Chronic kidney disease following pediatric cardiac surgery: a systematic review and meta-analysis

Abstract

Background

Chronic kidney disease (CKD) is a potential long-term complication in children undergoing cardiac surgery. With improved survival rates in this population, attention has shifted toward long-term outcomes, yet the true burden of CKD remains unclear due to limited data.

Objectives

To determine the pooled prevalence of chronic kidney disease among pediatric patients with a history of cardiac surgery.

Materials and methods

A systematic literature search was conducted in PubMed, Scopus, and Web of Science from inception to March 1, 2025. Eligible studies included those reporting CKD prevalence in patients under 18 years of age who had undergone any type of cardiac surgery. We performed this systematic review and meta-analysis following PRISMA guidelines and Cochrane Collaboration recommendations using a random-effects model. Pooled prevalence estimates were calculated with 95% confidence intervals (95% CI).

Results

Data from five prospective studies involving 1002 pediatric patients were included. The studies were published between 2016 and 2022 and conducted in Canada, France, the United States, and Belgium. The pooled prevalence of CKD was 16% (95% CI: 9.0–26.0%), with moderate heterogeneity across studies (I² = 49.5%, p = 0.09). Sensitivity analysis confirmed the stability of the pooled estimate.

Conclusions

The findings of this analysis highlight the need for long-term renal monitoring in this population, although further high-quality studies with standardized definitions and extended follow-up are warranted to confirm and refine these estimates.

Supplementary Information

The online version contains supplementary material available at https://doi.org/10.1186/s12887-026-06687-9.

Introduction

Congenital heart defects (CHDs) affect approximately 1.3 million newborns every year, worldwide, over 70% of whom require surgical or medical intervention within their first year of life [1]. Advances in pediatric cardiology and cardiac surgery have significantly enhanced survival rates, resulting in a growing number of children with CHD transitioning into adulthood [2].

Cardiac surgery-associated acute kidney injury (AKI) is a major complication observed in children undergoing cardiac surgery with an estimated incidence ranging between 30% and 60% [3]. AKI arises through several interrelated mechanisms. These include systemic inflammation induced by cardiopulmonary bypass, ischemia-reperfusion injury, oxidative stress, and the formation of micro-emboli [4]. The clinical significance of AKI after cardiac surgery extends beyond the immediate postoperative period. It is noteworthy that affected children are more prone to experience adverse long-term outcomes (e.g. chronic kidney disease (CKD)) [5]. Additionally, systemic inflammatory responses induced by cardiac surgery can contribute to tubular cell injury and promote the progression of AKI to CKD [6]. In certain cases, unresolved kidney injury during AKI initiates fibrotic processes, leading to structural remodeling and sustained impairment of kidney function inducing CKD [7]. Furthermore, Hemodynamic instability, including fluctuations in blood pressure and perfusion, further compounds kidney stress and contributes to the severity of kidney injury [8].

Given the improved survival rates following pediatric cardiac surgery, attention has increasingly shifted toward understanding and addressing long-term complications in this vulnerable population. One significant concern is the development of CKD, which can adversely affect long-term health outcomes. Without timely intervention, CKD can progress to end-stage kidney disease, a condition that severely limits patients’ functional capacity, social participation, and survival in the absence of dialysis or transplantation [9]. Early identification and intervention are essential for mitigating kidney damage and optimizing patient care. To date, data on the prevalence of CKD in this population remain fragmented and inconsistent. This systematic review and meta-analysis aims to synthesize the existing evidence to determine the pooled prevalence of CKD among children who have undergone cardiac surgery, thereby informing clinical surveillance strategies and guiding future research and prevention efforts.

Methods

This systematic review and meta-analysis was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines and recommendations from the Cochrane Handbook for Systematic Reviews [10]. The research protocol was also registered in the PROSPERO database under the ID 1,033,253.

A comprehensive search was carried out across electronic databases of PubMed, Scopus, and Web of Science to obtain records from inception until March 1, 2025, without any language or publication data restrictions. The search strategy incorporated various keywords such as “open heart surgery”, “chronic kidney disease”, “Pediatric”, and “prevalence”. Mesh terms and the synonyms of each term was also included (supplementary file1).

Study selection and eligibility criteria

Studies with the following criteria were selected for inclusion: (1) Patients under 18 years old with a history of any cardiac surgery with whether vascular or structural heart disease or congenital heart disease. (2) Studies that reported the prevalence of CKD. Studies without quantitative data on the prevalence of CKD, editorials, conference abstracts, reviews, or studies with non-human samples were excluded. Two independent reviewers (A.H, and M.M) reviewed the titles and abstracts of articles, and the remained articles were assessed in full-text by the two reviewers (A.H, M.M). in case of any discrepancies, they consulted with a third reviewer (H.B).

Quality assessment

Two reviewers (A.H, and M.M) independently assessed the quality of included articles using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist designed for observational research. In case of any disagreements, they discussed it over with a third reviewer (H.B) to reach a conclusion. To ensure consistency in long-term outcome assessment, we included only studies with a minimum follow-up duration of approximately five years.

Data extraction

A data extraction checklist was developed, including parameters such as the first author’s name, country, year of publication, study design, sample size, follow-up period, definition of CKD, prevalence of CKD, type of surgery and age of participants. Two authors (M.M, A.H) independently extracted these variables from the included studies.

Statistical analysis

To calculate the pooled prevalence of CKD among pediatrics with a history of cardiac surgery, we used a random-effects model to account for variability across the five included studies. The analyses were performed using Comprehensive Meta-Analysis (CMA) software, version 4.0. Results are presented with 95% confidence intervals (CI). Study heterogeneity was evaluated using both the I² statistics and Cochran’s Q test. To evaluate the stability of the finding, sensitivity analyses was performed by sequentially removing each study. Publication bias was examined through funnel plot assessment, complemented by Egger’s and Begg’s tests to detect asymmetry.

Results

Study selection

The initial search identified a total of 280 records from databases and registers. After removing 51 duplicates, 229 records remained for title and abstract screening. Of these, 170 records were excluded based on relevance and eligibility criteria. The full texts of 59 articles were assessed for eligibility.

Following full-text review, 55 articles were excluded for reasons including irrelevant outcomes and quality assessment.

Ultimately, 5 studies met the inclusion criteria and were included in the final qualitative and quantitative synthesis (Figure 1).

Fig. 1.

PRISMA flowchart indicating the study selection process

Study characteristics

Our search results from inception to March 1, 2025 yielded to 5 studies from 2016 to 2022, including a total number of 1002 patients were assessed. Studies were conducted in Canada [11], France [12], United States [5, 13], and Belgium [3]. All 5 studies were designed prospectively, with nearly five years of follow-up and the definition of CKD was mainly based on GFR and albumin to creatinine values (Table 1).

Table 1.

Characteristics of the included studies

Author (year/ country)	study design	sample size	follow-up period (year)	definition of CKD	Prevalence of CKD (%)	age	Type of surgery
L Huynnh (2020/ Canada)	Prospective	58	5 to 7	eGFR < 90 mL/min/ 1.73 m2 or ACR ≥ 3 mg/mmol.	17	median (IQR) age of 10 days	congenital heart disease surgery
M Bojan (2020/ France)	Prospective	115		Kdigo 2012	0	Average: 4.3+_2.1 years	congenital heart disease surgery
J Greenberg (2016/ United states)	Prospective	131	5	An eGFR less than 90 mL/min/1.73 m2 or microalbuminuria	18	Average: 31.9 (6.0-58.6) months	cardiac surgery with cardiopulmonary bypass
J Eynde (2022/ Belgium)	Prospective	571	5	eGFR < 90 mL/min per 1.73 m² or eGFR 90 mL/min per 1.73 m² to 100 mL/ min per 1.73 m² with laboratory/ultrasound abnormali- ties	27.3	79 (IQR, 9.0- 230 days)	cardiac surgery with extra- corporeal circulation
N Madsen (2017/ United States)	Prospective	127	4.9	CKD development was assessed in all subjects by eGFR from the Pottel formula using sCr measurements in the LABKA database. restricted the outcome de nition to stages 2 to 5 exclusively.	12	Children under 14 years	congenital heart disease surgery

CKD Chronic Kidney Disease, eGFR Estimated Glomerular Filtration Rate, ACR Albumin-to-Creatinine Ratio, sCr Serum Creatinine, IQR Interquartile Range, mL/min/1.73 m²: Milliliters per minute per 1.73 square meters (normalized GFR unit)

All included studies were of high quality, as assessed by their JBI appraisal checklists’ scores (supplementary file 2), except for one study that scored 2. This study had a follow-up period of only 1 year, which is quite short to measure CKD prevalence [14].

Results of meta-analysis

The pooled prevalence of CKD among pediatrics with a history of cardiac surgery was 16% (95% CI: 9.0–26.0%). (Figure 2). The results showed moderate heterogeneity among studies (I² = 49.5%, P = 0.09). The trim and fill analysis did not identify any missing studies on either side of funnel plot (Figure 3). Assessment of publication bias using Egger’s test indicated potential asymmetry (P = 0.01), while Begg’s test did not show significant bias (P = 0.32). The prediction interval analysis demonstrated that the true effect size in 95% of all comparable populations ranges from 2.0 to 60.0% (Figure 4). The sensitivity analysis showed no significant change in the pooled estimate when any individual study was removed (Figure 5).

Fig. 2.

The pooled forest plot of the study population

Fig. 3.

The funnel plot representing publication bias

Fig. 4.

Prediction interval analysis

Fig. 5.

Sensitivity analysis of all included studies

Discussion

Early identification and management of CKD during childhood is essential because pediatric risk factors such as kidney dysfunction are strongly associated with adverse cardiovascular outcomes in adulthood [15, 16]. This concern is particularly important in children with congenital heart disease, given their elevated risk for long-term cardiac complications [17, 18]. To the best of our knowledge, no previous meta-analysis has synthesized data from original studies to determine the pooled prevalence of CKD in children following cardiac surgery and despite the recognized risk, there remains a scarcity of research addressing the long-term renal outcomes following cardiac surgery [19, 20]. In this systematic review and meta-analysis, we aimed to address this gap by evaluating the prevalence of CKD in pediatric patients post–cardiac surgery. Our systematic search identified five eligible studies for inclusion and findings demonstrated that 16% of children who had undergone cardiac surgery developed CKD after a mean of 5 years’ follow-up.

Based on a registry system in the United States, the overall prevalence of CKD in children and adolescents is reported to be approximately 0.27% [21]. In comparison, our meta-analysis found a much higher CKD prevalence of 16% among children who had undergone cardiac surgery, nearly 60 times higher than that of the general pediatric population. This striking difference highlights that these children are at significantly higher risk for developing CKD. It is essential to identify the causes of this increased risk and to explore possible preventive strategies.

Among all included studies, the prevalence of CKD ranged between 12 and 27.3%. The study by Eynde et al., which included the largest sample size (571 patients), reported the highest CKD prevalence (27.3%) [3]. However, the results of the study by Bojan et al. reported no cases of CKD in the follow-up of patients with cardiac surgery [12]. This controversial result may be because of difference in its study design. Bojan’s study only included patients attending the outpatient cardiac clinic, excluding those with hospital admissions for decompensated CHD. Unlike the other studies, they did not perform active CKD identification and systematic follow-up with SCr, eGFR, or proteinuria measurements. Subsequently, this likely excluded sicker patient, including those at higher risk for CKD.

In the studies included in our meta-analysis, the methods used for CKD screening were primarily estimated glomerular filtration rate (eGFR) and the urine albumin-to-creatinine ratio (ACR) [3, 5, 11–13] These methods are consistent with the KDIGO guidelines, which recommend the use of eGFR to assess kidney function and ACR to screen for albuminuria, both of which are important biomarkers in the diagnosis and staging of CKD which are consistent with KDIGO guidelines [22]. Four out of the five studies in our analysis defined CKD as stage 2 or higher, based on eGFR values below 90 mL/min/1.73 m², which is a commonly used threshold for identifying CKD. These studies followed the KDIGO guidelines for CKD staging, where stages 1 to 5 are based on eGFR levels and the presence of proteinuria or albuminuria. The studies that used these definitions included eGFR values under 90 mL/min/1.73 m², which corresponds to CKD stages 2 or higher. These definitions are consistent with international standards for diagnosing CKD and are widely accepted in clinical practice and research [3, 5, 11, 13]. However, one of the included studies, by Bojan et al. [12]. did not clearly address CKD staging. While this study included an assessment of kidney function, it did not provide sufficient details on the specific stage of CKD based on eGFR or ACR, which limits the ability to classify the severity of CKD in the patient population. This lack of clear CKD staging is a significant limitation, as staging provides crucial information on the progression of kidney disease, helps guide clinical management, and informs prognosis.

This variation in the reporting of CKD staging is one of the reasons why our meta-analysis was unable to offer a comprehensive analysis of the distribution of CKD stages. Without uniform staging across studies, it is difficult to fully interpret the severity of CKD in this population. Therefore, we recommend that future research standardize CKD staging across studies, using clearly defined eGFR and albuminuria thresholds, to allow for more precise comparisons and to enhance the clinical relevance of the findings. Reporting CKD stages in a consistent manner is essential for understanding the full scope of CKD and its long-term effects, especially in high-risk populations such as children undergoing cardiac surgery.

In present meta-analysis, we attempted to assess publication bias using both visual inspection of funnel plots and statistical methods such as Egger’s and Begg’s tests. In this study, we had mixed publication bias results. While Egger’s test suggested possible bias, this was not supported by Begg’s test or the Trim and Fill method, which found no imputed studies, indicating that the observed funnel plot asymmetry may not reflect true bias.

Despite the strengths and importance of this meta-analysis, there were several limitations that should be considered. First, the number of included studies was relatively small, and most had small sample sizes, which may limit the generalizability of the findings and the reliability of bias tests. In light of these limitations, future research should focus on large-scale, multicenter prospective studies with standardized diagnostic criteria and longer follow-up durations to more accurately assess the long-term renal outcomes in children after cardiac surgery. Investigating modifiable perioperative and postoperative risk factors, including blood pressure management and nephrotoxic exposures, may help identify targets for preventive interventions. Additionally, future research should focus on exploring and reporting specific risk factors such as surgical complexity, cardiopulmonary bypass duration, ECMO exposure, CHD severity, cardiovascular morbidity, nephrotoxic medication exposure, and AKI incidence, which were inconsistently reported or absent across the included studies. This limitation prevented meaningful subgroup analyses and likely contributed to the residual heterogeneity observed. Future research should prioritize standardized and comprehensive reporting of these key clinical factors, alongside uniform CKD definitions and long-term follow-up, to allow more robust risk-factor evaluation and a clearer understanding of modifiable determinants of renal outcomes after pediatric cardiac surgery. Furthermore, it would be valuable to assess the effectiveness of early screening and intervention programs in reducing CKD progression and improving long-term cardiovascular and kidney health in this high-risk population. Also, the most included studies did not specify the type of cardiac surgery (e.g., open-heart, catheter-based, transplant) or patient factors (such as syndromes or preexisting renal disease), which limits interpretation of CKD prevalence across different populations.

Conclusion

This meta-analysis found that 16% of children who underwent cardiac surgery developed CKD after an average of five years, a prevalence markedly higher than in the general pediatric population. The findings highlight the long-term kidney risks in this vulnerable group and emphasize the need for timely post-operative kidney monitoring, and larger prospective studies.

Supplementary Information

Supplementary Material 1. ^{(13.2KB, docx)}

Supplementary Material 2. ^{(18.6KB, docx)}

Authors’ contributions

Hamidreza Badeli and Azita Tangestani nejad conceived the idea for the article. Afagh Hassanzadeh-Rad and Mahsa Motiei conducted the literature search, data extraction, and data analysis. Mahsa Motiei drafted the manuscript. All authors reviewed and revised the final version of the article.

Funding

No funding was received for conducting this study.

Data availability

All data generated or analyzed during this study are included in this published article and its supplementary information files.

Declarations

Ethics approval and consent to participate

Ethics approval and consent to participate were not required for this study, as it is based on previously published data.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.