Haptoglobin (Hb) and adiponectin are antioxidant proteins and independent predictors of atherosclerotic vascular disease in diabetic patients. The link between Hp phenotype and circulating adiponectin levels were examined.

Diabetic patients were divided into two groups by Hp phenotype: Hp 2-2 group and non-Hp 2-2 group (Hp2-1 and Hp 1–1). Blood glucose, HbA1C, insulin, lipids, CRP, HOMA-IR, 25OH vitamin D, leptin and adiponectin levels were measured. Pulse wave velocity (PWV) was performed using SphygmoCor (version 7.1, AtCor Medical, Sydney, Australia).

PWV was significantly higher in patients homozygous for the 2 allele (Hp 2-2) compared to non-Hp 2–2 patients (Hp 1-1 and Hp 1–2), p<0.0001. Adiponectin was significantly lower in Hp2-2 patients than in non-Hp 2-2 group (p<0.016). Neither leptin nor the leptin adiponectin ratio (LAR) differed significantly between groups.

PWV was significantly higher and plasma adiponectin levels were significantly lower in diabetic patients homozygous for the 2 allele (Hp 2-2). These differences were detected despite the lack of by-phenotype differences in glycemic control, blood pressure level or presence of cardiovascular risk factor and suggest an active role of adiponectin in the pathophysiology of vascular disease in this patients population.