Significance of detecting urinary type IV collagen in diagnosis of early diabetic nephropathy in type 2-diabetic patients

Objective To investigate the role of detection of urinary type IV collagen in diagnosis of early type 2-diabetic nephropathy and effective factors. Methods Sixty patients with type 2-diabetes were chosen in our hospital from 2000-03-2000-12 and were divided into three groups by the rate of urinary microalbumin,and twenty healthy people as the control group.Urinary type IV collagen was determined with enzyme-linked immunosorbent assay, urinary microalbumin with immunoturbidimetry,blood glucose,the insulin-sensitivity index, 24 h ambulatory blood pressure,plasum lipid and some corresponding factors of renal functions were measured at the same time.Results The urinary type IV collagen content was ( 1.93± 1.12) mg/L in the control group, ( 6.61± 1.64) mg/L in diabetic with normal nephropathy group, ( 11.35± 3.76) mg/L in early-stage diabetic nephropathy group and ( 23.40± 13.8) mg/L in clinical-stage diabetic nephropathy group.It was higher in the group of normal microalbuminuria diabetic patients than in the control(P 0.05) while urinary albumin rate was close to between them (P 0.05),the urinary level of type IV collagen was markedly higher in early-stage and clinical-stage diabetic nephropathy patients than in the control(P 0.01).The insulin-sensitivity index was lower in three diabetic groups than in the control(P 0.05).Mean blood pressures including 24 hours, nocturnal time and diurnal time were higher in clinical-stage diabetic nephropathy group than in other three groups(P 0.05).There was significantly positive correlation between urinary type IV collagen and diabetic duration,urinary albumin rate,urinary α 1-microglobulin,urinary β 2-microglobulin, past blood glucose,24-hour mean diastolic pressure,nocturnal blood pressure,nitrogen-acetyl-β-glucosaminidase.The urinary IV collagen was also negatively related to the insulin-sensitivity index(P 0.05). Conclusion Urinary type IV collagen is a sensitive indicator in diagnosis of early diabetic nephropathy and monitoring the progression of diabetic nephropathy while reflecting the degree of renal lesion.