Department of Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan.
Diabetes Care. 2010 Aug;33(8):1805-10. doi: 10.2337/dc10-0199.
Cross-sectional studies have reported increased levels of urinary type IV collagen in diabetic patients with progression of diabetic nephropathy. The aim of this study was to determine the role of urinary type IV collagen in predicting development and progression of early diabetic nephropathy and deterioration of renal function in a longitudinal study.
Japanese patients with type 2 diabetes (n = 254, 185 with normoalbuminuria and 69 with microalbuminuria) were enrolled in an observational follow-up study. The associations of urinary type IV collagen with progression of nephropathy and annual decline in estimated glomerular filtration rate (eGFR) were evaluated.
At baseline, urinary type IV collagen levels were higher in patients with microalbuminuria than in those with normoalbuminuria and correlated with urinary beta(2)-microglobulin (beta = 0.57, P < 0.001), diastolic blood pressure (beta = 0.15, P < 0.01), eGFR (beta = 0.15, P < 0.01), and urinary albumin excretion rate (beta = 0.13, P = 0.01) as determined by multivariate regression analysis. In the follow-up study (median duration 8 years), urinary type IV collagen level at baseline was not associated with progression to a higher stage of diabetic nephropathy. However, the level of urinary type IV collagen inversely correlated with the annual decline in eGFR (gamma = -0.34, P < 0.001). Multivariate regression analysis identified urinary type IV collagen, eGFR at baseline, and hypertension as factors associated with the annual decline in eGFR.
Our results indicate that high urinary excretion of type IV collagen is associated with deterioration of renal function in type 2 diabetic patients without overt proteinuria.
横断面研究报道，糖尿病肾病进展的糖尿病患者尿型 IV 胶原水平升高。本研究旨在确定尿型 IV 胶原在预测早期糖尿病肾病的发展和进展以及肾功能恶化中的作用。
本研究纳入了 254 名日本 2 型糖尿病患者（185 名患者尿白蛋白正常，69 名患者尿微量白蛋白），进行了一项观察性随访研究。评估了尿型 IV 胶原与肾病进展和估计肾小球滤过率（eGFR）的年下降率之间的关系。
基线时，微量白蛋白尿患者的尿型 IV 胶原水平高于尿白蛋白正常患者，与尿β2-微球蛋白（β=0.57，P<0.001）、舒张压（β=0.15，P<0.01）、eGFR（β=0.15，P<0.01）和尿白蛋白排泄率（β=0.13，P=0.01）呈正相关。在随访研究（中位随访时间 8 年）中，基线时尿型 IV 胶原水平与向更高阶段的糖尿病肾病进展无关。然而，尿型 IV 胶原水平与 eGFR 的年下降率呈负相关（γ=-0.34，P<0.001）。多变量回归分析确定了尿型 IV 胶原、基线时的 eGFR 和高血压是与 eGFR 年下降率相关的因素。
我们的结果表明，在没有明显蛋白尿的 2 型糖尿病患者中，尿型 IV 胶原的高排泄与肾功能恶化有关。
