In a non-diabetic Japanese population, the combination of macroalbuminuria and increased urine beta 2-microglobulin predicts a decline of renal function: the Takahata study.
BACKGROUND
Glomerular and tubular damage are important factors in the development of renal insufficiency. However, the interaction of these factors is largely unknown in the non-diabetic Japanese population. To clarify the relationship between renal insufficiency and both glomerular and tubular damage, we conducted a community-based study using albuminuria and urine beta 2-microglobulin as markers of glomerular and tubular damages, respectively.


METHODS
Subjects of this study were 2816 non-diabetic individuals >40 years old in Takahata, Japan. The urine albumin-creatinine ratio (UACR) and urine beta 2-microglobulin-creatinine ratio (UBCR) were assessed from single spot urine. The glomerular filtration rate (eGFR) was estimated using the abbreviated MDRD equation with a Japanese coefficient.


RESULTS
The prevalence of albuminuria (UACR >20 mg/ g in men and >30 mg/g in women), increased UBCR (>300 microg/g) and renal insufficiency (eGFR <60 mL/ min/1.73 m(2)) were 21.0%, 12.5% and 21.7%, respectively, and there was only a small overlap between the three. The mean eGFR was significantly lower in subjects with macroalbuminuria (UACR >200 mg/g in men and >300 mg/g in women) and increased UBCR. No urinary abnormalities were observed in 71.7% of the 611 subjects with renal insufficiency, and were more common in young, women and the non-hypertensive population. The 1-year decline of eGFR was greatest in subjects with an overlap of macroalbuminuria and increased UBCR.


CONCLUSIONS
This study indicated that only a small part of renal insufficiency accompanied increased urine albumin or beta 2-microglobulin in the non-diabetic Japanese population. The combination of macroalbuminuria and increased urine beta 2-microglobulin might predict faster renal deterioration.
Ikeda
Ami
A
Department of Cardiology, Yamagata University School of Medicine, Yamagata, Japan.
Konta
Tsuneo
T
Takasaki
Satoshi
S
Hao
Zhimei
Z
Suzuki
Kazuko
K
Sato
Hitoshi
H
Shibata
Yoko
Y
Takeishi
Yasuchika
Y
Kato
Takeo
T
Kawata
Sumio
S
Kubota
Isao
I
D000328:Adult; D000368:Aged; D000419:Albuminuria / Q000150:complications* / Q000503:physiopathology / Q000652:urine*; D044466:Asian People; D015331:Cohort Studies; D003404:Creatinine / Q000652:urine; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D051437:Renal Insufficiency / Q000453:epidemiology* / Q000473:pathology / Q000652:urine*; D012307:Risk Factors; D001613:beta 2-Microglobulin / Q000652:urine*
D001613:beta 2-Microglobulin; D003404:Creatinine