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

Abstract 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.