Is diabetes mellitus an independent risk factor for venous thromboembolism?: a population-based case-control study.

OBJECTIVE Although diabetes mellitus is reported as a risk factor for venous thromboembolism (VTE), persons with diabetes are frequently hospitalized for medical illness or surgery, or confined to a nursing home, all major VTE risk factors. Consequently, we tested diabetes for an independent association with incident VTE. METHODS AND RESULTS Using Rochester Epidemiology Project resources, we identified all Olmsted County, Minn residents who met objective criteria for incident VTE over the 25-year period, 1976 to 2000 (n=1922), and 1 to 2 resident controls per case, matched on age, gender, and length of medical history (n=2115). Complete medical histories in the community were reviewed for previously identified independent VTE risk factors and diabetes-related variables. We tested diabetes and diabetes complications (retinopathy, nephropathy or neuropathy, and ketoacidosis) as potential VTE risk factors, both alone and after adjusting for VTE risk factors. Univariately, diabetes by clinical diagnosis or by stricter criteria (fasting ambulatory blood glucose >/=140 mg/dL or antidiabetic drug therapy), and diabetes complications, were associated with overall incident VTE. However, after controlling for hospitalization for major surgery or medical illness and nursing home confinement, diabetes was no longer associated with VTE. CONCLUSIONS Diabetes mellitus and diabetes complications are not independent risk factors for incident VTE.