Plasma interleukin-6 is associated with coagulation in poorly controlled patients with Type 2 diabetes

Aims We investigated the relationship between interleukin (IL)-6 and coagulation, i.e. whether changes in the plasma IL-6 are associated with those in coagulation markers (D dimer and fibrinogen) after glycaemic control with sulphonylurea or insulin in poorly controlled patients with Type 2 diabetes. Methods We studied 42 patients with Type 2 diabetes, including 19 subsequently treated with sulphonylurea, 23 treated with insulin and 48 control subjects. All patients were in poor glycaemic control and were hospitalized for 3 weeks. At the beginning and end of treatment, we measured plasma concentrations of IL-6, fibrinogen, and D dimer. Results Plasma concentrations of IL-6 and D dimer were significantly higher in diabetic patients than in controls (P < 0.0001 for both). In all patients with diabetes, the plasma concentration of IL-6 decreased significantly (P < 0.001) after treatment. Changes in the plasma IL-6 during hospitalization were positively correlated with those in plasma D dimer and fibrinogen (r = 0.664, P < 0.0001; r = 0.472, P = 0.0042, respectively). Treatment with sulphonylurea or insulin caused a similar fall in the plasma IL-6 concentration with a concomitant decrease in the BMI and an equal improvement in glycaemia. Conclusions In poorly controlled patients with Type 2 diabetes, plasma IL-6 concentrations were reduced significantly even by short-term metabolic control. As changes in the plasma concentrations of D dimer are related to plasma IL-6, plasma IL-6 may reflect a pro-coagulant as well as an inflammatory state in patients with Type 2 diabetes.