Thrombin generation and factor VIII:C levels in patients with type 1 diabetes complicated by nephropathy

The association between plasma coagulant activity and the presence of diabetic nephropathy was investigated in 31 patients with Type 1 diabetes, 12 with and 19 without nephropathy, and in 11 healthy subjects. Thrombin generation was assessed by computer assisted chromogenic method and expressed as time (in seconds) to 50% maximal thrombin activity (T₅₀). Factor VIII:C levels related to thrombin activity, glycaemic control, and renal function. Median (IQ) FVIII:C concentration was increased in patients with nephropathy (1590 (1130-1900) IU l^-1) compared to those without renal disease and with controls (960 (750-1090); 1020 (810-1100) IU l^-1, p <0.01, respectively). There were no significant differences in T50 values between the groups. FVIII:C correlated with age in all subjects and in the diabetic group (r = 0.33, p = 0.036; r = 0.39, p = 0.031) and inversely with T₅₀ in all subjects and in controls (r = -0.35, p = 0.02; r = -0.62, p = 0.04). In all subjects and in patients, FVIII:C was related to urinary albumin excretion and creatinine clearance. FVIII:C and T₅₀ were not related to HbA_1c. The results show that FVIII:C levels are increased in Type 1 diabetes complicated by nephropathy and are related to degree of renal impairment but not levels of glycaemia. No associated enhancement of plasma procoagulant activity was detected.