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 (−3 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.