Context: It has been debated whether an increased risk of venous thromboembolism (VTE) exists in patients with Cushing's syndrome.
Objective: We aimed to summarize published literature on the effects of endogenous hypercortisolism on coagulation and fibrinolysis, as well as on the clinical outcome of VTE.
Data sources: We searched the MEDLINE and EMBASE databases up to July 2008. Review of reference lists further identified candidate studies.
Study selection: Two investigators independently performed study selection and data extraction. Eligible studies had to include Cushing's syndrome patients and either evaluate hemostatic parameters in comparison with control persons or posttreatment levels or describe the occurrence of VTE.
Data extraction: The Newcastle-Ottawa Scale was used to assess study quality. A scoring system divided studies into categories of low, medium and high quality.
Data synthesis: Of 441 identified publications, 15 reports were included. They contained information on eight cross-sectionals, two intervention, and eight cohort studies. No high-quality studies were identified. Hypercoagulability was suggested by high levels of factor VIII, factor IX, and von Willebrand factor and by evidence of enhanced thrombin generation. A risk of 1.9 and 2.5% was reported for VTE not provoked by surgery, whereas risk of postoperative VTE varied between 0 and 5.6%, with one outlier of 20%. VTE was reported as the cause of death in 0-1.9% of Cushing's syndrome patients.
Conclusions: Available studies suggest a high risk of venous thrombosis in patients with Cushing's syndrome. Glucocorticoid-induced hypercoagulability as well as surgery and obesity almost certainly contribute to this thrombotic tendency.