To estimate the future risk and time trends of newly diagnosed venous thromboembolism (VTE) in individuals with incident systemic lupus erythematosus (SLE) in the general population.
Using a population-based database that includes all residents of British Columbia, Canada we conducted a study cohort of all patients with incident SLE and up to 10 age-, sex-, and entry-time-matched individuals from the general population. We compared incidence rates of pulmonary embolism (PE), deep venous thrombosis (DVT), and VTE between the two groups according to SLE disease duration. We calculated hazards ratios (HR), adjusting for confounders.
Among 4863 individuals with SLE (86% female; mean age, 48.9 years), the incidence rates (IRs) of PE, DVT, and VTE were 2.58, 3.33, and 5.32 per 1000 person-years, respectively, whereas the corresponding rates in the comparison cohort were 0.67, 0.57, and 1.11 per 1000 person-years. Compared with non-SLE individuals, the multivariable HRs among SLE patients were 3.04 (95% CI: 2.08-4.45), 4.46 (95% CI: 3.11-6.41), and 3.55 (95% CI: 2.69-4.69), respectively. The age-, sex-, and entry-time-matched HRs for PE, DVT, and VTE were highest during the first year after SLE diagnosis [13.57 (95% CI: 7.66-24.02), 11.13 (95% CI: 6.55-18.90), and 12.89 (95% CI: 8.56-19.41), respectively].
These findings provide population-based evidence that patients with SLE have a substantially increased risk of VTE, especially in the first year after SLE diagnosis. Awareness and increased vigilance of this potentially fatal, but preventable, complication is recommended.