VTE risk elevated in patients with ankylosing spondylitis
medwireNews: Patients with ankylosing spondylitis (AS) have a significantly increased risk for venous thromboembolism (VTE) compared with the general population, with the risk apparently highest in the first year after diagnosis, study findings indicate.
Juan Antonio Aviña-Zubieta (The University of British Columbia, Vancouver, Canada) and co-investigators say their “results expand on the findings of previous studies that implicate AS with vascular disease and add to the importance of controlling this inflammatory disease.”
They add that the findings “call for awareness of this complication, increased vigilance and preventive intervention by controlling the inflammatory process or by anticoagulation in a high-risk AS population.”
During a mean 6.2-year follow-up, there were 35 cases of pulmonary embolism (PE) and 47 cases of deep vein thrombosis (DVT) among 7190 patients with AS registered in the Population Data BC database, which captures all provincially funded healthcare services in British Columbia.
This equated to incidence rates of 0.79 and 1.06 cases per 1000 person–years for PE and DVT, respectively, and 1.56 cases per 1000 person–years for VTE overall.
By comparison, the corresponding incidence rates among 71,900 age- and sex-matched controls without AS were 0.40, 0.50, and 0.77 cases per 1000 person–years.
The researchers note that, at baseline, individuals with AS had a higher prevalence of risk factors associated with VTE than controls, including hypertension, sepsis, inflammatory bowel disease, fractures, and surgery, as well as higher use of glucocorticoids, hormone replacement therapy, oral contraceptives, aspirin, and cyclooxygenase 2 inhibitors.
After adjustment for these potential confounders, the patients with AS still had significant 62% and 53% increased risks for DVT and VTE, respectively, and a non-significant 36% higher risk for PE, than people in the general population.
Furthermore, an analysis of VTE risk over time suggested that the risk was approximately two to threefold higher among AS patients versus controls during the first year after AS diagnosis, but then fell and stabilized during subsequent years.
However, the results of this analysis were not statistically significant, which the researchers say could be due to the small number of VTE cases, or possibly a reduced number of susceptible individuals over time.
Writing in the Annals of the Rheumatic Diseases, Aviña-Zubieta and co-authors suggest that “[f]uture investigation should clarify the relative contributions of treatment to the risks of PE and DVT in AS.”
They add that additional studies could also investigate whether “subsets of the AS population are at higher risk” and “whether treatment of the inflammatory process can reduce the risk of VTE in AS.”
By Laura Cowen
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