β-trace protein, a new marker of GFR, may predict the early prognostic stages of patients with type 2 diabetic nephropathy

The relationship between serum levels of beta-trace protein (BTP) or serum creatinine (s-Cr) and the prognostic stages of type 2 diabetic nephropathy was determined. Serum samples from 174 patients with type 2 diabetes were obtained from Juntendo University Hospital, Tokyo, and Juntendo Urayasu Hospital, Chiba, Japan. They were classified into four groups according to the Report of the Ministry of Health and Welfare of Japan (1991, p 251-256) as follows: Stage I (normoalbuminuric stage), Stage II (microalbuminuric stage), Stage IIIA (macroalbuminuric stage without renal dysfunction), Stage IIIB (macroalbuminuric stage with renal dysfunction), and Stage IV (renal failure stage). Among these patients, 68 were Stage I, 29 Stage II, 32 Stage IIIA, 17 Stage IIIB, and 28 Stage IV. Levels of serum BTP were measured using the nephelometric assay on a BNA II analyzer (Dade Behring Diagnostics, Marburg, Germany). The mean levels of serum BTP in Stage IIIA were significantly higher than those in Stage I or II (P < 0.00001, P < 0.002, respectively). However, the mean levels of s-Cr in Stage IIIA were not significantly higher than that in Stage I or II. In conclusion, serum BTP was a good marker for the identification of early renal impairment in type 2 diabetes. (C) 2004 Wiley-Liss, Inc.