Proposal for mapping renal failure in Japan and its application for strategy to arrest endstage renal disease

Need for education on the differential diagnosis between chronic glomerulonephritis and nephrosclerosis, and treatment of both conditions to reduce the number of patients requiring hemodialysis in Wakayama

OBJECTIVE

We investigated the present state of, and trends in, hemodialysis therapy in Wakayama, with the aim of identifying present and future problems.

METHODS

We compared the number of patients on maintenance hemodialysis, patients newly commencing hemodialysis each year, and proportion of diseases prompting the initiation of hemodialysis, between Wakayama and all Japan from 2002 to 2009, using the CD-ROM, "An overview of dialysis treatment in Japan," published by the Japanese Society for Dialysis Therapy.

RESULTS

The number of patients on maintenance hemodialysis per head of population was higher in Wakayama than in all Japan throughout the study period. The number of patients newly commencing hemodialysis per head of population was higher in Wakayama than in all Japan from 2002 to 2004, but no significant difference was seen after 2005. The proportion of patients with chronic glomerulonephritis as the causative disease for hemodialysis initiation was higher in Wakayama than in all Japan. However, nephrosclerosis was less common as the causative condition in Wakayama than in all Japan. The proportions of the different causative diseases were similar in all patients on maintenance hemodialysis in Wakayama as in the newly initiated patients. Accordingly, some patients diagnosed with chronic glomerulonephritis might actually have nephrosclerosis, or treatment may be inadequate.

CONCLUSION

In order to reduce the number of patients requiring maintenance hemodailysis, it is important to accurately differentiate between chronic glomerulonephritis and nephrosclerosis, and also to treat patients with either disease appropriately.

Regional Differences in End-Stage Renal Disease and Amount of Protein Intake in Japan

OBJECTIVE

We recently showed regional differences in the incidence of end-stage renal disease (ESRD) within Japan, which is generally ethnically homogenous, suggesting that factors other than genetic may contribute to the difference. We examined regional differences in the amounts of dietary nutrient intake, especially protein in our search for an explanation.

DESIGN AND SETTING

Annually, the Japanese Society for Dialysis Therapy reports the numbers of patients entering maintenance dialysis in each prefecture of Japan. We used these numbers from 1984 to 2002 to calculate the annual ESRD incidence in each of 12 regions of Japan. The regional differences were analyzed in relation to the amounts of nutrient intake reported annually by National Nutrition Survey in corresponding regions for these 19 years. Each year, approximately 15,000 subjects from 5000 households in randomly selected 300 districts were included to obtain a representative sample of the entire population of Japanese in a manner of age, sex, and body mass matched.

RESULTS

There were marked regional differences in the annual ESRD incidence and small regional differences in dietary intake of each nutrient. Multiple regression analysis showed that the annual ESRD incidence was negatively correlated with energy intake (r = -0.65, F = 240, n = 228) and positively correlated with animal protein intake (r = 0.25, F = 30). Across 12 regions in the values averaged for 19 years in each region, however, the incidence of ESRD was negatively correlated only with the amounts of energy intake (r = -0.74, F = 12, n = 12), but not with animal protein (r = 0.07, F = 0.04).

CONCLUSION

The present study, relating regional differences between ESRD dynamics and the amounts of nutrient intake in a nationwide population of Japan, revealed that the renal protective effects of dietary restriction of protein, suggested by animal models of progressive nephropathies but yet unproved by large-scale clinical trials, remained unestablished even on a macro level of whole Japan through mapping approaches.