Etiology and pediatric chronic kidney disease progression: Taiwan Pediatric Renal Collaborative Study

Maternal risk factors in offspring with congenital anomalies of the kidney and urinary tract in Asian women

BACKGROUND

Congenital anomalies of the kidney and urinary tract (CAKUT) are the primary cause of pediatric chronic kidney disease. Maternal body mass index (BMI) before pregnancy, pregestational diabetic mellitus (DM), and gestational diabetic mellitus (GDM) are potential modifiable risk factors for CAKUT in offspring.

METHODS

In this case control study, 4619 neonates were enrolled during 2012-2020 from Kaohsiung Veterans General Hospital in Taiwan. Maternal risk factors before and during pregnancy were compared in children with and without CAKUT. The yearly incidence of CAKUT in offspring and maternal overweight were recorded.

RESULTS

In total, 73 (1.6%) cases of CAKUT in offspring were identified. Maternal overweight before pregnancy (BMI ≥ 24 kg/m2) was an independent risk factor for CAKUT in offspring. No associations of pregestational DM and GDM with CAKUT in offspring were observed. The incidence rates of CAKUT and maternal obesity have increased in the past 10 years.

CONCLUSIONS

Maternal obesity before pregnancy is associated with CAKUT in offspring and should be addressed to ensure better outcomes. A higher resolution version of the Graphical abstract is available as Supplementary information.

Differences in health-related quality of life in children with chronic kidney disease as reported by children and parent proxies

BACKGROUND

Correlation between reports of children and parent for health-related quality of life (HRQOL) is not well studied. This study aims to assess the degree of agreement between child self- and parent proxy-rated HRQOL and to identify factors associated with discordance at baseline and during follow-up in Taiwanese children with chronic kidney disease (CKD).

METHODS

This study includes pediatric patients aged 5-18 years with confirmed CKD. Participants completed the generic version of the Pediatric Quality of Life Inventory (PedsQL) at baseline and every 6 months during follow-up. Child-parent agreement on HRQOL reports was assessed using intraclass correlation coefficient (ICC). Multivariate regression models were used to determine factors associated with child-parent discordance.

RESULTS

Of the 112 child-parent dyads included in the analysis, 97 dyads with 640 patient visits were assessed in 4.5 years. Children reported higher total scores on the physical and psychosocial domains as compared to their parent proxies. ICC was low (< 0.5) for the psychosocial domain and moderate for the physical health domain at initial assessment and slightly increased for the physical health (0.62) and for school functioning (0.51) during follow-up. Development of mineral bone disorder/anemia (β, 11.75 [3.77-19.72]) and proteinuria (β, 8.48 [1.15-15.81]) in the follow-up were associated with increased discordance in school functioning, and fathers with chronic disease were associated with increased discordance in social functioning (β, 4.21 [0.68-7.74]).

CONCLUSIONS

Parent proxy consistently estimated lower PedsQL score compared to self-reports of children. Child self-rated psychosocial health domains should be evaluated whenever possible to better elucidate treatment outcome over time. A higher resolution version of the Graphical abstract is available as Supplementary information.

Novel pathogenic variants in CUBN uncouple proteinuria from renal function

BACKGROUND

Proteinuria is an unfavorable clinical condition highly associated with a risk of renal and cardiovascular disease in chronic kidney disease (CKD). However, whether all proteinuria forms are linked to renal impairment are still unclear. Cubilin is an endocytic receptor highly expressed in renal proximal tubules mediating uptake of albumin, transferrin and α1-microglobulin.

METHODS

Exome sequencing method initially identified candidate genes. With the application of exome sequencing combined with Sanger sequencing, we further focused on CUBN through bioinformatics analysis. The pathogenic effects of the potentially causative variants were verified utilizing complementary analysis of clinical data and systematic characterization of the variants' expression and function with clinical samples and in vitro experiments in HEK293T cell lines along with in vivo experiments in mice.

RESULTS

In this study, we identified four novel variants locating after the vitamin B12 (vitB12)-binding domain of Cubilin (encoded by CUBN, NM_001081.3: c.4397G > A (p.C1466Y), c.6796C > T (p.R2266X), c.6821 + 3A > G and c.5153_5154delCT (p.S1718X)) in two families. Moreover, the variants severely affected the expression and function of Cubilin in renal proximal tubules and caused albuminuria, increasing levels in urine transferrin and α1-microglobulin, but without progressive glomerular filtration barrier (GFB) impairment, vitB12 deficiencies or abnormal blood levels of HDL and albumin. Further mechanistic insights showed that the variants after the vitB12-binding domain of CUBN merely disrupted the association with Amnionless (AMN) that exhibited aberrant localization in cell cytoplasm rather than membrane.

CONCLUSIONS

Here, our findings suggested that different mutation types after the vitB12-binding domain of CUBN uncouple proteinuria from glomerular filtration barrier, that may be an unexpectedly common benign condition in humans and may not require any proteinuria-lowering treatment or renal biopsy.

Etiology, Comorbidities, and Rate of Progression of Pediatric Chronic Kidney Disease: A Cohort Study

OBJECTIVES

To evaluate the etiology of pediatric chronic kidney disease (CKD), assess comorbidities, and identify rate of progression of CKD and its risk factors.

METHODS

Children aged 2-18 y with the Kidney Disease Improving Global Outcome (KDIGO) CKD stages 2-4 were enrolled. The etiology of CKD and its comorbidities were recorded. Kaplan-Meier survival curves were used to analyze the time to progression of CKD.

RESULTS

Of the 131 patients enrolled, CKD stages 2, 3a, 3b, and 4 constituted 62 (47.3%), 17 (13%), 26 (19.8%), and 26 (19.8%), respectively. At the last follow-up [at median (IQR) 24 (12, 30) mo], the number of children in CKD stages 2, 3a, 3b, 4 and 5 were 48 (36.6%), 16 (12.2%), 23 (17.6%), 28 (21.4%), and 16 (12.2%), respectively. Etiologies of CKD included obstructive uropathy [48 (36.6%)], chronic glomerular disease [19 (14.5%)], reflux nephropathy [14 (10.7%)] and cystic renal disease [11 (8.3%)]. Comorbidities during follow-up included CKD-MBD [87 (66.4%)], metabolic acidosis [95 (72.5%)], hypertension [88 (67.1%)], growth retardation [69 (52.6%)], and anemia [63 (48.1%)]. The number of patients with metabolic acidosis, hypertension, MBD and anemia in CKD stage 2 were 27 (56%), 26 (54.2%), 24 (50%), 15 (30%), respectively. The median (IQR) rate of decline in eGFR was 3.3 (2, 4.6) mL/min/1.73 m²/y. On multivariable analysis, proteinuria [hazard ratio 3.5 (95% CI 1.4, 8.8) p = 0.01] and hyperphosphatemia [hazard ratio 2.2 (95% CI 1.1, 4.3) p = 0.03] were significant predictors for progression of CKD.

CONCLUSIONS

Even the earlier stages of CKD had significant comorbidities. The median decline in eGFR was 3.3 mL/min/1.73 m²/y. Proteinuria and hyperphosphatemia were the risk factors for progression of CKD.

Analysis of chronic kidney disease among national hospitalization data with 14 million children

BACKGROUND

The main purpose was to determine basic epidemiological data on CKD among hospitalized pediatric patients in China.

METHODS

Data from pediatric inpatients with CKD hospitalized from June 1, 2013 to May 31, 2017 were extracted from the electronic records of HQMS database, which includes over 14 million inpatients. Codes from the 10th revision of the International Classification of Diseases (ICD-10) were used to search the database.

RESULTS

A total of 524 primary diseases of CKD were included in this study. In all, there were 278 231 pediatric inpatients with CKD, which accounted for 1.95 % of the 14 250 594 pediatric inpatients registered in the HQMS database. The number of pediatric inpatients with CKD was 67 498 in 2013, 76 810 in 2014, 81 665 in 2015 and 82 649 in 2016, which accounted for 1.93 %, 1.93 %, 1.99 and 2.09 %, respectively, of the total population of pediatric inpatients. The etiology of CKD was secondary nephrosis in 37.95 % of cases, which ranked first and followed by CAKUT with a percentage of 24.61 %. Glomerular diseases and cystic kidney disease accounted for 21.18 and 5.07 %, respectively. Among all 278 231 patients, 6 581 (2.37 %) had a primary discharge diagnosis of CKD. The renal pathology findings of CKD showed that IgA accounted for 51.17 %.

CONCLUSIONS

This study provides a descriptive analysis of the hospitalized population of pediatric CKD patients. Our study provides important, fundamental data for policy making and legislation, registry implementation and the diagnosis, treatment and prevention of CKD in China.

Socio-Demographic Factors Affect the Prevalence of Hematuria and Proteinuria Among School Children in Hualien, Taiwan: A Longitudinal Localization-Based Cohort Study

Objective: Child hematuria/proteinuria is a risk factor for chronic kidney disease (CKD) in later life, and mass urinary screening could detect asymptomatic glomerulonephritis at an early stage. This study aimed to evaluate the longitudinal prevalence of hematuria/proteinuria and its association with socio-demographic factors among school children in Hualien, Taiwan. Methods: The study cohort consisted of first and fourth graders enrolled from 2008 to 2015 in Hualien. We combined the data from two consecutive health examinations to ensure the validity of the body mass index (BMI), urbanization, proteinuria, and hematuria grouping. Prevalence and health status differences between sex, age, BMI, and urbanization level were examined. Results: A total of 16,990 students within the same BMI and urbanization categories were included during the study interval. The prevalence of persistent hematuria was 1.0%. Fourth graders (odds ratio OR: 1.68, p = 0.002), girls (OR: 1.48, p = 0.014), and students from suburban/rural areas (OR: 1.99, and OR: 4.93, respectively; both p < 0.001) demonstrated higher hematuria risk. The prevalence of proteinuria was 0.2%. Fourth graders (OR: 4.44, p < 0.001) and students in suburban areas (OR: 0.27, p = 0.031) were associated with persistent proteinuria. After stratifying by age, the significant association remained. A higher risk of proteinuria was noted in underweight subjects (OR: 2.52, p = 0.023) among the fourth-grade students. Conclusion: The prevalence of hematuria/proteinuria in Hualien was higher than the average reported for Taiwan. Hematuria/proteinuria was significantly associated with sex, age, BMI, and urbanization. Our longitudinal results can provide information for future pediatric CKD prevention in Taiwan.

Blood Pressure Abnormalities Associated with Gut Microbiota-Derived Short Chain Fatty Acids in Children with Congenital Anomalies of the Kidney and Urinary Tract

Both kidney disease and hypertension can originate from early life. Congenital anomalies of the kidney and urinary tract (CAKUT) are the leading cause of chronic kidney disease (CKD) in children. Since gut microbiota and their metabolite short chain fatty acids (SCFAs) have been linked to CKD and hypertension, we examined whether gut microbial composition and SCFAs are correlated with blood pressure (BP) load and renal outcome in CKD children with CAKUT. We enrolled 78 children with CKD stage G1-G4. Up to 65% of children with CAKUT had BP abnormalities on 24 h ambulatory blood pressure monitoring (ABPM). CKD children with CAKUT had lower risk of developing BP abnormalities and CKD progression than those with non-CAKUT. Reduced plasma level of propionate was found in children with CAKUT, which was related to increased abundance of phylum Verrucomicrobia, genus Akkermansia, and species Bifidobacterium bifidum. CKD children with abnormal ABPM profile had higher plasma levels of propionate and butyrate. Our findings highlight that gut microbiota-derived SCFAs like propionate and butyrate are related to BP abnormalities in children with an early stage of CKD. Early assessments of these microbial markers may aid in developing potential targets for early life intervention for lifelong hypertension prevention in childhood CKD.

Factors associated with long-term progression of pediatric chronic kidney disease of nonglomerular etiologies

BACKGROUND/PURPOSE

The aims of this study were to determine the long-term associated factors for chronic kidney disease (CKD) progression in a pediatric group with non-glomerular (non-GN) etiologies.

METHODS

Pediatric patients with a presumptive diagnosis of CKD were enrolled to this study. Recorded information included demographic and laboratory information. We included the patients with non-GN etiologies and investigated the factors including systolic and diastolic blood pressure (BP), proteinuria, and anemia status in association with reductions in the estimated glomerular filtration rate (eGFR).

RESULTS

A total of 308 children were enrolled and the mean duration of follow-up was 4.40 ± 3.53 years. Median baseline age was 5 years old and the males represented 55% of all patients. One-unit increased baseline systolic BP z-score was associated with 1.2 ml/min per 1.73 m² (95% CI = -2 to -0.5) faster rate of eGFR decline. The presence of baseline proteinuria and anemia were also associated with 4.1 ml/min per 1.73 m² (95% CI = -5.7 to -2.5) and 2.2 ml/min per 1.73 m² (95% CI = -3.6 to -0.8) more rapid eGFR declination, respectively. Hypertension, anemia and proteinuria during the follow-up were also associated with 3.25 ml/min per 1.73 m² (95% CI = -5.32 to -1.18), 4.34 ml/min per 1.73 m² (95% CI = -7.25 to -1.43) and 4.97 ml/min per 1.73 m² (95% CI = -8.23 to -1.71) more rapid eGFR declination, respectively.

CONCLUSION

Elevated systolic BP, proteinuria, and anemia are independently associated with CKD progression in pediatric patients with non-GN etiologies.

Differential prevalence of hematuria and proteinuria with socio-demographic factors among school children in Hualien, Taiwan

BACKGROUND

Pediatric hematuria/proteinuria is a risk factor for chronic kidney disease in later life, and school urinary screening can detect asymptomatic glomerulonephritis in the early stage. This study aimed to evaluate the prevalence of hematuria/proteinuria and its association with different socio-demographic factors among school children in 2013 in Hualien, Taiwan.

METHODS

A cross-sectional study was conducted among first, fourth, and seventh graders. Health examination results and urinalysis data were analyzed. Logistic regression models were used to the simultaneously analyze the association between the prevalence of hematuria/proteinuria and socio-demographic factors.

RESULTS

A total of 9544 students were included. The overall prevalence of hematuria and proteinuria was 4.1% and 5.7%, respectively. Students who were females, of a high grade level, of aboriginal ethnicity, and living in rural areas had higher hematuria risk (all P < 0.001) than other students. Underweight students had low odds ratio (0.53) of hematuria (P < 0.001). Seventh-grade students had higher odds ratio (3.63) of proteinuria than first grade students (P < 0.001). Students with both parents of aboriginal descent had lower odds ratio (0.81) of proteinuria than those with non-aboriginal parents (P = 0.044). Only higher grade level students had significantly higher risk of combined hematuria and light proteinuria (odds ratio: 10.67) and heavy proteinuria with/without hematuria (odds ratio: 3.22) than first graders.

CONCLUSION

Increased hematuria/proteinuria prevalence was noted in our county as compared to prior studies. Hematuria/proteinuria was significantly associated with gender, grade level, body mass index, ethnicity, and residence urbanization. Our data can be used for future longitudinal dataset collection to prevent pediatric renal disorders in Taiwan.

Factors associated with diabetic nephropathy in children, adolescents, and adults with type 1 diabetes

BACKBROUD/PURPOSE

Microalbuminuria and macroalbuminuria are markers of diabetic nephropathy (DN). The purpose of this study was to unravel the risk factors for DN in the young patients with type 1 diabetes (T1D).

METHODS

341 patients (160 males) with T1D diagnosed at the age 7.6 ± 4.0 years with disease duration 11.5 ± 6.5 years were assessed. Among them, 185 were young adults (aged 18.0-36.2 years). Urinary albumin creatinine ratio (UACR) was checked on morning spot urine. Microalbuminuria and macroalbuminuria were defined as a UACR of 30-300 mg/g and >300 mg/g, respectively, in at least 2 consecutive specimens.

RESULTS

50 (14.7%) patients were classified as microalbuminuria and 13 (3.8%) as macroalbuminuria. In all patients, multivariate logistic regression revealed that the most significant risk factors were average HbA1c (%), OR (95% CI) = 1.76 (1.37-2.25), P = 0.002); and male sex, OR = (odd ratio 2.31 (1.19-4.46), P = 0.013). In adult patients, the most significant factors were average HbA1c, OR = 1.74 (1.32-2.31), P = 0.003; and systolic blood pressure, OR = 1.06 (1.01-1.11), P = 0.011. Survival analysis showed average HbA1c levels significantly influenced the development of DN.

CONCLUSION

The most important risk factors for DN were average HbA1c and age. When microalbuminuria is detected, proper treatment with ACEIs or ARBs and improving glycemic control can delay progression of DN.

Family Aggregation and Heritability of ESRD in Taiwan: A Population-Based Study

BACKGROUND

Aggregation of end-stage renal disease (ESRD) has been observed in families of European origin, as well as those of African origin. However, it is not well documented if this disease aggregates in Asian families. Furthermore, the contribution of genetic factors and shared environmental factors to family aggregation remains unclear.

STUDY DESIGN

Population-based cross-sectional cohort study.

SETTING & PARTICIPANTS

All 23,422,955 individuals registered in the Taiwan National Health Insurance Research Database in 2013. Among these, 47.45%, 57.45%, 47.29%, and 1.51% had a known parent, child, sibling, or twin, respectively. We identified 87,849 patients who had a diagnosis of ESRD.

PREDICTOR

Family history of ESRD.

OUTCOMES & MEASUREMENTS

ESRD and heritability defined as the proportion of phenotypic variance attributable to genetic factors.

RESULTS

Having an affected first-degree relative with ESRD was associated with an adjusted relative risk of 2.46 (95% CI, 2.32-2.62). Relative risks were 96.38 (95% CI, 48.3-192.34) for twins of patients with ESRD, 2.15 (95% CI, 2.02-2.29) for parents, 2.78 (95% CI, 2.53-3.05) for offspring, 4.96 (95% CI, 4.19-5.88) for siblings, and 1.66 (95% CI, 1.54-1.78) for spouses without genetic similarities. Heritability in this study was 31.1% to 11.4% for shared environmental factors and 57.5% for nonshared environmental factors.

LIMITATIONS

This was a registry database study and we did not have detailed information about clinical findings or the definite causes of ESRD.

CONCLUSIONS

This whole population-based family study in Asia confirmed, in a Taiwanese population, that a family history of ESRD is a strong risk factor for this disease. Moderate heritability was noted and environmental factors were related to disease. Family history of ESRD is an important piece of clinical information.