Elevated N-acetyl-β-D-glucosaminidase, a urinary tubular damage marker, is a significant predictor of carotid artery atherosclerosis in type 1 diabetes, independent of albuminuria: A cross-sectional study

Aims: Recent evidence has shown that renal tubulointerstitial injuries play an important role in diabetic nephropathy. In this study, we evaluated the association between urinary N-acetyl-β-D-glucosaminidase (uNAG), an early renal tubular damage marker, and carotid artery atherosclerosis in patients with type 1 diabetes (T1D). Methods: This was a cross-sectional study of 88 patients with T1D. Demographic and laboratory data; urinary indices, including urinary NAG-to-creatinine ratio (uNCR), and albumin-to-creatinine ratio (uACR); and carotid ultrasonography were investigated. Results: Eighty-eight subjects were divided into three groups based on uNCR tertiles. Subjects belonging to the highest tertile of uNCR had the highest average mean and maximum carotid intima-media thickness (IMT). An elevated uNCR was also significantly correlated with increased average mean and maximum carotid IMT, whereas an elevated uACR was not. Even after adjusting for confounding factors, uNCR continued to be a meaningful predictive marker for increased average mean and maximum IMT. Conversely, the uACR could not predict carotid IMT after adjustment for confounding factors. Conclusions: Elevated levels of uNAG are significantly associated with carotid artery atherosclerosis in patients with T1D independently of albuminuria, a marker of glomerular damage.