Joo Hoon Lee

A paucity of literature exists on the development of predictive tools for the decline of kidney function in pediatric chronic kidney disease (CKD). The objective of this study is to develop and internally validate a tool for the short-term prediction of a kidney function decline in pediatric patients with CKD. A total of 539 patients participating in the KNOW-PedCKD (KoreaN cohort study for Outcomes in patients With Pediatric Chronic Kidney Disease) were evaluated for 48 variables related to sociodemographic characteristics, laboratory data, and treatment use. These variables were assessed as potential predictors of a kidney function decline in pediatric patients with CKD using a range of machine learning algorithms. The models demonstrated strong predictive performances in identifying kidney function decline, defined as an estimated glomerular filtration rate (eGFR) decline of ≥20%, which includes progression to kidney replacement therapy or death. The random forest and XGBoost models demonstrated the best performance in predicting eGFR outcomes at 1 year compared with 2 and 3 years, respectively. The spot urine protein-to-creatinine ratio was the most influential variable in the prediction model, followed by baseline eGFR and serum albumin, chloride, and hemoglobin levels. A tool for predicting kidney function decline in children with CKD over a short period of time was developed using potential predictors and machine learning methods in a large Korean pediatric CKD cohort.

Pediatric nephrotic syndrome is a clinical condition characterized by severe proteinuria, hypoalbuminemia, hyperlipidemia, and generalized edema, most commonly affecting children aged 2 and 6 years. Although standard oral steroid therapy is effective in managing most cases, relapses are common during childhood. Nephrotic syndrome presents significant challenges due to frequent relapses and the potential side effects of long-term drug therapy. In Korea, the absence of a unified national clinical guideline has led physicians to manage pediatric nephrotic syndrome based on diverse clinical guidelines and individual clinical judgment. To address this, the Korean Society of Pediatric Nephrology has developed an evidence-based guideline specifically tailored to the Korean healthcare system. This guideline provides recommendations for the diagnosis and management of steroid-sensitive nephrotic syndrome in children under the age of 18 years.

Pediatric nephrotic syndrome is a clinical condition characterized by severe proteinuria, hypoalbuminemia, hyperlipidemia, and generalized edema, most commonly affecting children aged 2 and 6 years. Although standard oral steroid therapy is effective in managing most cases, relapses are common during childhood. Nephrotic syndrome presents significant challenges due to frequent relapses and the potential side effects of long-term drug therapy. In Korea, the absence of a unified national clinical guideline has led physicians to manage pediatric nephrotic syndrome based on diverse clinical guidelines and individual clinical judgment. To address this, the Korean Society of Pediatric Nephrology has developed an evidence-based guideline specifically tailored to the Korean healthcare system. This guideline provides recommendations for the diagnosis and management of steroid-sensitive nephrotic syndrome in children under the age of 18 years.

Background: The natural course of chronic kidney disease (CKD) progression in children varies according to their underlying conditions. This study aims to identify different patterns of subsequent decline in kidney function and investigate factors associated with different patterns of estimated glomerular filtration rate (eGFR) trajectories. Methods: We analyzed data from the KNOW-Ped CKD (KoreaN cohort study for Outcomes in patients With Pediatric Chronic Kidney Disease), which is a longitudinal, prospective cohort study. A latent class linear mixed model was applied to identify the trajectory groups. Results: In a total of 287 patients, the median baseline eGFR (mL/min/1.73 m2) was 63.3, and the median age was 11.5 years. The eGFR decline rate was –1.54 during a 6.0-year follow-up. The eGFR trajectory over time was classified into four groups. Classes 1 (n = 103) and 2 (n = 11) had a slightly reduced eGFR at enrollment with a stable trend (ΔeGFR, –0.2/year) and a rapid decline eGFR over time (ΔeGFR, –10.5/year), respectively. Class 3 had a normal eGFR (n = 16), and class 4 had a moderately reduced eGFR (n = 157); both these chasses showed a linear decline in eGFR over time (ΔeGFR, –4.1 and –2.4/year). In comparison with classes 1 and 2, after adjusting for age, causes of primary renal disease, and baseline eGFR, nephrotic-range proteinuria was associated with a rapid decline in eGFR (odds ratio, 8.13). Conclusion: We identified four clinically relevant subgroups of kidney function trajectories in children with CKD. Most children showed a linear decline in eGFR; however, there are different patterns of eGFR trajectories.

Background: This study investigated the clinical characteristics and kidney outcomes of childhood-onset lupus nephritis (LN), and risk factors associated with prognosis. Methods: We enrolled 216 patients with histologically diagnosed LN during childhood. The Korean Society of Pediatric Nephrology organized a retrospective cohort study of childhood-onset LN in 13 major pediatric nephrology centers in South Korea. Results: The mean age at kidney biopsy was 13.2 ± 3.22 years. The main forms of presentation were nephrotic syndrome and/or hematuria in 152 patients (70.4%), and the most common histological finding was World Health Organization (WHO) class IV in 138 patients (63.9%), followed by WHO class III in 34 patients (15.7%). In the outcome analysis, the mean follow-up period of the patients was 7.8 ± 5.11 years. At last follow-up, 32 patients (14.8%) developed advanced chronic kidney disease (CKD). Male sex and failure to achieve remission at 12 months of treatment were significant risk factors for developing advanced CKD (hazard ratio of 2.57 and 2.29, respectively). Conclusion: Our study demonstrated the clinical characteristics and long-term outcomes of patients with childhood-onset LN. Male sex and failure to achieve remission in the first year of treatment were predictive of advanced CKD. Therefore, prompt awareness and close monitoring of these high-risk patients are needed, which may further improve the prognosis of children with LN.

The management of chronic kidney disease (CKD) includes nutritional interventions aimed at slowing disease progression and mitigating complications. This review examines various dietary approaches for CKD treatment, focusing on carbohydrate intake modulation, ketogenic diets, and plant-based diets. Standard guidelines recommend carbohydrate intake within 45% to 65% of total calories, but there is growing interest in reducing carbohydrate consumption to preserve kidney function. Low-carbohydrate diets (<25% of total calories) have shown benefits in glycemic control and weight reduction but may pose long-term adherence challenges. High-protein, low-carbohydrate diets are discouraged due to associations with hyperfiltration and CKD progression. Limiting fructose intake has been linked to reductions in blood pressure and uric acid levels. Intermittent fasting and ketogenic diets, which promote ketone body production and reduce inflammation, have shown promise in animal models and some human studies, particularly in autosomal dominant polycystic kidney disease, though more research is needed. Plantbased diets, such as the Mediterranean and DASH (Dietary Approaches to Stop Hypertension) diets, offer cardiovascular benefits and may reduce CKD risk but require careful management of potassium intake. Overall, dietary interventions should be individualized, considering potential risks like hyperkalemia and ensuring nutritional adequacy.

Hypertension is one of the most important complications of chronic kidney disease (CKD) as it exacerbates disease progression in children. The aim of this study is to identify characteristics and factors associated with hypertension in children with CKD. This is a cross-sectional study using baseline data from the 10-year ongoing cohort study named KNOW-PedCKD (Korean Cohort Study for Outcome in Patients with Pediatric Chronic Kidney Disease). We enrolled finally 378 patients aged <18 years at seven major pediatric nephrology centers in Republic of Korea. Blood pressure was measured and samples and clinical data were collected during the patients' annual hospital visits. We found that 30.7% of the patients had hypertension (n = 116); specifically, 16.4% (n = 62) had systolic hypertension, and 22.8% (n = 86) had diastolic hypertension. Multiple logistic regression analysis indicated that older age (odds ratio [OR], 1.13; p < 0.001), female sex (OR, 2.32; p = 0.002), a high left ventricular mass index (OR, 1.05; p < 0.001), and a high urine protein/creatinine ratio (OR, 1.12; p = 0.02) were significant associated factors for systolic or diastolic hypertension. This study analyzed the associated factors for hypertension in children with CKD. Hypertension is associated with various factors, including age, sex, heart status, and proteinuria. Therefore, clinicians should consider these factors during patient evaluations to improve health outcomes.

Background: As the coronavirus disease-2019 (COVID-19) pandemic continues, driven by the Omicron variant, infection rates in children have recently rapidly surged compared with previous years. We aimed to investigate the presentation of kidney involvement in children after Omicron variant severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Methods: We retrospectively reviewed the medical records of pediatric patients who presented with kidney disease with a temporal relationship with COVID-19 between January and August 2022 in a single tertiary center in Korea. Results: Fifteen children presented with kidney involvement after Omicron variant infection, with a median age of 10.6 (6.8–18.3) years. None of the patients exhibited severe respiratory symptoms apart from cough and sore throat. The median time from infection to renal symptom onset was 3 (0–49) days. Among 10 patients with underlying kidney disease, six had previously been diagnosed with nephrotic syndrome (NS) that relapsed after COVID-19 infection, two with immunoglobulin A nephropathy (IgAN) experienced transient gross hematuria (GHU) with or without acute kidney injury (AKI), and two with kidney transplantation presented with AKI. Of the five patients without underlying kidney disease, one patient had NS, and the other four patients had GHU and proteinuria (PU), of whom one was eventually diagnosed with Henoch Shönlein Purpura nephritis (HSPN), and one with rhabdomyolysis. The seven patients with NS (1 new-onset, 6 relapsed) had uneventful remission with corticosteroid therapy. Apart from one patient with new-onset HSPN, GHU and PU resolved spontaneously in all affected patients, and AKI also resolved with supportive care. Conclusions: Kidney involvement subsequent to Omicron variant COVID-19 exhibited various, but mostly mild manifestations in children.

Pleuroperitoneal communication (PPC) is a rare mechanical complication of peritoneal dialysis (PD), which causes dialysate to move from the peritoneal cavity to the pleural cavity, resulting in pleural effusion. Typically, PPC is discovered through pleural effusion in PD patients who are not in volume overload status. A unique characteristic of the pleural effusion caused by PPC is that it is not resolved by increasing ultrafiltration by dialysis. In this report, we present a 7-year-old girl with PD after birth with the history of various infectious PD-related complications, presenting with fever ongoing for 6 months. PPC-associated pleuritis was suspected as the cause of fever, which eventually developed after long-term PD and induced complicated pleural effusion, lung inflammation, and prolonged fever for 6 months.