Risk of Pulmonary Embolism and Deep Venous Thrombosis in Systemic Sclerosis: A General Population-Based Study

Objective To determine the risk of venous thromboembolism (VTE) (pulmonary embolism [PE] and deep vein thrombosis [DVT]) in individuals with incident systemic sclerosis (SSc; scleroderma) in the general population. Methods Using a population database that includes all residents of British Columbia, Canada, we conducted a cohort study of all patients with incident SSc and up to 10 age-, sex-, and entry time–matched individuals from the general population. We compared incidence rates of PE, DVT, and VTE between the 2 groups according to SSc disease duration. We calculated hazard ratios (HRs), adjusting for confounders. Results Among 1,245 individuals with SSc (83% female, mean age 56 years), the incidence rates of PE, DVT, and VTE were 3.47, 3.48, and 6.56 per 1,000 person-years, respectively, whereas the corresponding rates were 0.78, 0.76, and 1.37 per 1,000 person-years among 12,670 non-SSc individuals. Compared with non-SSc individuals, the multivariable HRs among SSc patients were 3.73 (95% confidence interval [95% CI] 1.98–7.04), 2.96 (95% CI 1.54–5.69), and 3.47 (95% CI 2.14–5.64) for PE, DVT, and VTE, respectively. The age-, sex-, and entry time–matched HRs for PE, DVT, and VTE were highest during the first year after SSc diagnosis (32.77 [95% CI 6.60–162.75], 8.50 [95% CI 3.13–23.04], and 12.03 [95% CI 5.27–27.45], respectively). Conclusion These findings provide population-based evidence that SSc patients are at a substantially increased risk of VTE, especially within the first year after SSc diagnosis. Increased monitoring for this potentially fatal outcome and its modifiable risk factors is warranted in this patient population.