Kidney transplant (KT) is considered the treatment of choice for kidney failure (KF) in children and teenagers, offering a chance at improved quality of life and extended survival [1,2]. This procedure is performed globally, although unevenly, because of its costs and complexity [3]. Outcomes of KT are historically improving, allowing great short-term survival of graft However, challenges with long-term outcomes persist [4–6], especially in low- and low-middle-income countries. In low resource settings, beyond medical issues, there are difficulties with family educational level, housing and sanitation conditions, food security, socioeconomic vulnerability, and health services structure [7]. In 2023, Brazil recorded a substantial transplantation activity, with more than 6000 KT procedures performed; pediatric KT accounts for about 5% of these numbers. Despite this, the rate of KT in Brazil is about 30 transplants per million people, ranking lower than in some other upper-middle-income countries [8]. Such disparities are more pronounced when examining regional differences within the country. Previous multicentric studies in our country have described pediatric kidney transplantation in Brazil [9,10]. Nevertheless, there are great inequalities of this practice: children enrolled in some regions are less likely to receive a KT, and better economic and social indicators of a region correlate with better KT numbers [11].

These regional disparities raise crucial questions about equity in healthcare access and the quality of care provided to children and adolescents with kidney failure across different Brazilian states. In this study, we aimed to describe the clinical and epidemiological characteristics of pediatric kidney transplantation and its outcomes in the state of Bahia. This is a region where the majority of the population is considered Black, and with an illiteracy rate of around 12%, just over 50% of the population have access to the sewage system, and where the nominal monthly household income per capita is around US$ 230 in the year of 2024 [12]. By focusing on this locality, the study seeks to illuminate the broader implications of regional disparities on pediatric KT outcomes in Brazil. We also performed an exploratory analysis of predictors of graft and patient survival within this cohort, providing insights that may guide future interventions and policy adjustments to improve the equity and effectiveness of kidney transplantation across diverse regions. In essence, our research question was whether KT in our location, a low-resource setting, is feasible and whether it has similar outcomes as what’s described in the literature.

The present study demonstrates that patient and graft survival rates at a single Brazilian center were comparable to those reported by most transplantation cohorts. Clinical and demographic characteristics were generally similar; however, some differences were noted, including a higher proportion of Black recipients, a greater prevalence of kidney failure (KF) with unknown etiology, a longer waiting times for transplantation and a longer period on dialysis compared to most previously published studies [10,14–18]_. Furthermore, our exploratory analysis identified an adverse association between DGF and graft survival. No significant predictors of patient survival were found. The predominance of black patients is in line with demographic data from our state in Brazil [12]. This is quite different from other studies from Brazil [12,18] and other countries [5,17,19,20]. Of note, the collaborative Brazilian registry did not mention the race of the patients [10]. Race has been identified as a predictor of transplant outcomes since a huge number of studies have described that black patients have a higher risk of graft failure, either among adults or pediatric patients [17,21–23]. The black race can be considered a marker of a combination of social determinants of health capable of justifying worse outcomes, as low socioeconomic status, poor access to better quality health services, food, and job insecurity. Previous literature data have already shown that black patients have worse graft survival even after adjusting for various sociodemographic and even clinical characteristics [24]. Hence, immunological, biological, and genetic factors that are not yet fully understood may also account for poor outcomes in Black patients. Over the last decade, for instance, the discovery of a higher prevalence of APOL1 risk variants in individuals with recent African ancestry has illuminated some questions about this racial disparity [25]. Our study was not able to assess variables related to socioeconomic status individually and did not aim to evaluate APOL1 gene expression. Nevertheless, the great majority of black patients in our cohort may be a possible, albeit partial, explanation for our finding of slightly worse graft survival compared to other published cohorts.

Our study population has a similar etiology of KF and sex distribution of previously described transplanted children[10,17]. The frequency of patients with unknown etiology of renal failure, however, was much higher than described in other contexts [17,26]; this is generally common in low-resource settings, when early and primary diagnosis of chronic kidney disease can be quite challenging. This explanation is endorsed by a previous study that revealed a higher rate of unknown primary diagnosis in the poorest regions of Brazil (up to 46.3%) and a minimum time between primary chronic kidney disease diagnosis and initiation of renal replacement therapy in these regions (less than 1 month) [27].

We have a substantial number of preemptive transplants, greater than some other Brazilian centers[10,14,15]. Time in dialysis before KT is higher than our waiting time, revealing that our children and adolescents remain on dialysis for some time before they are enrolled in the National Transplant System or even without being referred to a transplantation center for preparation. In agreement with Brazilian cohorts [10,15,28], deceased donor KT was far more frequent than living donor KT in our population. In other countries, the rate of transplants with a living donor exceeds that with a deceased donor, to a greater or lesser extent [16,17,19]. This divergence may reflect discrepancies between living organ donation policies between countries, in combination with differences in the structure of organ procurement systems from deceased donors. In Brazil, there are legal restrictions on unrelated kidney donation, and transplantation with a living donor accounted for less than 15% of all kidney transplant activity in the country in 2023 [8].

Furthermore, DGF was very prevalent in our study population, even with CIT shorter than 24 hours, differently from what has been reported in other pediatric Brazilian cohorts [10,15], but following rates presented in a multicenter study of adults in our country [29]. Poor donor maintenance, recipient dialysis adequacy, or immunological factors (as HLA mismatches or preformed HLA antibodies) may account for this high prevalence; unfortunately, these features were not captured in our study.

Use of ATG was very frequent in our population, and this may be related to the unavailability of basiliximab in our center since 2017. This augmented use of induction with lymphocyte-depleting agents may be at least in part responsible for our high incidence of CMV infection (whether viremia or disease). On the other hand, we had a relatively high frequency of patients with presumed or confirmed rejection, similar to what’s described in the North American registry [17], and higher than reported in the Brazilian study [10].

Patient survival was slightly inferior to what has been described in pediatric Brazilian studies [10,14]; however, it was within what would be expected for data relating specifically to South America in a recently published metanalysis [30]. As for graft survival, we have worse outcomes mainly at 1-year post-transplant, at least partly due to our high rates of vascular thrombosis. Overall graft survival at 3, 5, and 10 years was also lower than that described in the meta-analysis, both for pooled global data and specific to South America [30].

Our state is one of the poorest in the country, with low per capita income and low educational levels [12]. Besides, our center has been performing pediatric KT for about 15 years, and probably our team expertise is still evolving. Innovations related to the diagnosis and treatment of some complications have been available for less time than in other specialized centers in Brazil or around the world. These factors may also contribute to our outcomes.

In our exploratory analysis of predictors of graft survival, we found that DGF had inferior outcomes; this is in concordance with what’s now known for the transplantation community, both for adults and children [17,29,31,32]. In our cohort, DGF was strongly correlated with worst graft survivals. Regarding to the predictors of patient survival, we found no predictors of mortality, possibly because of our small sample size and a small number of deaths. To our knowledge, there are few studies that correlate predictors of patient survival rate in pediatric population. NAPRTCS reports better patient survival with living donor kidney transplants and with recipients > 2 years old.

This study has some limitations. The retrospective nature may lead tosome inconsistent information throughout all the follow-up. Particularly, data about race may have not been self-declared in all patients. Also, our study population only included patients attending in our public health system. We had little missing data. However, due to the frequent unavailability of some data in the medical records, some variables were not included in the study, as number of HLA compatibilities or social and economic features, In addition, we had a small number of deaths; thus, our analysis of predictors of patient survival must be confirmed in a larger population. These findings may have some influence of race or other social and clinical characteristics, not captured in this study, such as biochemical data or dialysis adequacy before KT.

Despite the limitations, this is the first report from a peripheral Brazilian region, showing that kidney transplant is still a good and feasible option for KF treatment regionally, allowing the survival of patients with this complex and severe disease. Based on our findings, we reinforce the need for early referral to transplantation centers and special attention to small children. We urge for better care of pediatric patients with chronic kidney disease in our location and in other low resource settings, with proper elucidation of primary disease, early diagnosis and expeditious preparation of the potential recipient of kidney transplant. Improving dialysis adequacy, encouraging preemptive transplantation, and optimizing potential donor maintenance can also mitigate the occurrence of DGF, allowing better outcomes. Future research is demanded for clarifying the impact of other predictors in graft and patient survival in pediatric kidney transplants. Remarkably, multicentric studies may be more promising, given the possibility of bigger sample sizes, once pediatric chronic kidney disease is a rare disease.