A comparative study of IgA nephropathy between two institutions in Japan and Korea

As an approach to the geopathological evaluation of kidney disease, we conducted a comparative study on IgA nephropathy (IgANP) between Saga Medical School (SMS) in Japan and Kosin Medical College (KMC) in Korea for the period 1983-1987. The relative incidence of IgANP among primary glomerular diseases was significantly higher (P less than 0.05) at SMS (103 cases of IgANP among 250 cases of primary glomerular diseases, 41.2%) than at KMC (63 cases among 201 cases, 31.3%). Clinical and histological comparisons of the IgANP between the institutions revealed that the SMS series was generally milder than the KMC series. When the renal manifestations at the time of biopsy for all cases with primary glomerular diseases were compared, asymptomatic urinary abnormalities were more commonly found at SMS than at KMC. This suggests that certain differences in medical practice may exist between the two institutions, as follows: 1) the medical checkup system may be more efficient, 2) the accessibility to medical service may be easier, and 3) the biopsy criteria may be more liberal in Japan/SMS than in Korea/KMC. Thus, the real differences in incidence and severity of IgANP between the two institutions could be smaller than those reported here.