As serum beta-2-microglobulin (B2M) levels are usually elevated in patients with renal failure, they have been suggested as a surrogate marker of cardiovascular mortality for patients with chronic kidney disease. Glycation of B2M is cytotoxic and may contribute to the risk of diabetic complications in patients with diabetes. Our objective was to evaluate the relationship between B2M and diabetic complications in patients with type 2 diabetes (T2D) and normal kidney function.

A total of 366 patients with T2D and preserved renal function with no clinical evidence of cardiovascular disease were enrolled consecutively into this study. High B2M was defined as a median serum B2M level ≥ 1.8mg/L. Subclinical atherosclerosis was defined as a carotid artery intima–media thickness (C-IMT) ≥ 0.9mm or the presence of carotid plaque. The definition of diabetic nephropathy was based on the presence of albuminuria (≥ 30mg/g creatinine).

Patients with high B2M were older, and had diabetes of longer duration, higher serum creatinine, microalbuminuria, and increased vascular stiffness and C-IMT compared with patients with low B2M. B2M levels were positively correlated with C-IMT and vascular stiffness, and these associations remained constant after adjusting for age. In addition, after adjusting for age, gender, body mass index, serum creatinine, hypertension, smoking and alcohol consumption, the adjusted odds ratio (OR) for atherosclerosis was 2.01 [95% confidence interval (CI): 1.02–3.94] per 1mg/L increase in B2M. The prevalences of diabetic retinopathy and nephropathy were significantly higher with a high B2M than with a low B2M. The multiple adjusted OR for diabetic nephropathy was 2.29 (95% CI: 1.11–4.72) per 1mg/L increase of B2M.

Higher serum B2M was an independent risk factor for subclinical atherosclerosis and diabetic nephropathy in patients with T2D without renal impairment.