A nationwide study of mass urine screening tests on Korean school children and implications for chronic kidney disease management

Demographic distribution analysis of different glomerular diseases in Southwest China from 2008 to 2022

BACKGROUND

Environmental and lifestyle factors play an etiological role in the pathogenesis of different glomerular diseases. Thus, exploring the epidemic characteristics of renal disease in different nationalities and regions is important.

MATERIALS AND METHODS

Patients who underwent renal biopsy from October 2008 to October 2022 were included. The proportion and change tendency of glomerular diseases and the differences between the sexes and different ages and races were analyzed.

RESULTS

There were 15,146 cases of glomerular diseases (98.5%), involving 7538 males (49.8%) and 7608 females (50.2%). The mean age was 37.0 years (range 0-80 years). The proportion of membranous nephropathy (MN) and diabetic nephropathy (DN) showed an increased trend. The most common primary glomerulonephritis (PGN) was IgA nephropathy (IgAN, 44.6%), followed by minimal-change disease (MCD, 24.3%) and MN (15.4%). Lupus nephritis (LN, 30%) accounted for the largest proportion of SGNs, followed by Henoch-Schonlein purpura nephritis (HSPN, 20.9%) and DN (19.8%). Compared with adults aged 18-60 years old, MCD and HSPN were more common in children and MN and DN in elderly individuals, statistically significant differences. Additionally, the sex and age distribution of PGN and SGN between the Tibetan and Han populations differed significantly, whereby LN was higher in the Han population and HSPN in the Tibetan population.

CONCLUSION

The distribution of glomerular diseases showed age, sex and race differences. This research will be beneficial for providing epidemiological evidence for clinical diagnosis, disease prevention and public health decision-making.

Review on epidemiology, disease burden, and treatment patterns of IgA nephropathy in select APAC countries

BACKGROUND

Immunoglobulin type A (IgA) nephropathy is the most common primary glomerulonephritis (GN) worldwide with higher rates in East and Pacific Asia compared to North America and Europe. Despite high reported prevalence of IgAN in these countries, the overall disease prevalence across Asia is not available. Treatment patterns of IgAN patients across Asian countries have also not been summarized. The aim of this study was to review and summarize evidence on IgA nephropathy prevalence, treatment patterns, and humanistic and economic burden in mainland China, Taiwan, South Korea, Japan, and Australia.

METHODS

A targeted literature review was conducted in PubMed and local databases in China (including Taiwan), South Korea, Japan, and Australia between January 2010-December 2021. Website literature searches were conducted using Google Scholar and Baidu.

RESULTS

Sixty-nine publications and 3 clinical guidelines were included. Incidence ranged from 0 to 10.7 per 100 000 people per year in Australia, Japan, and Taiwan, and ranged from 6.3 to 24.70% among patients who underwent renal biopsy in mainland China. Prevalence and diagnosis rates ranged from 0 to 72.1% in mainland China, South Korea, Taiwan, Japan, and Australia. Mortality rates in mainland China, South Korea, and Japan varied widely. The top 3 commonly used therapies were angiotensin-converting enzyme inhibitor/angiotensin receptor blockers (0.9-99.6%), corticosteroids (3.5-100%), and immunosuppressants (1.6-85.5%) in Japan, mainland China, and South Korea. Patient quality of life was measured by different tools, and annual hospitalization costs ranged from $1 284.73 to $2 252.12 (2015-2018) in China.

CONCLUSIONS

The prevalence of IgA nephropathy among the general population in select countries/regions is not commonly available, despite evidence from studies and clinical guidelines. In addition, it is observed across geographic regions that heterogeneity exists in prevalence rates, and large variations exist in treatment patterns. There is need to fill in these gaps to understand the contributing factors behind the differences through population-based, multi-center, and real-world studies.

IgA nephropathy in children: before and after the start of COVID-19

BACKGROUND

We describe the clinical course of children with IgA nephropathy (IgAN), diagnosed before and after the emergence of COVID-19. We hypothesized that COVID-19 vaccination and/or infection resulted in more children with IgAN to present clinically.

METHODS

We conducted a retrospective cohort study of children with IgAN diagnosed on kidney biopsy from 2014-2020 (Period 1) and 2021-2022 (Period 2). Baseline characteristics, clinical presentation, investigations and treatments were compared between patients diagnosed in Period 1 and Period 2, as well as between patients with and without chronic changes on kidney biopsy. Continuous variables were compared using the Wilcoxon rank sum test. Categorical variables were compared using χ2 or Fisher exact tests.

RESULTS

Nineteen children with IgAN were diagnosed by kidney biopsy, with 10 during Period 1 and 9 patients during Period 2 (an average of 1-2 patients/year and 4-5 patients/year in Periods 1 and 2, respectively). The most common indication for kidney biopsy is proteinuria with urine protein/creatinine ratio 1.4 (interquartile range [IQR] 1.2-9.0) vs. 0.8 (IQR 0.6-1.5) g/g (p = 0.064) at time of kidney biopsy for patients in Period 1 and 2, respectively. Clinical course was similar in both periods. No patient required acute or chronic kidney replacement therapy.

CONCLUSIONS

The rate of diagnosing children with IgAN was higher since the emergence of COVID-19, suggesting that COVID-19 may trigger an immune response responsible for IgAN, similar to other mucosal infections.

Renal pathology in adult and paediatric population of Japan: review of the Japan renal biopsy registry database from 2007 to 2017

BACKGROUND

The Japan Renal Biopsy Registry (J-RBR), a nationwide, web-based, registry system, started in 2007. This study aimed to summarise the epidemiology of biopsy-diagnosed kidney disease in Japan over 10 years.

METHODS

We analysed the J-RBR database, from 2007 to 2017. Patients' clinical data collected at the time of biopsy and histopathological diagnoses were used for epidemiological and clinicopathologic analyses.

RESULTS

The predominant renal biopsy diagnoses were immunoglobulin A nephropathy (39.2%), lupus nephritis (6.5%) and minimal change disease (6.0%) in younger adults (19-64 years), and membranous nephropathy (17.4%), antineutrophil cytoplasmic antibody-associated vasculitis or anti-glomerular basement membrane glomerulonephritis (13.0%), and immunoglobulin A nephropathy (12.5%) in older adults (≥ 65 years). The percentages of patients diagnosed with membranoproliferative glomerulonephritis and immunoglobulin A nephropathy decreased, whereas those with immunoglobulin A vasculitis and diabetic nephropathy increased over the decade. In paediatric patients (< 19 years), immunoglobulin A nephropathy (36.1%), minimal change disease (17.6%), and immunoglobulin A vasculitis (8.6%) were the predominant diagnoses. The percentage of patients diagnosed with immunoglobulin A vasculitis increased over the decade. Based on the sex distribution, minimal change disease and membranous nephropathy were predominant in men aged < 20 and > 40 years, respectively, whereas immunoglobulin A vasculitis and antineutrophil cytoplasmic antibody-associated vasculitis or anti-glomerular basement membrane glomerulonephritis were predominant in women in their 20s and 30s and aged < 50 years, respectively. Immunoglobulin A nephropathy was predominant in men at most ages and in women in their 20s to 40s.

CONCLUSIONS

This study describes the distribution and changes in kidney biopsy diagnoses over 10 years in Japan and paves the way for future research on kidney diseases in adults and children.

Clinical significance of IgM and C3 deposition in children with primary immunoglobulin A nephropathy

BACKGROUND

Mesangial IgM and C3 deposition is commonly observed in patients with primary immunoglobulin A nephropathy (IgAN), but its characteristics and prognosis have rarely been reported. The aim of this study was to investigate the relationship between combined mesangial IgM and C3 deposition and disease progression in children with IgAN.

METHODS

One hundred sixteen children diagnosed with IgAN between 2016 and 2020 were selected. Renal biopsies were scored by Oxford classification including the presence of mesangial hypercellularity, endocapillary hypercellularity, segmental glomerulosclerosis, tubular atrophy/interstitial fibrosis and crescents. The primary renal outcome was an event of either ≥ 50% reduction of eGFR from the baseline value or the onset of end-stage renal disease within the follow-up period. Cox regression analysis was performed to examine the effect of the combined mesangial IgM and C3 deposition on renal outcomes.

RESULTS

Forty-seven (40.52%) patients presented combined mesangial IgM and C3 deposition. Compared with children without combined IgM and C3 deposition, children with combined IgM and C3 deposition presented higher mesangial hypercellularity, endocapillary hypercellularity and cresentic lesions in kidney biopsies, and higher prevalence of renal dysfunction (19.15% versus 2.90%; P = 0.007). Renal outcome was also significantly worse as revealed by Kaplan-Meier curves (P = 0.0034). Multivariable Cox analysis identified tubular atrophy/interstitial fibrosis lesions [hazard ratio (HR) 14.843, 95% CI, 3.497-62.997, P < 0.001] and intensity of IgM deposition (HR 2.838, 95% CI, 1.321-6.094, P = 0.007) as independent risk factors for poor renal function.

CONCLUSIONS

Combined mesangial IgM and C3 deposition was associated with unfavorable histopathological features. Mesangial IgM deposition was an independent risk factor for poor renal outcomes in children with primary IgAN.

Clinicopathologic Manifestations of Immunoglobulin A Nephropathy in a Northern Indian Cohort: A Mute Assassin with Delayed Diagnosis

Introduction

Immunoglobulin A nephropathy (IgAN) is the most common glomerulonephritis worldwide, but there is a marked geographic difference in its prevalence and prognosis. IgAN is known to have an aggressive course in Asians. However, its exact prevalence and clinicopathologic spectrum in North India are not well documented.

Materials and Methods

The study included all patients aged above 12 years with primary IgAN on kidney biopsy from January 2007 to December 2018. Clinical and pathological parameters were noted. Two histopathologists independently reviewed all kidney biopsies, and MEST-C score was assigned as per the Oxford classification.

Results

IgAN was diagnosed in 681 (11.85%) out of 5751 native kidney biopsies. The mean age was 32 ± 12.3 years, and the male to female ratio was 2.5:1. At presentation, 69.8% had hypertension, 68% had an estimated glomerular filtration rate (eGFR) of less than 60 ml/min, 63.2% had microscopic hematuria, and 4.6% had gross hematuria. The mean proteinuria was 3.61 ± 2.26 g/day, with 46.8% showing nephrotic range proteinuria and 15.2% showing nephrotic syndrome manifestation. Histopathologically, 34.4% of patients had diffuse global glomerulosclerosis. Oxford MEST-C scoring revealed M1 in 67%, E1 in 23.9%, S1 in 46.9%, T1/T2 in 33%, and crescents in 19.6% of biopsies. The mean serum creatinine was significantly higher in cases with E1, T1/2, and C1/2 scores (P < 0.05). Hematuria and proteinuria were significantly higher (P < 0.05) with E1 and C1/2 scores. Coexisting C3 was associated with higher serum creatinine at presentation (P < 0.05).

Conclusion

IgAN patients with late presentation and advanced disease became less amenable to immunomodulation in our cohort. The implementation of point-of-care screening strategies, early diagnosis, and retarding disease progression should be prioritized in the Indian strategy.

Identification and characterization of circulating immune complexes in IgA nephropathy

The underlying pathology of immunoglobulin A (IgA) nephropathy (IgAN), the most common glomerulonephritis worldwide, is driven by the deposition of immune complexes containing galactose-deficient IgA1 [Tn(+)IgA1] in the glomerular mesangium. Here, we report that novel anti-Tn circulating immune complexes (anti-Tn CICs) contain predominantly IgM, representing large macromolecular complexes of ~1.2 megadaltons to several megadalton sizes together with Tn(+)IgA1 and some IgG. These complexes are significantly elevated in sera of patients with IgAN, which contains higher levels of complement C3, compared to healthy individuals. Anti-Tn CICs are bioactive and induce specific proliferation of human renal mesangial cells. We found that these anti-Tn CICs can be dissociated with small glycomimetic compounds, which mimic the Tn antigen of Tn(+)IgA1, releasing IgA1 from anti-Tn CICs. This glycomimetic compound can also significantly inhibit the proliferative activity of anti-Tn CICs of patients with IgAN. These findings could enhance both the diagnosis of IgAN and its treatment, as specific drug treatments are now unavailable.

Identification of High-Risk Groups in Urinalysis: Lessons from the Longitudinal Analysis of Annual Check-Ups

Background: For effective screening in urinalysis, information on high-risk groups is needed; however, there is a lack of evidence in young adults in particular. The aim of this study was to provide information on urinalysis in young adults and to identify high-risk groups of urinalyses using multi-year data obtained from annual large-scale check-ups. Method: We used annual health check-up data collected from 2011 to 2016 at Kyoto University in Japan. Eligible participants were those aged 18–39 years who underwent annual health check-ups for four consecutive years between 2011 and 2016. We conducted descriptive analyses and calculated the risk ratios (RRs) for urinary abnormalities in the fourth year of urinalysis. Results: In total, 13,640 participants (10,877 men, 79.7%) met the eligibility criteria. The mean prevalence rates of proteinuria, haematuria and glucosuria were 1.61% (men: 1.63%; women: 1.53%), 1.48% (men: 0.53%; women: 5.22%) and 0.46% (men: 0.52%; women: 0.25%), respectively. Participants with urinary abnormalities at least once in the initial 3 years had a higher risk of urinary abnormalities in the fourth year than participants with no abnormal findings in the initial 3 years; the risk ratios (RRs) of proteinuria, haematuria and glucosuria were 3.5 (95% confidence interval (CI) = 3.2–3.7), 12.2 (95% CI = 11.7–12.7) and 42.6 (95% CI = 37.7–48.1), respectively. The RRs of all urinary abnormalities in the fourth year increased as the frequency of urinary abnormalities over the preceding 3 years increased. In haematuria, differences of the RR were observed between men and women. Conclusion: We clarified the prevalence of urinary abnormalities in young adults and high-risk groups of urinary abnormalities. Our findings support the need for multi-year annual urinalysis.

Glomerular Hematuria and the Utility of Urine Microscopy: A Review

Evaluation of hematuria and microscopic examination of urine sediment are commonly used tools by nephrologists in their assessment of glomerular diseases. Certain morphological aspects of urine red blood cells (RBCs) seen by microscopy may help in identifying the source of hematuria as glomerular or not. Recognized signs of glomerular injury are RBC casts or dysmorphic RBCs, in particular acanthocytes (ring-shaped RBCs with protruding blebs). Despite being a highly operator-dependent test, urine sediment examination revealing these signs of glomerular hematuria has demonstrated specificities and positive predictive values ranging between 90%-100% for diagnosing glomerular disease, although sensitivity can be quite variable. Hematuria is a commonly used tool for diagnosing patients with proliferative glomerulonephritis such as IgA nephropathy, antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, and lupus nephritis, sometimes even as a surrogate for kidney involvement. Studies examining the role for hematuria in monitoring and predicting adverse outcomes in these diseases have shown inconsistent results, possibly due to inconsistent definitions that often fail to consider specific markers of glomerular hematuria such as dysmorphic RBCs, acanthocytes, or RBC casts. A consensus definition of what constitutes glomerular hematuria would help standardize use in future studies and likely improve the diagnostic and prognostic value of hematuria as a marker of glomerulonephritis.

Trends of primary glomerular disease in Turkey: TSN-GOLD registry report

BACKGROUND

Although several renal biopsy registry reports have been published worldwide, there are no data on primary glomerular disease trends in Turkey.

METHODS

Three thousand eight-hundred fifty-eight native kidney biopsy records were assessed in the Turkish Society of Nephrology Primary Glomerulopathy Working Group (TSN-GOLD) Registry. Secondary disease and transplant biopsies were not recorded in the registry. These records were divided into four periods, before 2009, 2009 to 2013, 2013-2017, and 2017-current.

RESULTS

A total of 3858 patients (43.6% female, 6.8% elderly) were examined. Nephrotic syndrome was the most common biopsy indication in all periods (58.6%, 53%, 44.1%, 51.6%, respectively). In the whole cohort, IgA nephropathy (IgAN) (25.7%) was the most common PGN with male predominance (62.7%), and IgAN frequency steadily increased through the periods (× 2 = 198, p < 0.001). MGN was the most common nephropathy in the elderly (> 65 years), and there was no trend in this age group. An increasing trend was seen in the frequency of overweight patients (× 2 = 37, p < 0.0001). Although the biopsy rate performed with interventional radiology gradually increased, the mean glomeruli count in the samples did not change over the periods.

CONCLUSIONS

In Turkey, IgAN is the most common primary glomerulonephritis, and the frequency of this is increasing.

Urine Screening and 9 Years' Medical Record System Follow-Up Among School Students in Wenzhou, China

School urinary screening programming can be useful for the early detection of renal and urinary disorders. However, urine screening is not included in the school health check-up in our region. Therefore, from February 2012 to March 2021, 12,497 school students were screened for urinalysis, and a long-term follow-up took place via an electronic medical record system. Among these screened students, 719 (5.75%) positive individuals received a repeat urinalysis 2 weeks later. During the 9-year medical record system follow-up period, 5 children had renal biopsies and 2 children had a diagnosis of IgA nephropathy (IgAN), while the remaining 3 children were diagnosed with thin basement membrane disease (TBM), primary nephrotic syndrome (PNS), and were suspected of C3 glomerulopathy, respectively. By this, calling for the school urine screening program as a physical examination item for primary and secondary school-aged students will contribute to enabling early detection of urine abnormalities and allow for early treatment.

Management of the congenital solitary kidney: consensus recommendations of the Italian Society of Pediatric Nephrology

In recent years, several studies have been published on the prognosis of children with congenital solitary kidney (CSK), with controversial results, and a worldwide consensus on management and follow-up is lacking. In this consensus statement, the Italian Society of Pediatric Nephrology summarizes the current knowledge on CSK and presents recommendations for its management, including diagnostic approach, nutritional and lifestyle habits, and follow-up. We recommend that any antenatal suspicion/diagnosis of CSK be confirmed by neonatal ultrasound (US), avoiding the routine use of further imaging if no other anomalies of kidney/urinary tract are detected. A CSK without additional abnormalities is expected to undergo compensatory enlargement, which should be assessed by US. We recommend that urinalysis, but not blood tests or genetic analysis, be routinely performed at diagnosis in infants and children showing compensatory enlargement of the CSK. Extrarenal malformations should be searched for, particularly genital tract malformations in females. An excessive protein and salt intake should be avoided, while sport participation should not be restricted. We recommend a lifelong follow-up, which should be tailored on risk stratification, as follows: low risk: CSK with compensatory enlargement, medium risk: CSK without compensatory enlargement and/or additional CAKUT, and high risk: decreased GFR and/or proteinuria, and/or hypertension. We recommend that in children at low-risk periodic US, urinalysis and BP measurement be performed; in those at medium risk, we recommend that serum creatinine also be measured; in high-risk children, the schedule has to be tailored according to kidney function and clinical data.

IgA Nephropathy: A Chinese Perspective

Background

IgA nephropathy (IgAN) is the most common primary glomerular disease worldwide and remains a leading cause of chronic kidney disease and end-stage renal disease. The disease prevalence, clinical and pathological phenotypes, the underlying pathogenic molecular mechanisms, and the response to treatments are highly heterogeneous in different ethnic populations, which raise the concern that IgAN may differ across different parts of the world.

Summary

From a Chinese perspective, we stated the disease burden of IgAN, summarized genome-wide association studies and research into pathological molecules, and compared them with findings based on other populations. The emerging biomarkers, indigenous clinical trials, and major challenges for Chinese researchers and nephrologists in studying IgAN are also discussed.

Key Messages

In this review, we described a higher risk of major susceptible loci in mucosal immunity, IgA production, and complement activation pathways in Chinese patients with IgAN. With our understanding of the pathogenesis of IgAN, novel biomarkers are emerging. Although there are challenges for conducting high-quality clinical trials in China, it is still feasible to conduct innovative and well-designed studies of IgAN. In the future, international collaborations on research infrastructure would be helpful to advance clinical and basic research in China.

Streptococcus mutans induces IgA nephropathy-like glomerulonephritis in rats with severe dental caries

The mechanisms underlying immunoglobulin A nephropathy (IgAN), the most common chronic form of primary glomerulonephritis, remain poorly understood. Streptococcus mutans, a Gram-positive facultatively anaerobic oral bacterium, is a common cause of dental caries. In previous studies, S. mutans isolates that express Cnm protein on their cell surface were frequently detected in IgAN patients. In the present study, inoculation of Cnm-positive S. mutans in the oral cavities of 2-week-old specific-pathogen free Sprague-Dawley rats fed a high-sucrose diet for 32 weeks produced severe dental caries in all rats. Immunohistochemical analyses of the kidneys using IgA- and complement C3-specific antibodies revealed positive staining in the mesangial region. Scanning electron microscopy revealed a wide distribution of electron dense deposits in the mesangial region and periodic acid-Schiff staining demonstrated prominent proliferation of mesangial cells and mesangial matrix. These results suggest that IgAN-like glomerulonephritis was induced in rats with severe dental caries by Cnm-positive S. mutans.

Risk Factors Associated With Abnormal Urinalysis in Children

Background: Targeted urinalysis has been suggested to improve screening efficiency in adults. However, there is no well-defined target population in children yet, with limited information on the risk factors for urinalysis abnormalities. Methods: Children from infants to 17 years old were randomly selected. Dipstick urinalysis was initially performed. Among those who were abnormal, a repeat dipstick or dipstick with microscopic urinalysis was performed for confirmation. Results: In total, 70,822 children were included, with 37,866 boys and 32,956 girls. Prevalence of abnormal urinalysis was 4.3%. Age was significantly associated with abnormal urinalysis, with the highest prevalence among 12-14-year-olds. Girls were 2.0 times more likely to exhibit abnormalities. Compared with children whose guardians had a college degree or higher, those whose guardians had a high school degree or lower had a higher likelihood of abnormalities. Geographic location was also associated with abnormal results. Conclusion: Girls, children aged 12-14 years old, and children whose guardians had a low educational level and children in certain geographic locations were significantly associated with abnormal urinalysis. Identification of children at high risk would contribute to targeted urinalysis screening.

Updating the International IgA Nephropathy Prediction Tool for use in children

Although IgA nephropathy (IgAN) is a common cause of glomerulonephritis in children, the absence of a method to predict disease progression limits personalized risk-based treatment decisions. The adult International IgAN Prediction Tool comprises two validated Cox survival models that predict a 50% decline in estimated glomerular filtration rate (eGFR) or end stage kidney disease (ESKD) using clinical risk factors and Oxford MEST histology scores. Here, we updated the Prediction Tool for use in children using a multiethnic international cohort of 1,060 children with IgAN followed into adulthood. The updated pediatric Prediction Tool had better model fit than the original adult tool with lower Akaike Information Criterion, higher R²_D and similar C-statistics. However, calibration showed very poor agreement between predicted and observed risks likely due to the observed disease trajectory in children. Therefore, the Tool was updated using a secondary outcome of a 30% reduction in eGFR or ESKD, resulting in better R²_D (30.3%/22.2%) and similar C-statistics (0.74/0.68) compared to the adult tool but with good calibration. The trajectory of eGFR over time in children differed from adults being highly non-linear with an increase until 18 years old followed by a linear decline similar to that of adults. A higher predicted risk was associated with a smaller increase in eGFR followed by a more rapid decline, suggesting that children at risk of a 30% decrease in eGFR will eventually experience a larger 50% decrease in eGFR when followed into adulthood. As such, these two outcomes are analogous between pediatric and adult Prediction Tools. Thus, our pediatric Prediction Tool can accurately predict the risk of a 30% decline in eGFR or ESKD in children with IgAN.

Remission of Proteinuria May Protect against Progression to Chronic Kidney Disease in Pediatric-Onset IgA Nephropathy

Immunoglobulin A nephropathy (IgAN) is one of the most common primary glomerulopathies diagnosed in children and adolescents. This study aimed to evaluate the clinical features in and outcomes of pediatric IgAN over the last 30 years. Patients who were diagnosed before age of 18 at 20 centers in Korea were evaluated retrospectively. Of the 1154 patients (768 males, 386 females) with a median follow-up of 5 years, 5.6% (n = 65) progressed to stage 3–5 chronic kidney disease (CKD). The 10- and 20-year CKD-free survival rates were 91.2% and 75.6%, respectively. Outcomes did not differ when comparing those in Korea who were diagnosed prior to versus after the year 2000. On multivariate analysis, combined asymptomatic hematuria and proteinuria as presenting symptoms and decreased renal function at the time of biopsy were associated with progression to CKD, while remission of proteinuria was negatively associated with this outcome. Patients who presented with gross hematuria or nephrotic syndrome tended toward positive outcomes, especially if they ultimately achieved remission. While remission of proteinuria might imply that the disease is inherently less aggressive, it also can be achieved by management. Therefore, more aggressive management might be required for pediatric-onset IgAN.

IgA nephropathy in children and in adults: two separate entities or the same disease?

IgA nephropathy (IgAN) is observed in subjects of any age, however perspective and management of this disease are different between adult and pediatrician Nephrologists. Most children with IgAN present with gross hematuria rapidly vanishing or persistent mild microscopic hematuria, which rarely progresses to end stage renal disease (ESRD) over the pediatric observation. The perspective of IgAN in adults is of a slowly progressive glomerular disease with 30-40% probabilities to reach ESRD. However, mild cases of IgAN in children might be missed with manifestation of irreversible damage only decades after the true onset, as 50% of subjects with IgAN enter renal replacement treatment before the age of 50 years. In both adults and children the assessment of risk profile is crucial to avoid overtreatment in benign cases or institute a prompt and valid therapy in potentially progressive cases. In case of common risk factors, new therapeutic opportunities tested in adults might be applied to children with the expectation of similar results. If IgAN is the same disease in spite of different clinical profiles in children and adults, an early intervention may be the correct way to prevent progression decades later. On the contrary, if we are dealing with different clinical entities, the treatment in pediatric and in adult settings must be kept apart. This review addresses to report similarities and differences of IgAN across the life periods in order to reason on the application of newly offered treatments over the entire spectrum of this disease or in focused age indications.

Uptake of further investigations following universal urinary screening among elementary and junior high school students in Shiga Prefecture, Japan: A retrospective cohort study

AIM

This study aimed to investigate the current progression status from screening phase to further investigation phase in the Japanese school urine mass screening (SUS) project.

METHODS

This retrospective cohort study on the SUS project across the Shiga Prefecture during 2012 to 2017 analysed data from school life instruction sheets, which are principal documents in the SUS project, regarding urinalysis, attendance at follow-up and diagnoses.

RESULTS

Between the years 2012 to 2017, a median of 107 out of 83 749 elementary school students (aged 6-11 years) and 215 out of 42 870 junior high students (aged 12-14 years) had urine abnormalities identified for the first time in the SUS project. Among those with urine abnormalities, a mean of 4.2% of elementary school and 1.8% of junior high school students, respectively, were diagnosed with suspected glomerulonephritis for the first time. Overall, 5.9% (95% confidence interval [CI] 4.1, 7.7) and 23.6% (95% CI 21.3, 25.9) of proteinuria-positive elementary and junior high school students, respectively, did not undergo further investigations. The probability of a student undergoing further investigations was not affected by the local availability of medical care benefits.

CONCLUSION

In the current SUS project, screening frequently does not lead to further investigation, especially among junior high school students. To maintain the integrity of the SUS project and to prevent the progression of renal disease in young students, efforts including elucidation of barriers to further investigations should be made to reduce the proportions of students not undergoing further investigations for abnormal urinalysis findings.

Steroid therapy in children with IgA nephropathy

IgA nephropathy (IgAN) is one the most common primary glomerulonephritis in children and adolescents worldwide, with 20% of children developing end-stage kidney disease (ESKD) within 20 years of diagnosis. There is a need for treatment guidelines, especially for steroids in children with primary IgAN, since the STOP-IgA trial casts doubts on the use of steroids in adults with intermediate risk. Pediatricians are prone to prescribe steroids in addition to renin-angiotensin system blockade (RASB) when proteinuria is > 0.5 g/l, eGFR deteriorates < 70 ml/min/1.73 m², or when a biopsy sample shows glomerular inflammation. Lack of randomized controlled trials (RCTs) in children with IgAN has led to an absence of consensus on the use of immunosuppressive agents in the treatment of progressive IgAN. This literature review evaluates the available evidence on steroid treatment in children with IgAN.

Identification of children with chronic kidney disease through school urinary screening using urinary protein/creatinine ratio measurement: an observational study

Background

School urinary screening has been performed in Japan.

Methods

Ikeda City and Toyono Town introduced, in 2012 and 2013, urinary protein/creatinine (Cr) ratio measurement into the urine-screening protocols designed for students aged between 4 and 15 years. For each student whose urinary protein/Cr ratio was ≥ 0.15 g/gCr (positive case), an appointment was made with a specialist at Ikeda City Hospital. The results of these screening urinalyses conducted through 2018 are summarized.

Results

14,606 junior high and elementary school students aged between 6 and 15 years were included. On average, they underwent 4.16 screening tests. 77 positive cases were detected, and seven students were diagnosed with high-risk chronic kidney disease (CKD). Of these, four underwent renal biopsy, and two, one, and one were diagnosed with IgA nephropathy, MPGN, and FSGS, respectively. In three students, detection of CKD would have been difficult without urinary screening. Incident rates of high-risk CKD and IgA nephropathy are estimated as 11.5 and 3.3 cases/100,000 students/year. 78.0% of positive cases without high-risk CKD showed no urinary abnormality after one year. 2301 kindergarten students aged between 4 and 6 years received an average of 1.74 screening urinalyses; none was positive or high-risk CKD. The estimated cost of detecting one high-risk CKD student whose detection would have been difficult without this screening was 3,156,711 Japanese yen.

Conclusion

School urinary screening using the urinary protein/Cr ratio can efficiently refer to a specialist. It detects a few children with high-risk CKD early with spending high cost.

Electronic supplementary material

The online version of this article (10.1007/s10157-020-01852-5) contains supplementary material, which is available to authorized users.

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.

[An epidemiological investigation of chronic kidney disease in children with hearing disorder in Hunan province, China]

OBJECTIVE

To investigate the prevalence of chronic kidney disease (CKD) among the children with hearing disorder in Hunan province, China.

METHODS

In this cross-sectional study, the multi-stage cluster sampling method was used to select 1 500 children as subjects. Questionnaire surveys, physical examinations, and laboratory examinations were performed on the spot.

RESULTS

Among the 1 500 children, 1 459 with complete data were included in analysis. Among the 1 459 children, 43 had CKD, with a prevalence rate of 2.95%. The <7 years group had a significantly higher prevalence rate than the 7-14 years group [5.8% (35/604) vs 0.9% (8/855); P<0.05]. Among the 43 children with CKD, 31 (72%) had proteinuria, 27 (63%) had hematuria, and 11 (26%) had a decreased glomerular filtration rate. Among the 43 children with CKD, stage 1, 2, 3a, 3b, 4, and 5 CKD accounted for 30% (13 cases), 44% (19 cases), 12% (5 cases), 7% (3 cases), 7% (3 cases), and 0% (0 case) respectively. The prevalence rate of CKD increased with the severity of hearing disorder (P<0.01).

CONCLUSIONS

The prevalence rate of CKD is higher among the children with hearing disorder in Hunan province. Most children have early-stage CKD. CKD is commonly seen in preschool children. Severity of hearing disorder is associated with the prevalence of CKD.

Epidemiology of IgA Nephropathy: A Global Perspective

IgA nephropathy (IgAN), or Berger's disease, is the most common primary glomerular disease worldwide, but varies largely in its geographic distribution. A systematic review of 1,619 publications from the five continental regions of the world was performed to assess the prevalence of IgAN in different worldwide regions and analyze factors responsible for geographic differences. All observational studies that described the prevalence and incidence data on glomerulonephritis were considered. IgAN is more frequent in Asian populations (45 cases per million population/y in Japan) than in Caucasians (31 cases per million population/y in France). These differences are owing to some relevant aspects: (1) systematic mass screening of urine in populations, as occurring in some Asian countries (Hong Kong, Japan, Korea, and Singapore), is not common in Western countries; (2) general practitioners and health care professionals in Western countries underestimate persistent microscopic hematuria and/or mild proteinuria in apparently healthy individuals causing late referral to a nephrologist; and (3) nephrologists adopt different indications for kidney biopsy in individuals with persistent urinary abnormalities. In addition, differences also are owing to the source of data, because the frequency of IgAN observed in a nephrology center with a high incidence of kidney biopsies is higher than in a regional renal biopsy registry that receives data from many centers. In conclusion, greater efforts should be made to diagnose IgAN earlier in individuals who manifest persistent microhematuria and/or mild proteinuria and to introduce less stringent indications for kidney biopsies. This preventive approach, followed by early therapy, may reduce the global burden of end-stage kidney disease caused by IgAN.

Pediatric IgA Nephropathy in Europe

Background

In Europe IgA nephropathy (IgAN) is detected in 20% of children with glomerular diseases diagnosed by renal biopsy. The outcome during childhood is generally good, but progression in the long-term follow-up may occur in about 20% of children after 20 years.

Summary

In Europe, urine screening programs are not active, and there is variability in the policy to perform renal biopsies in oligo-symptomatic children. Hence, a suitable observational approach to pediatric IgAN is offered by the VALIGA study which included 174 children aged < 18 years from 13 European countries followed over a median of 4.4 (2.5-7.5) years. Renal pathology lesions were centrally scored according to the Oxford Classification of IgAN (mesangial hypercellularity, M; endocapillary hypercellularity, E; segmental glomerulosclerosis, S; tubular atrophy/interstitial fibrosis, T; crescents, C [MEST-C]). Children had renal biopsy mostly with normal estimated glomerular filtration rate (eGFR) and moderate proteinuria of a median of 0.84 g/day/1.73 m² (< 0.30 g/day/1.73 m² in 30% of the cases). Children showed M1 in 21.8%, E1 in 13.8%, S1 in 42.5%, T1-2 in 6.3%, and C1 in 14.9%. The survival at the combined endpoint of 50% eGFR decrease or end-stage renal disease at 15 years was 94%. The slow progression rate and the limited number of cases progressing to the combined endpoint (6.4%) did not allow the detection of a predictive value of the MEST-C score. Moreover, the predictive value of clinical and pathological features was likely blunted by the use of corticosteroid/immunosuppressive treatment (CS/IS) in 50% of the cases. The survival tree analysis also proved that children < 16 years old with IgAN without mesangial hypercellularity (M0) and well preserved eGFR (> 90 mL/min/1.73 m²) had a high probability of proteinuria remission during follow-up. Moreover, in this subgroup of children, the benefits of CS/IS therapy reached statistical significance. In Europe, the use of CS/IS treatment in IgAN is still a debated issue, but most children tend to be treated more commonly than adults with CS/IS. A recent uncontrolled study reports a favorable outcome in European children with IgAN and very active acute forms of IgAN with improvement in eGFR and reduction in proteinuria.

Key Messages

In Europe, children with IgAN have a favorable prognosis in the short term, and this may be due also to the frequently adopted CS/IS therapy, particularly with acute and active pathological features. The risk of progression over decades of follow-up remains an unsolved problem which needs to be addressed by controlling subtle chronic pathogenetic factors which work in children as well as in adult cases of IgAN.

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.

The Spectrum of Biopsy-Proven Glomerular Diseases among Children in China: A National, Cross-Sectional Survey

BACKGROUND AND OBJECTIVES

High-quality epidemiologic data on the spectrum of biopsy-proven glomerular diseases among children are limited. This study aimed to determine the profile of and temporal change in biopsy-proven pediatric glomerular diseases in China.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We previously conducted a nationwide kidney biopsy survey including 71,151 patients over an 11-year period from January 2004 to December 2014. A total of 7962 children younger than 18 years old from 115 hospitals across China with biopsy-proven glomerular diseases were included in this study. The demographic and clinical variables were extracted from referral records and pathology reports. The composition of pediatric glomerular diseases and clinicopathologic correlations in different sexes, age groups, and regions were assessed. The changing patterns of common glomerulopathies over the study period were examined.

RESULTS

Nephrotic syndrome (50%) was the most frequent indication for kidney biopsy in children. Minimal change disease was the most common primary glomerular disease (29%) followed by IgA nephropathy (17%). Henoch-Schonlein purpura nephritis (13%) and lupus nephritis (9%) were the most common secondary glomerular diseases. The proportion of minimal change disease was significant higher in boys (38%) than in girls (13%), whereas lupus nephritis was more prevalent in girls (20%) than in boys (3%). Purpura nephritis (23%) was the major pathologic pattern in younger children (0-12 years old), whereas minimal change disease (33%) was the most common glomerulopathy in adolescents (13-18 years old). The clinicopathologic correlations were slightly different between sexes and age groups. We observed increases in the proportions of minimal change disease, purpura nephritis, and membranous nephropathy over the study period that were contemporaneous with a fall in the proportion of FSGS.

CONCLUSIONS

The spectrum of glomerular diseases among children varied across sexes, age groups, and regions and changed substantially from 2004 to 2014 in China.

Urinary Glucose Screening for Early Detection of Asymptomatic Type 2 Diabetes in Jeonbuk Province Korean Schoolchildren

This study aimed to investigate the prevalence of glucosuria and the characteristics of diabetes in schoolchildren as detected by a school urine glucose screening program implemented from 2010 to 2013 in the Jeonbuk province area of Korea. A total of 110 children without known diabetes were analyzed. They were checked with an oral glucose tolerance test (OGTT) with other laboratory tests and their clinical data were collected. A total of 707,238 schoolchildren from a school population of 1,064,999 were screened for glucosuria. In total, over a 4-year period, 545 schoolchildren (0.077%) were positive for glucosuria on the second urine test. The prevalence of glucosuria was more common among middle and high schoolchildren than among elementary schoolchildren. Among 110 students who completed the OGTT to confirm diabetes, 40 were diagnosed with diabetes mellitus (DM); 39 children, type 2 diabetes mellitus (T2DM) and 1 child, slowly progressive insulin dependent diabetes mellitus (SPIDDM). The mean annual incidence of diabetes was 5.6 per 100,000 schoolchildren and adolescents. The subjects with diabetes diagnosed through the urine screening test showed minimal or no symptoms of diabetes. The students with diabetes were more likely to be woman and obese, and they have a higher body mass index, higher cholesterol, triglyceride, insulin, C-peptide, and fasting glucosuria values than the students with normal glucose tolerance. We identified 40 new cases of diabetes in the Korean schoolchildren with asymptomatic glucosuria on urine glucose screening. This finding shows that school urine glucose screening is a feasible and simple method for early detection of asymptomatic T2DM.

Clinical and histopathological features of asymptomaticpersistent microscopic hematuria in children

BACKGROUND/AIM

We analyzed the clinical and pathological features and prognosis of 106 children with persistent asymptomatic microscopic hematuria (PAMH) with or without mild proteinuria.

MATERIALS AND METHODS

This was a retrospective study of 106 children who were referred to our clinics from 2000 to 2013 for evaluation of PAMH.

RESULTS

Among the 106 patients, 69 (65%) were female and 37 (35%) were male. The patients were divided into two groups: 101 patients with isolated microscopic hematuria (IMH) and 5 patients with asymptomatic microscopic hematuria and mild proteinuria (AMHP). Renal biopsy was performed in all 5 children with AHMP: 2 patients had hereditary nephropathy and 2 patients had focal segmental glomerulosclerosis (FSGS). One biopsy specimen revealed nonspecific findings. Renal biopsy was performed in 9 children with IMH: 4 patients had hereditary nephropathy and 5 patients had nonspecific findings. None of the patients received any specific treatment prior to renal biopsy. During the follow-up period, none of the patients developed impaired renal function. Among all the children, only one patient with AMHP developed hypertension and 2 patients with IMH developed proteinuria.

CONCLUSION

Long-term follow-up must be done carefully for isolated microscopic hematuria and renal biopsy should be performed in selected cases.

A Cross-Sectional Study on the Use of Urinalysis for Screening Early-Stage Renal Insufficiency

BACKGROUND/AIMS

Proteinuria and hematuria detected by routine urinalysis can indicate impaired renal function. This study evaluated the effect of routine urinalysis in screening out patients with estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2 at an early stage and investigated its associated factors.

METHODS

Healthy adults who underwent physical examination between September 2008 and September 2013 were enrolled in the study (n = 43,516). Urine was analyzed for protein, and red and white blood cells. Ten milliliter blood samples were collected for serum creatinine, urea, albumin and other parameters for the estimation of eGFR and renal function.

RESULTS

Abnormal routine urinalysis was found in 7.1% and eGFR <60 ml/min/1.73 m2 was found in 0.9% of subjects. Age and gender were similar in the overall and abnormal urinalysis populations (43 vs. 43 years and 36.7 vs. 38.2% females, respectively), but the eGFR <60 ml/min/1.73 m2 group were older (64 years, p < 0.001) with increased females (46.4%, p = 0.002). Sensitivity for predicting eGFR <60 ml/min/1.73 m2 was 0.110 and specificity was 0.928. Univariate and multivariate analyses in 6,318 subjects with more detailed clinical data suggested significant associations of sex (OR 0.058, 95% CI 0.030-0.113), age (OR 1.045, 95% CI 1.027-1.064), and high density lipoprotein (HDL) (OR 0.158, 95% CI 0.043-0.587) with eGFR <60 ml/min/1.73 m2.

CONCLUSION

Routine urinalysis showed a poor performance in the screening for early-stage renal insufficiency. In future, other screening methods should be considered. Age, gender and HDL were associated with eGFR <60 ml/min/1.73 m2.

IgA nephropathy

Globally, IgA nephropathy (IgAN) is the most common primary glomerulonephritis that can progress to renal failure. The exact pathogenesis of IgAN is not well defined, but current biochemical and genetic data implicate overproduction of aberrantly glycosylated IgA1. These aberrant immunoglobulins are characterized by galactose deficiency of some hinge-region O-linked glycans. However, aberrant glycosylation alone is insufficient to induce renal injury: the participation of glycan-specific IgA and IgG autoantibodies that recognize the undergalactosylated IgA1 molecule is required. Glomerular deposits of immune complexes containing undergalactosylated IgA1 activate mesangial cells, leading to the local overproduction of cytokines, chemokines and complement. Emerging data indicate that mesangial-derived mediators that are released following mesangial deposition of IgA1 lead to podocyte and tubulointerstitial injury via humoral crosstalk. Patients can present with a range of signs and symptoms, from asymptomatic microscopic haematuria to macroscopic haematuria. The clinical progression varies, with 30-40% of patients reaching end-stage renal disease 20-30 years after the first clinical presentation. Currently, no IgAN-specific therapies are available and patients are managed with the aim of controlling blood pressure and maintaining renal function. However, new therapeutic approaches are being developed, building upon our ever-improving understanding of disease pathogenesis.

Clinicopathological analysis of 155 patients with persistent isolated hematuria

OBJECTIVES

To reveal etiologies of persistent isolated hematuria (PIH) through ultrastructural pathological examination, to disclose clinicopathological correlation in cases with PIH, and to summarize appropriate management of patients with PIH.

METHODS

we retrospectively studied 155 PIH patients receiving renal biopsy between January, 2003 and December, 2008 in Peking Union Medical College Hospital. All the clinical data and follow-up result were analyzed.

RESULTS

All subjects included 38 children and 117 adults, with mean age of 11.38±3.25 years for children and 35.17±8.44 years for adults. Thin basement membrane nephropathy (TBMN) was the most common pathology (55.3% of children and 49.6% of adults), followed by IgA nephropathy (18.4% of children and 32.5% of adults, mainly grade 2-3) and mesangial proliferative glomerulonephritis (MsPGN) without IgA deposition (13.2% of children and 12.8% of adults). Besides, Alport syndrome (2.6% of children) and membrane nephropathy (2.6% of children and 0.9% of adults) were demonstrated as other causes of PIH. Elevated mean arteral pressure or protein excretion rate, as well as episodic macrohematuria, indicated higher risk for MsPGN rather than TBMN. On the other hand, severity of microhematuria was irrelevant to pathological types of PIH. Totally, 86 patients were followed up and 37 cases therein stayed on track for long term (mean duration 41.11?28.92 months, range 8-113 months). Most cases had benign clinical course except 3 cases with TBMN, 5 cases with IgA nephropathy, 1 case with MsPGN (without IgA deposition), and 1 case with Alport syndrome, who developed hypertension or proteinuria. All of them were administered timely intervention.

CONCLUSIONS

Close follow-up should be required as the primary management for PIH. Equally important is careful monitoring for early identification of undesirable predictors; while renal biopsy and other timely intervention are warranted if there is hypertension, significant proteinuria or renal impairment.

Restructuring the Ikeda City school urinary screening system: report of a screening survey

BACKGROUND

Annual urinary screening is conducted at municipal kindergartens, elementary schools, and junior high schools in Ikeda City, Osaka, Japan (Ikeda City School System), and the results are reviewed by a general physician, but standards for when to recommend specialist referral have not been clear.

METHODS

In all children attending the Ikeda City School System in 2012, dipstick urinalysis of a first-morning urine specimen was recommended once or twice, and if a second urinalysis showed proteinuria (≥1+), the urinary protein/creatinine ratio was measured. If this showed ≥0.2 g/g of creatinine (g/gCr), it was recommended that the child be evaluated by a specialist at Ikeda City Hospital.

RESULTS

Urinary screening was performed in about 20% (388) of kindergarten, about 90% (5363) of elementary school, and about 86% (2523) of junior high school children living in Ikeda City. Urine samples were obtained from 387, 5349, and 2476 children, respectively. The urinary protein/creatinine ratio was ≥0.2 g/gCr in 13 children, including 1 elementary and 12 junior high children. In these 13 children, chronic nephritic syndrome (CNS) was suspected in 6 junior high school children, and of these, this was a new finding in 5, and renal biopsy was indicated in 3. In Ikeda City, the prevalence of CNS in elementary school children was <0.03%, the prevalence of CNS in junior high school children was 0.29%, and a renal biopsy was indicated in 0.14%. By eliminating the costs associated with assessment of the results by the Ikeda Medical Association, and by directly contracting with the testing company, the expenses paid by Ikeda City for the system itself decreased from 2,508,619 yen to 966,157 yen.

CONCLUSIONS

Incorporating the urinary protein/creatinine ratio into the school urinary screening system in the Ikeda City School System and clarifying standards for specialist referral has enabled restructuring of the system so that is efficient and its effectiveness can be assessed.