Prevalence of chronic kidney disease (CKD) in the Japanese general population predicted by the MDRD equation modified by a Japanese coefficient.
BACKGROUND
The number of patients with end-stage renal disease (ESRD) in Japan has continuously increased in the past three decades. In 2005, 36,063 patients whose average age was 66 years entered a new dialysis program. This large number of ESRD patients could be just the tip of the iceberg of an increasing number of patients with chronic kidney disease (CKD). However, to date, a nationwide epidemiological study has not been conducted yet to survey the CKD population.


METHODS
Data for 527,594 (male, 211,034; female, 316,560) participants were obtained from the general adult population aged over 20 years who received annual health check programs in 2000-2004, from seven different prefectures in Japan: Hokkaido, Fukushima, Ibaraki, Tokyo, Osaka, Fukuoka, and Okinawa prefectures. The glomerular filtration rate (GFR) for each participant was estimated from the serum creatinine values, using the abbreviated Modification of Diet in Renal Disease (MDRD) study equation modified by the Japanese coefficient.


RESULTS
The prevalences of CKD stage 3 in the study population, stratified by age groups of 20-29, 30-39, 40-49, 50-59, 60-69, 70-79, and 80-89 years, were 1.4%, 3.6%, 10.8%, 15.9%, 31.8%, 44.0%, and 59.1%, respectively, predicting 19.1 million patients with stage 3 CKD in the Japanese general adult population of 103.2 million in 2004. CKD stage 4 + 5 was predicted in 200,000 patients in the Japanese general adult population. Comorbidity of hypertension, diabetes, and proteinuria increased as the estimated GFR (eGFR) decreased. The prevalence of concurrent CKD was significantly higher in hypertensive and diabetic populations than in the study population overall when CKD was defined as being present with an eGFR of less than 40 ml/min per 1.73 m(2) instead of less than 60 ml/min per 1.73 m(2).


CONCLUSIONS
About 20% of the Japanese adult population (i.e., approximately 19 million people) are predicted to have stage 3 to 5 CKD, as defined by a GFR of less than 60 ml/min per 1.73 m(2).
Imai
Enyu
E
Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Osaka, 565-0871, Japan. imai@medone.med.osaka-u.ac.jp.
Horio
Masaru
M
Department of Functional Diagnostic Science, Osaka University Graduate School of Medicine, Osaka, Japan.
Iseki
Kunitoshi
K
Dialysis Unit, University Hospital of The Ryukyus, Okinawa, Japan.
Yamagata
Kunihiro
K
Department of Nephrology, Institute of Clinical Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan.
Watanabe
Tsuyoshi
T
Third Department of Medicine, Fukushima Medical University, Fukushima, Japan.
Hara
Shigeko
S
Health Medical Center, Toranomon Hospital, Tokyo, Japan.
Ura
Nobuyuki
N
Second Department of Internal Medicine, Sapporo Medical University School of Medicine, Sapporo, Hokkaido, Japan.
Kiyohara
Yutaka
Y
Department of Environmental Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Hirakata
Hideki
H
Nephrology and Dialysis Center, Fukuoka Red Cross Hospital, Fukuoka, Japan.
Moriyama
Toshiki
T
Healthcare Center, Osaka University, Osaka, Japan.
Ando
Yasuhiro
Y
Department of Nephrology, Jichi Medical School, Tochigi, Japan.
Nitta
Kosaku
K
Department of Medicine, Kidney Center, Tokyo Women's Medical University, Tokyo, Japan.
Inaguma
Daijo
D
Tosei General Hospital, Aichi, Japan.
Narita
Ichiei
I
Division of Nephrology and Rheumatology, Niigata University, Niigata, Japan.
Iso
Hiroyasu
H
Department of Public Health, Osaka University Graduate School of Medicine, Osaka, Japan.
Wakai
Kenji
K
Aichi Cancer Institute, Japan.
Yasuda
Yoshinari
Y
Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Tsukamoto
Yusuke
Y
Syuwa General Hospital, Japan.
Ito
Sadayoshi
S
Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, Miyagi, Japan.
Makino
Hirofumi
H
Department of Medicine and Clinical Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
Hishida
Akira
A
First Department of Medicine, Hamamatsu University School of Medicine, Shizuoka, Japan.
Matsuo
Seiichi
S
Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D003404:Creatinine / Q000097:blood; D004032:Diet; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology; D006306:Health Surveys; D006801:Humans; D007564:Japan / Q000453:epidemiology; D007674:Kidney Diseases / Q000453:epidemiology* / Q000208:ethnology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D015995:Prevalence
D003404:Creatinine