2-5
CKD surveillance in Japan
Iseki K
Dialysis Unit, University Hospital of The Ryukyus, Okinawa, Japan

According to the Japanese Society for Dialysis Therapy, the number of chronic dialysis therapy is more than quarter million and the prevalence is 2018 per million populations at the end of 2005. Among them, Okinawa has the highest prevalence of dialysis patients. Currently, the prevalence is more than 2500 per million populations (total 1.36 million). Such high prevalence and geographical difference are important issues for future research questions. Japanese Society of Nephrology (JSN) has organized the Association for CKDI to promote early detection and prevention of end-stage renal disease (ESRD) in Japan.
We have been studying the renal outcomes of the screened population in Okinawa. The Okinawa General Health Maintenance Association, a nonprofit organization founded in 1972, has been conducting community-based health examination annually. The details of every ESRD patient treated in Okinawa since 1971 are maintained in an independent registry; the Okinawa Dialysis Study (OKIDS). By the end of 2000, we registered a total of 5246 patients. Using the two registries, we identified screening participants who later entered a dialysis program using the two computer registries. Computer-based registry data for the standard analysis are available for the 1983 (n=106171), 1993 (n=143948), and 2003 (n=154019) screenings. Estimated GFR was calculated using the abbreviated MDRD equation. Since there is no known ethnic factor for Japanese, we did not correct the estimated GFR value. Currently, JSN is working to estimate GFR using serum creatinine, sex, and age based on inulin-clearance (E. Imai and S. Matsuo). Significant changes in the participantsﾕ demographics have been observed during the study period. While both systolic and diastolic blood pressure decreased, mean levels of serum cholesterol, triglycerides, and fasting plasma glucose, and the prevalence of overweight and obesity increased. Among the variables studied, dipstick positive proteinuria was the strongest predictor. The Okinawa screening program provides valuable opportunities for the detection of CKD in the general population.
We further analyzed that the prevalence of CKD in patients with obstructive sleep apnea syndrome (OSA) which is often associated with obesity (N=1624). CKD was found in 496 (30.5%) patients, which was higher than that of the general population (15.1%).
High prevalence of CKD among elderly population is not fully explained by ageing process per se. Obesity, metabolic syndrome, and hypertension may underlie for the high prevalence of CKD. More efforts are needed to promote early detection and early intervention for CKD in Japan.