Increased risk of venous thromboembolism in patients with granulomatosis with polyangiitis: A population-based study.

We assessed the risk and time trends of venous thromboembolism (VTE) including pulmonary embolism (PE) and deep venous thrombosis (DVT) in new granulomatosis with polyangiitis (GPA) cases compared to the general population. Using a population-level database from the entire province of British Columbia, Canada, we conducted a matched cohort study of all patients with incident GPA with up to ten age-, sex-, and entry time-matched individuals randomly selected from the general population. We compared incidence rates of VTE, PE, and DVT between the two groups, and calculated hazard ratios (HR), adjusting for relevant confounders. Among 549 individuals with incident GPA (57.6% female, mean age 55.4 years), the incidence rates for VTE, PE, and DVT were 7.22, 2.73, and 6.32 per 1,000 person-years, respectively; the corresponding rates were 1.36, 0.74, and 0.81 per 1,000 person-years among the 5,490 non-GPA individuals. Compared with the non-GPA cohort, the fully adjusted HRs among GPA patients were 2.90 (95% CI, 1.10-7.64), 4.70 (95% CI, 1.74-12.69), and 1.66 (95% CI, 0.52-5.27) for VTE, PE, and DVT, respectively. The risks of VTE, PE, and DVT were highest during the first year after GPA diagnosis with HR (95% CI) of 11.04 (1.37-88.72), 26.94 (4.56-159.24), and 2.68 (0.23-31.21), respectively. GPA patients are at significantly increased risk of PE, but not DVT. Monitoring for these complications is particularly warranted in this patient population, especially early after diagnosis.