The Prevalence of Hematuria and Proteinuria in School Children in Seoul

BACKGROUND: Since 1998, mass urinary screening tests have been conducted in Korean school children. We analyzed the urinary screening test data gathered from the metropolitan city, Seoul, to identify the prevalence of persistent urine abnormalities. METHODS: The students were tested for hematuria and/or proteinuria using dipstick urinalysis. If the results were positive, the students were asked to visit a medical clinic to recheck urinalysis and in report their results. RESULTS: Among 1,337,210 students, who were screened with initial urinalysis, 10,871 students (proteinuria, 3,626 (0.27%); hematuria, 7,634 (0.57%); both, 389) were recommended to undergo second urinalysis in which 8,819 students (81.1%) did. Among them, 851 had persistent proteinuria and 2,618 had persistent hematuria. The results of the first urinalysis were scored based on the severity of hematuria and proteinuria from +1 to +4. Among all students 24.7% of the students who scored +1 and 40.4% who scored +3 proteinuria on the first test had persistent proteinuria, and 56.4% with both proteinuria and hematuria had persistent proteinuria on the second test. For hematuria, the more positive in the first test showed more prevalence of persistent hematuria. And 61.6% of students with both proteinuria and hematuia had persistent hematuria on the second test. CONCLUSION: The presence of both hematuria and proteinuria seemed to be a powerful predictor for persistent abnormal urine finding. And the more positive response in the first test was related to persistent abnormal finding. Therefore we should follow up closely for those students with positive findings.

Analysis of Isolated Proteinuria on School Urinary Mass Screening Test in Busan and Kyungsangnam-do Province

PURPOSE: The urinary mass screening program for the detection of urinary abnormalities in school aged population has been performed in Seoul since 1981. Nation-wide urinary mass screening program was also performed since 1998. The aim of this study was to analyze the cause and nature of isolated proteinuria detected by chance on the urinary mass screening test in Busan and Kyungsangnam-do Province. METHODS: The medical records of 44 cases of isolated proteinuria detected by chance on the urinary mass screening test in Busan and Kyungsangnam-do Province, and evaluated for urinary abnormalities at the pediatrics outpatients renal clinics of Busan Paik Hospital from April 2002 to August 2003 were reviewed prospectively. RESULTS: The cause and incidence of isolated proteinuria were as follows; transient proteinuria 4 cases(9.1%), orthostatic proteinuria 36 cases(81.8%) and persistent proteinuria 4 cases (9.1%). The total protein amount of the 24 hour urine were 121.0+/-136.4 mg in transient proteinuria, 179.1+/-130.0 mg in orthostatic proteinuria and 1532.8+/-982.5 mg in persistent proteinuria. In the orthostatic proteinuria group, the total protein amount of the 24 hour urine was in the range of 40-616 mg. Spot urine protein/creatinine ratio(PCR) were 0.10+/-0.01 in transient proteinuria, 0.61+/-0.61 in orthostatic proteinuria and 4.35+/-4.04 in persistent proteinuria. In the orthostatic proteinuria group, spot urine PCR was in the range of 0.09-2.32. Renal biopsy was performed in 4 children of the persisitent proteinuria group. They showed minimal change in 1 case, membranoproliferative glomerulonephritis in 2 cases and secondary renal amyloidosis in 1 case. CONCLUSION: The majority of isolated proteinuria which was detected by chance on school urinary mass screening were transient or orthostatic proteinuria. Even though the incidence of persistent proteinuria was much lower, it is necessary to take care of these children regularly and continuously, because persistent proteinuria itself is a useful marker of the progressive renal problems.

Analysis of Isolated Proteinuria on School Urinary Mass Screening Test in Busan and Kyungsangnam-do Province

PURPOSE: The urinary mass screening program for the detection of urinary abnormalities in school aged population has been performed in Seoul since 1981. Nation-wide urinary mass screening program was also performed since 1998. The aim of this study was to analyze the cause and nature of isolated proteinuria detected by chance on the urinary mass screening test in Busan and Kyungsangnam-do Province. METHODS: The medical records of 44 cases of isolated proteinuria detected by chance on the urinary mass screening test in Busan and Kyungsangnam-do Province, and evaluated for urinary abnormalities at the pediatrics outpatients renal clinics of Busan Paik Hospital from April 2002 to August 2003 were reviewed prospectively. RESULTS: The cause and incidence of isolated proteinuria were as follows; transient proteinuria 4 cases(9.1%), orthostatic proteinuria 36 cases(81.8%) and persistent proteinuria 4 cases (9.1%). The total protein amount of the 24 hour urine were 121.0+/-136.4 mg in transient proteinuria, 179.1+/-130.0 mg in orthostatic proteinuria and 1532.8+/-982.5 mg in persistent proteinuria. In the orthostatic proteinuria group, the total protein amount of the 24 hour urine was in the range of 40-616 mg. Spot urine protein/creatinine ratio(PCR) were 0.10+/-0.01 in transient proteinuria, 0.61+/-0.61 in orthostatic proteinuria and 4.35+/-4.04 in persistent proteinuria. In the orthostatic proteinuria group, spot urine PCR was in the range of 0.09-2.32. Renal biopsy was performed in 4 children of the persisitent proteinuria group. They showed minimal change in 1 case, membranoproliferative glomerulonephritis in 2 cases and secondary renal amyloidosis in 1 case. CONCLUSION: The majority of isolated proteinuria which was detected by chance on school urinary mass screening were transient or orthostatic proteinuria. Even though the incidence of persistent proteinuria was much lower, it is necessary to take care of these children regularly and continuously, because persistent proteinuria itself is a useful marker of the progressive renal problems.

Analysis of Isolated Proteinuria on School Urinary Mass Screening

PURPOSE: The urinary mass screening program in school aged population has been performed since 1981, but the consensus on the follow-up schedule and the management of isolated proteinuria has not been reached yet. The aim of this study was to investigate the cause of isolated proteinuria and to propose a guideline for the treatment and follow-up afterwards. Methods: The medical records of 114 cases of isolated proteinuria detected through the analysis of urinary mass screening and evaluated at the pediatric outpatient clinic of Asan Medical Center from January 1990 to July 2001 have been reviewed. RESULTS: The classification of isolated proteinuria was as follows. Transient proteinuria 32%, orthostatic proteinuria 65%, persistent proteinuria 3%. In orthostatic proteinuria group, daytime and nighttime proteinuria were 319.2+/-89.1 mg/dL and 56.5+/-6.1 mg/dL. In persistent proteinuria group, daytime and nighttime proteinuria were 1140+/-40.5 mg/dL and 289+/-8 mg/dL. After 30 month follow-up, 2 cases of persistent proteinuria were needed renal biopsy and 1 case revealed focal segmental glomerular sclerosis. In all cases, serum creatinine, albumin and complements levels were normal. In the orthostatic proteinuria group, no significant renal diseases were detected. CONCLUSION: Since most of the isolated proteinuria detected through the school urinary mass screening were orthostatic proteinuria or transient proteinuria, initially aggressive diagnostic method such as renal biopsy is not needed and regular follow-up with quantitation of proteinuria is warranted.

Analysis of Urinary Mass Screening for Second Grade of Elemantary School Children in Paju City

PURPOSE: We performed urinary mass screening(UMS) program for 2,804 children of second grade elemantary school 8 years of age in Paju city with cooperation of Paju City Health Center to determine the prevalence of asymptomatic proteinuria and hematuria, and to estimate the risk of incipient renal diseases. Also we attempted to evaluate the significance of hematuria in UMS in addidtion to proteinuria. METHODS: 2,804 children of the 2nd grade of elementary school who lived in Paju city were included to our UMS program in 2000. They were constituted with 1,428 boys and 1,376 girls. The screening program was carried out in 3 steps. The 1st screenig test was performed at schools and then students with abnormal results were examined repeatedly at Paju City Health Center and our hospital. Those students who showed proteinuria and/or hematuria in the 1st and 2nd test were referred to our hospital to undertake the 3rd close examination including physical examination, laboratory tests and radiologic tests. RESULTS: (1) The prevalence of urinary abnormality in the 1st screening test was 8.3%(233 students), comprised of 5.9% of boys, 10.8% of girls. (2) Among 2,804 children tested in the first screening, prevalences of asymptomatic proteinuria and isolated hematuria were 64(2.3%), 163(5.8%) respectively, and the prevalence of proteinuria with hematuria was 6(0.2%). (3) Among 233 students with urinary abnormalities at the 1st screening test, 102 students applied to the 2nd test. 32 children, about one third of them, were also found to have abnormal urinary findings; isolated hematuria 30, proteinuria with hematuria 2. (4) Those findings of clinical evaluation for children with isolated hematuria at the hospital showed as follows: idiopathic isolated microscopic hematuria 21, normal 6, urinary tract infection 1, idiopathic hypercalciuria 1 and simple renal cyst 1. Those 2 students with proteinuria and hematuria seemed to have chronic glomerulonephritis. CONCLUSION: (1) The clinical evaluation for children who showed positive results at the 1st screening test should be done judiciously. Because of high false positive rate, almost who showed positive results was normal, only a few of them had pathologic conditions. In this study, actual incidence of incipient renal diseases in children of 8 year old was calculated to be 0.4%. (2) The definite conclusion whether a urinary mass screening test can alter the prognosis of incipient renal diseases could not be drawn with this study. Further study must be necessary. (3) We could acknowledge the significance of hematuria in UMS, but it is necessary that one should be judicious in managing and follow-up those that show abnormal results.

Analysis of Urinary Mass Screening for Elemantary, Junior and High School Children Over a 8-year Period in Seoul

PURPOSE: The urinary mass screening program for the detection of proteinuria had been performed for a school age population in the city of Seoul since 1981. However, systematic evaluation for this program had never been done. We, therefore, designed a systematic evaluation in corporation with the Seoul School Health Center for students with proteinuria identified in the mass screening to determine the prevalence of asymptomatic proteinuria, and to estimate the risk of incipient renal diseases and incidences of some of them. And also, we attempted to reveal the significance of urinary mass screening. METHODS: In the period of 8 years betwen 1987 and 1994, annually about a half million students, who comprised 3 different age groups, 5th grade of elementary school, 2nd grade of junior school and 2nd grade of high school were chosen, corresponding to the approximate ages of 11, 14 and 17 years, respectively. These subjects accounted for 25% of total school children in Seoul. The screening program was carried out in 3 steps. The 1st test was performed at schools and the 2nd at the School Health Center. Those students who showed proteinuria in the 1st and 2nd tests were referred to the hospital. Laboratory examinations including renal biopsies were performed in those students with pathologic proteinuria to clarify the incipient renal diseases. RESULTS: 1) The prevalences of asymptomatic proteinuria were 0.2-0.36% (average 0.28%) in the 1st test. It peaked at the age of 14 years 0.36%, compared to 0.2% in the 11 age group and 0.25% in the 17 age group. 2) There was a difference of asymptomatic proteinuria by sex and age, higher prevalence in the female in the 11 age group but higher in the male in the 17 age group. 3) The distribution of proteinuria in accordance with various types classified by us at the 3rd test showed as follows: transient proteinuria (type 1) 17%, orthostatic proteinuria (type 2) 55%, constant proteinuria (type 3) 6%, proteinuria with hematuria (type 4) 20%, isolated proteinuria (type 5) 2%. Pathologic proteinuria comprised of type 3, 4 and 5, accounted for 28%, which was 1/10 of proteinuria in the 1st test. 4) The annual incidence of renal glomerular diseases among the age goup of 7-18 years was estimated to be 2.8 per 10,000. 5) Renal pathologic studies on 80 children with proteinuria and hematuria (66) or constant proteinuria (14) revealed IgA Nephropathy (38.9%) was the most frequent glomerular diease. MPGN 10.0%, MGN 7.5%, Reflux Nephropathy 7.5%, FSGS 6.2% were followed, respectively. HBV asssociated Nephropathy was 7.5%. 6) 4 of Reflux Nephropathy and 2 of FSGS were found in the 14 children with constant proteinuria in the screening test. Among these children, 5 progressed to chronic renal failure. 7) The annual incidence of IgA Nephropathy among the age group of 7-18 years was 1.1 per 10,000. 8) The morbidity of chronic renal failure was estimated to be 9.8 per 1 million of 7 to 18 years age group. CONCLUSIONS: 1) Most Students, approximately 90%, who were found to have asymptomatic proteinuria in the initial screening were normal so clinical evaluations for them should be very much cautious. Only 10% of them had pathologic proteinuria which denoted incipient renal diseases. 2) Annual incidences of incipient renal glomerular diseases, IgA Nephropathy and chronic renal failure were estimated to be 2.8 per 10,000, 1.1 per 10,000 and 9.8 per 1 million among school children in Seoul. 3) Because of the high incidence of significant glomerular changes and the high rate of progression to chronic renal failure in children with constant proteinuria, it should be regarded as serious one. 4) The definite conclusion that a urinary mass screening program can alter the prognosis of children with renal diseases identified in the mass screening can not be drawn with this study. Further study must be necessary.