overweight, Class 1, 2, and 3 obesity, respectively. Non-White patients, mainly Black and Hispanic patients, were overrepresented in overweight and obese groups, with Class 3 obesity showing the highest proportion of Black patients (26.2% vs 17.9%, P < 0.001). No significant differences were found between BMI groups in donor distance from the transplant center, Kidney Donor Profile Index (KDPI), donor sex, or DGF rates. There were also no differences in 1-year graft or patient survival across BMI categories. However, significant differences were observed in long-term survival metrics. Underweight patients had significantly lower 10-year patient survival (81.3%) compared to healthy-weight patients (85.5%, P = 0.003), overweight (86.7%, P = 0.003), and Class 1 obese individuals (86.1%, P = 0.001) Class 2 obese patients had the lowest 10-year patient survival (78.9%) compared to healthy-weight (85.5%, P < 0.001) and overweight individuals (86.7%, P < 0.001). Similarly, Class 3 obese patients had significantly reduced 10-year survival (79.9%) compared to healthy-weight and overweight patients (P < 0.05) Kaplan-Meier analysis for graft survival and patient survival is depicted in Figure 3 and Figure 4. Log-rank testing, displayed in Table 2, revealed significantly lower graft survival in Class 2 (P = 0.013) and 3 (0.022) obese patients compared to healthy-weight individuals. This was similar when graft survival of Class 2 (P = 0.033) and Class 3 (0.033) obese patients were compared to Class 1 obese individuals. Similarly, significant differences in patient survival were observed comparing healthy weight to Class 2 (P = 0.03) and Class 3 (P < 0.001) obese groups over the study period. Underweight individuals had significantly lower graft survival than both healthy-weight individuals (P = 0.007) and overweight individuals (P = 0.026) in terms of patient survival (Table 3). No differences were seen between healthy-weight individuals and overweight (P = 0.246) and Class 1 Obese individuals (P = 0.796) in terms of graft survival. No differences were seen comparing healthy-weight individuals and overweight (P = 0.845) or Class 1 Obese individuals (P = 0.179) in terms of patient survival. Data from Cox regression identified key predictors of graft survival, this is depicted in Table 4. Each BMI point increase raised graft failure risk by 2.0% (95%CI: 1.015–1.025, P < 0.001). Older age increased graft failure risk by 4.1% per year (95%CI: 1.035–1.047, P < 0.001). Female recipients had a 14.5% higher risk of graft failure compared to males (95%CI: 1.090–1.204, P < 0.001). Later transplant eras reduced graft failure risk by 14.0% (95%CI: 0.845–0.875, P < 0.001). HLA mismatches and cold ischemic time also negatively impacted survival, increasing risk by 8.8% per mismatch unit (95%CI: 1.069–1.107, P < 0.001) and 1.1% per hour (95%CI: 1.008–1.013, P < 0.001), respectively. Ethnicity was not significant (95%CI: 0.998–1.002, P = 0.887). The impact of recipient diabetes was also negligible (95%CI: 1.000–1.000, P = 0.059). For patient survival, significant predictors included older age (4.9% higher mortality risk per year; 95%CI: 1.036–1.062, P < 0.001) and female gender (20.1% higher mortality risk compared to males; 95%CI: 1.087–1.327, P < 0.001). BMI category increases mortality risk by 1.8% (95%CI: 1.008–1.029, P < 0.001). Later transplant eras improved survival (95%CI: 0.871–0.940, P < 0.001). HLA mismatches and ischemic time further elevated risk by 11.9% per mismatch unit (95%CI: 1.080–1.160, P < 0.001) and 1.3% per hour (95%CI: 1.008–1.018, P < 0.001), respectively. Diabetes (95%CI: 1.000–1.001, P = 0.155) and ethnicity (95%CI: 0.999–1.003, P = 0.370) were not significant predictors.
Figure 3 Kaplan-Meier estimates of kidney allograft survival between body mass index classes.
Correlate statistically significant differences in graft survival between body mass index classes using the log-rank testing in Table 2. BMI: Body mass index.
Figure 4 Kaplan–Meier estimates of kidney allograft recipient survival between the different body mass index classes.
Correlate statistically significant differences in patient survival between body mass index classes using the log-rank testing in Table 2.
Table 1 Recipient and donor characteristics of pediatric kidney transplants separated by body mass index class, n (%).
Table 4 Predictors of graft and patient survival based on cox regression analysis.
Predictor
Hazard ratio
95%CI
P value
BMI (per point)
1.020
1.015–1.025
< 0.001
Age (per year)
1.041
1.035–1.047
< 0.001
Female gender (vs male)
1.145
1.090–1.204
< 0.001
Transplant era (per later era)
0.860
0.845–0.875
< 0.001
HLA mismatch (per unit)
1.088
1.069–1.107
< 0.001
Cold ischemia time (per hour)
1.011
1.008–1.013
< 0.001
Ethnicity
1.000
0.998–1.002
0.887
Presence of diabetes
1.000
1.000–1.000
0.059
BMI (per point)
1.049
1.036–1.062
< 0.001
Age (per year)
1.201
1.087–1.327
< 0.001
Female gender (vs male)
1.018
1.008–1.029
< 0.001
Transplant era (per later era)
0.905
0.871–0.940
< 0.001
HLA mismatch (per unit)
1.119
1.080–1.160
< 0.001
Cold ischemia time (per hour)
1.013
1.008–1.018
< 0.001
Ethnicity
1.001
0.999–1.003
0.370
Presence of diabetes
1.000
1.000–1.001
0.155
DISCUSSION
This study highlights the impact of obesity on pediatric KT outcomes, providing insights into disparities across BMI categories. Our findings align with previous research suggesting that elevated BMI, particularly in Class 2 and 3 obesity, is associated with poorer transplant outcomes. Cox regression analysis identified obesity as an independent risk factor for both patient and graft survival, with each BMI point increase associated with a 2.0% higher hazard for graft failure (95%CI: 1.015-1.025, P < 0.001). While there were no significant differences in 1-year survival rates across BMI categories, underweight, Class 2, and Class 3 obese recipients demonstrated significantly lower 5- and 10-year survival rates compared to healthy-weight, overweight, and Class 1 obese individuals. These findings emphasize the risks associated with being underweight and with severe obesity. Longer CIT, a procedural factor in transplants, was more common amongst obese recipients, particularly those in Class 2 and 3 obesity. CIT independently increased the hazard of graft failure by 1.1% and patient mortality by 1.3% per additional hour. This is supported by previous findings that link prolonged CIT to worse graft and patient survival[14]. Living donor transplants, which are associated with shorter CIT and better survival, were significantly less common amongst overweight and obese recipients compared to their healthy counterparts[15,16]. This disparity is partially explained by parental obesity, as parents, who are the most likely living donors for their children, face BMI restrictions that could disqualify them from donating. Childhood obesity is directly linked to parental obesity, with children of obese parents being 3-6 times more likely to become obese themselves, and children with two obese parents are 10-12 times more likely[17]. The reasons for this are multifaceted, including genetic factors associated with fat storage and appetite, environmental factors including eating habits and lifestyles, alongside societal and familial pressures[17]. Although there is no national cut-off to be a kidney donor, most transplant centers will reject anyone over a BMI of 35, with some transplant centers rejecting anyone with a BMI of 30 and over. Addressing parental obesity through family-centered weight management programs before transplant could mitigate this barrier, increasing the availability of living donor kidneys for obese children. Obese pediatric recipients were more likely to be from non-White racial backgrounds, particularly Black and Hispanic populations, with Class 2 obesity showing the highest proportion of Black patients. Notably, ethnicity was not a significant predictor of either graft or patient survival after adjusting for other variables, including BMI, HLA mismatch, CIT, and transplant era. This finding supports the growing body of evidence that disparities in transplant outcomes among ethnic groups are driven by modifiable factors, including healthcare access, nutrition, and socioeconomic barriers rather than intrinsic biological differences[12]. Prior studies have shown no significant weight differences between Black and White preschool children when adjusting for prenatal, perinatal, and early life factors[18]. These results highlight the importance of addressing modifiable systemic barriers in improving transplant outcomes. Recipient age, gender, and transplant era also emerged as significant predictors of transplant outcomes. Older recipients experienced a 4.1% increased risk of graft failure and a 4.9% increased risk of mortality for each additional year of age, likely reflecting the cumulative impact of comorbidities, prolonged dialysis exposure, and immunological factors. Interestingly, male recipients, despite being more likely to be obese, demonstrated a 14.5% lower hazard of graft failure compared to females and 20.5 Lower hazard of mortality. This gender advantage may result from differences in fat distribution, hormones, immune responses, and medical treatment. In a majority of high and upper-middle-income countries, boys are more often obese, influenced by biological factors including leptin levels and societal pressures on girls to maintain a lower body weight[19]. Successive transplant eras were associated with significant improvements in survival, with each era reducing the hazard of graft failure by 14.0% and mortality by 9.5%. This is also multifaceted, impacted by advances in surgical techniques that have minimized perioperative complications, improved immunosuppressive regimens with more efficacious medications, and changes in pediatric allocation policy. The 2014 revision to the Kidney Allocation System introduced a system in which pediatric candidates received priority for all kidneys with a KDPI < 35%[20]. This change increased long-term survival outcomes by improving access to high-quality grafts[20]. Underweight recipients demonstrated lower survival rates compared to their normal-weight counterparts, highlighting the dual risks of obesity and malnutrition (Table 2). Previous studies have shown that underweight pediatric KT recipients face an increased risk of mortality secondary to cardiovascular disease when compared to normal-weight patients[21]. Large annual decreases in BMI have similarly shown increased mortality risk in children treated with KT[22,23]. Nutritional management should prioritize stabilizing BMI within a healthy range, recognizing that BMI serves as both an indicator of obesity and a marker of malnutrition or severe illness. No significant differences were observed between BMI groups in other important transplant metrics, such as donor distance from the transplant center, KDPI, donor sex, or rates of DGF. This suggests that the primary factors contributing to poorer outcomes in obese pediatric recipients are related more to recipient characteristics than donor variables. Additionally, although there was a trend in DGF rates, which increased proportionally with BMI, it was insignificant in our data, suggesting a potential area for future study within other datasets. Barriers to healthcare disproportionately impact low-income families and families of color, exacerbating disparities in transplant outcomes. Black Americans represent 31.9% of KT candidates but account for only 11.7% of living donors, a disparity driven by socioeconomic factors, healthcare mistrust, and lack of awareness about organ donation[24,25]. Financial assistance programs and culturally competent transplant teams are essential to building trust and reducing economic barriers, with pilot programs showing early success in increasing minority living donor transplants[25]. Public health initiatives targeting systemic inequalities, such as improving access to nutritious food and obesity prevention programs, could further address disparities in pediatric KT[26]. Despite the well-documented risks associated with obesity, particularly in the context of KT, this study suggests that with the proper management, obese pediatric patients can still achieve comparable outcomes to their healthy-weight counterparts in the short term. Given the comparable outcomes in overweight and Class 1 obese children in the setting of more obese and overweight children presenting for transplant than ever before, it seems as if the American transplant system has already adjusted to the trends in pediatric BMI. However, the long-term outlook, particularly for those in Class 2 and 3 obesity, remains concerning, with lower graft survival at 5 and 10 years. Structured pre-transplant interventions, such as comprehensive weight management programs, are an important addition to transplant teams. Programs integrating dietary counseling, behavioral therapy, and physical activity have successfully reduced BMI in pediatric population[27]. In severe cases, bariatric surgery has been shown to improve outcomes with obesity-related comorbidities, but there has not been extensive work on how it would impact pediatric transplant recipients[28]. Post-transplant interventions, including regular follow-ups with dietitians and physical activity programs, would allow for progress to be sustained over time, ultimately improving graft and patient survival. Emerging therapies like GLP-1 receptor agonists, which are effective in managing obesity and associated metabolic conditions, may offer a promising adjunct for improving outcomes in obese pediatric KT recipients. By promoting weight loss and improving insulin sensitivity, these agents could help optimize pre- and post-transplant health, potentially mitigating obesity-related risks. Further research is needed to explore their safety, efficacy, and long-term impact in this unique population. This study underscores the need for nuanced criteria in assessing and treating pediatric KT candidates with elevated BMI. While some transplant centers may view obesity as an absolute contraindication, our findings suggest that blanket restrictions on BMI alone may be too conservative. Instead, transplant centers should consider adopting a more individualized approach that considers a patient's overall health and management of the patient's obesity before and after transplant. Additionally, efforts to reduce barriers to living donor transplants for obese patients, including support for obese parents attempting child-parent donations, could reduce some of the risks faced by obese pediatric recipients.
This study, while comprehensive with an extensive number of transplants, has several limitations. First, the retrospective cohort design precludes the ability to establish causation between BMI and transplant outcomes. While the findings suggest associations between higher BMI categories and poorer graft and patient survival, the observational nature of the study means that unmeasured confounding factors may influence these outcomes. Additionally, the STAR/UNOS database lacks granular information about potential confounders, such as recipient hypertension, socioeconomic factors, and detailed metrics on obesity-related comorbidities, all of which could influence the data. Finally, the relatively small number of Class 3 obese patients may reduce the statistical power for this subgroup and limit the generalizability of the findings. The definition of Class 3 obesity (140% of the 95th percentile or BMI = 40) inherently encompasses a small fraction of the pediatric population, and a multi-center study focused on these patients would be needed to validate findings in this subgroup. Further prospective studies with more detailed clinical data are required to better understand causal relationships between BMI and outcomes in pediatric KT.
CONCLUSION
This study highlights the complex relationship between obesity and pediatric KT outcomes, emphasizing that Class 2 and 3 obesity are associated with significantly poorer long-term graft and patient survival. Cox regression analysis identified obesity and longer cold ischemic times as independent risk factors, with each BMI point increase associated with higher hazards for graft failure and mortality. However, recipients in the overweight and Class 1 obesity categories demonstrated comparable short-term and long-term outcomes to their healthy-weight counterparts, demonstrating the potential for clinical success with proper management. The disproportionate impact of obesity on Black and Hispanic children, alongside barriers to living donor transplants due to parental obesity, highlights the need for systemic interventions. Family-centered weight management programs to address both pediatric and parental obesity could expand the pool of eligible living donors and improve access to higher-quality organs. Pre- and post-transplant strategies, including dietary counseling, behavioral therapy, and physical activity programs, are important to optimize outcomes.
Footnotes
Provenance and peer review: Invited article; Externally peer reviewed.
Peer-review model: Single blind
Corresponding Author's Membership in Professional Societies: American College of Surgeons; American Society of Transplant Surgeons.
Specialty type: Transplantation
Country of origin: United States
Peer-review report’s classification
Scientific Quality: Grade B, Grade B, Grade C, Grade C
Novelty: Grade B, Grade B, Grade B, Grade B
Creativity or Innovation: Grade A, Grade A, Grade A, Grade C
Scientific Significance: Grade B, Grade B, Grade B, Grade B
P-Reviewer: Aktas G; Alsaidan AA; Wong E S-Editor: Liu H L-Editor: A P-Editor: Zhao YQ
Fouque D, Kalantar-Zadeh K, Kopple J, Cano N, Chauveau P, Cuppari L, Franch H, Guarnieri G, Ikizler TA, Kaysen G, Lindholm B, Massy Z, Mitch W, Pineda E, Stenvinkel P, Treviño-Becerra A, Wanner C. A proposed nomenclature and diagnostic criteria for protein-energy wasting in acute and chronic kidney disease.Kidney Int. 2008;73:391-398.
[RCA] [PubMed] [DOI] [Full Text][Cited in This Article: ][Cited by in Crossref: 1218][Cited by in RCA: 1290][Article Influence: 71.7][Reference Citation Analysis (0)]
Nielsen J, Hulman A, Narayan KMV, Cunningham SA. Body Mass Index Trajectories From Childhood to Adulthood and Age at Onset of Overweight and Obesity: The Influence of Parents' Weight Status.Am J Epidemiol. 2022;191:1877-1885.
[RCA] [PubMed] [DOI] [Full Text][Cited in This Article: ][Cited by in Crossref: 5][Reference Citation Analysis (0)]
Bonthuis M, Bakkaloglu SA, Vidal E, Baiko S, Braddon F, Errichiello C, Francisco T, Haffner D, Lahoche A, Leszczyńska B, Masalkiene J, Stojanovic J, Molchanova MS, Reusz G, Barba AR, Rosales A, Tegeltija S, Ylinen E, Zlatanova G, Harambat J, Jager KJ. Associations of longitudinal height and weight with clinical outcomes in pediatric kidney replacement therapy: results from the ESPN/ERA Registry.Pediatr Nephrol. 2023;38:3435-3443.
[RCA] [PubMed] [DOI] [Full Text][Cited in This Article: ][Cited by in Crossref: 1][Cited by in RCA: 2][Article Influence: 1.0][Reference Citation Analysis (0)]
Bonthuis M, van Stralen KJ, Verrina E, Groothoff JW, Alonso Melgar Á, Edefonti A, Fischbach M, Mendes P, Molchanova EA, Paripović D, Peco-Antic A, Printza N, Rees L, Rubik J, Stefanidis CJ, Sinha MD, Zagożdżon I, Jager KJ, Schaefer F. Underweight, overweight and obesity in paediatric dialysis and renal transplant patients.Nephrol Dial Transplant. 2013;28 Suppl 4:iv195-iv204.
[RCA] [PubMed] [DOI] [Full Text][Cited in This Article: ][Cited by in Crossref: 37][Cited by in RCA: 43][Article Influence: 3.6][Reference Citation Analysis (0)]
Boulware LE, Sudan DL, Strigo TS, Ephraim PL, Davenport CA, Pendergast JF, Pounds I, Riley JA, Falkovic M, Alkon A, Hill-Briggs F, Cabacungan AN, Barrett TM, Mohottige D, McElroy L, Diamantidis CJ, Ellis MJ. Transplant social worker and donor financial assistance to increase living donor kidney transplants among African Americans: The TALKS Study, a randomized comparative effectiveness trial.Am J Transplant. 2021;21:2175-2187.
[RCA] [PubMed] [DOI] [Full Text][Cited in This Article: ][Cited by in Crossref: 8][Cited by in RCA: 12][Article Influence: 3.0][Reference Citation Analysis (0)]
Dobrzycka M, Proczko-Stepaniak M, Kaska Ł, Wilczyński M, Dębska-Ślizień A, Kobiela J. Weight Loss After Bariatric Surgery in Morbidly Obese End-Stage Kidney Disease Patients as Preparation for Kidney Transplantation. Matched Pair Analysis in a High-Volume Bariatric and Transplant Center.Obes Surg. 2020;30:2708-2714.
[RCA] [PubMed] [DOI] [Full Text] [Full Text (PDF)][Cited in This Article: ][Cited by in Crossref: 11][Cited by in RCA: 14][Article Influence: 3.5][Reference Citation Analysis (0)]
