2008 Volume 21 Issue 2 Pages 110-115
The annual urinalysis screening program for all school children in Japan has contributed to the early diagnosis and improvement of a therapeutic regimen for childhood chronic kidney diseases. However, there are few nationwide epidemiological surveys based on the screening program. Though idiopathic nephrotic syndrome (NS) is one of the most common kidney diseases in children, there is little nationwide epidemiological data. We explored the incidence of IgA nephropathy (IgAN) in the city of Niigata based on a screening program, and the incidence of childhood NS in Niigata prefecture through a surveillance network.
All school children in the city of Niigata who had a urinalysis screening test between 1993 and 2006 were examined. The results revealed that the screening program annually found about 0.68 cases of new onset IgAN per 10,000 school children. Children discovered in the screening program (screening group), underwent a renal biopsy at about 10.8 months after urinary abnormalities were first detected. Children who were hospitalized directly because of symptomatic onset (symptomatic onset group), underwent renal biopsy at about 5.3 months (p<0.05). By contrast with the symptomatic onset group, a significantly high number of children in the screening group archived remission of proteinuria within 2 years (p<0.05). The incidence of NS in children below age 15 in Niigata prefecture was about 4.2 per 100,000. The incidence was almost the same as the incidence about 40 years previously. However, since the number of children has decreased during this time, the cumulative number of children with NS appeared to have decreased by two thirds.
In summary, a urinalysis screening system is a useful for collecting epidemiological data and for clinical management. The expansion of a network surveillance system is essential for a nationwide epidemiological survey.
