NDT Advance Access published online on October 30, 2008
Nephrology Dialysis Transplantation, doi:10.1093/ndt/gfn591
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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
1 Department of Cardiology, Pulmonology and Nephrology 2 Department of Neurology, Hematology, Metabolism, Endocrinology and Diabetes 3 Department of Gastroenterology, Yamagata University School of Medicine, Yamagata, Japan
Correspondence and offprint requests to: Tsuneo Konta, Department of Cardiology, Pulmonology and Nephrology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan. Tel: +81-23-628-5302; Fax: +81-23-628-5305; E-mail: kkonta{at}med.id.yamagata-u.ac.jp
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Abstract |
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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, respecti- vely.
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 µg/g) and renal insufficiency (eGFR <60 mL/ min/1.73 m2) 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.
Keywords: albuminuria; beta 2-microglobulin; general population; renal insufficiency
Received for publication: 24. 1.08
Accepted in revised form: 26. 9.08