High frequency of venous thromboembolic events in Churg-Strauss syndrome, Wegener's granulomatosis and microscopic polyangiitis but not polyarteritis nodosa: a systematic retrospective study on 1130 patients

Objective: To determine the frequency and risk factors of venous thromboembolic events (VTE) in Wegener's granulomatosis (WG), microscopic polyangiitis (MPA) and, the so far unstudied, Churg-Strauss syndrome (CSS) and polyarteritis nodosa ( PAN). Methods: Retrospective, systematic analysis and comparisons were made between the characteristics of patients in the VTE group and non-VTE group. 1130 patients with WG, MPA, CSS or PAN were identified from the French Vasculitis Study Group cohort. Results: During a mean follow-up of 58.4 (45.8) months, 83 VTE occurred in 74 (6.5%) patients, with a median vasculitis-VTE diagnosis interval of 5.8 months ( 23 to + 156). VTE occurred in seven of 285 (2.5%) patients with PAN, 19 of 232 (8.2%) with CSS, 30 of 377 (8%) with WG and 18 of 236 (7.6%) with MPA. Multivariate analysis retained age, male sex or previous VTE or stroke with motor deficit as being associated with a higher VTE risk. The adjusted odds ratio (95% confidence interval) for VTE was 2.88 (1.27 to 6.50) for patients with WG, MPA or CSS compared with PAN (p = 0.01). Conclusions: Our results suggest that, like WG and MPA, patients with CSS are at a greater risk of VTE, than those with PAN. The reasons for this difference remain to be elucidated.