Arterial and Venous Thrombosis

Ankylosing Spondylitis May Increase Risk of VTE

Individuals with ankylosing spondylitis (AS) appeared to have an increased risk of developing venous thromboembolism (VTE), particularly within the first year of AS diagnosis, according to study findings.

Research has shown an increased risk of venous events in various types of inflammatory arthritis; however, evidence on whether this risk is also greater among patients with AS is limited, according to Juan Antonio Aviña-Zubieta, MD, MSc, PhD, a senior scientist of rheumatology at Arthritis Research Canada, and lead author of the study.


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“I have spent a number of years studying arterial disease due to inflammatory arthritis,” Aviña-Zubieta told Rheumatology Consultant. “It seemed a reasonable hypothesis that an inflammatory arthritis might affect the venous system in a similar fashion.”

To assess the association specifically between AS and VTE risk, Aviña-Zubieta and colleagues used the British Columbia, Canada, health care database to match cohort analyses of incident pulmonary embolism (PE), deep vein thrombosis (DVT), and overall VTE among individuals with AS, and compared them with the general population without AS.

In all, there were 7190 incident cases of AS; 35 participants had developed PE and 47 had developed DVT.

Participants with AS had a higher incidence rate of PE (0.40 vs 0.79), DVT (0.50 vs 1.06), and overall VTE (0.77 vs. 1.56) per 1000 person-years compared with those without AS.

The adjusted hazard ratios (HRs) were 1.36 for PE, 1.62 for DVT, and 1.53 for VTE. The HRs showed the risks of PE (2.88), DVT (2.20), and VTE (2.10) were highest in the first year of AS diagnosis.

“AS is often slow to be diagnosed. We need greater awareness by primary care physicians of AS,” Aviña-Zubieta said. “It used to be thought of as a disease of males, but it is 50/50, so this is another important point,” he said, adding that earlier referral could lead to earlier diagnosis and treatment. “Lower back pain lasting more than 3 months, waking patients at night, and morning stiffness under age 40 are key symptoms that should prompt to seek medical attention.”

Aviña-Zubieta said the real question is whether or not this can be prevented.

We believe treatment of AS can lower both inflammation and VTE, but the latter has not been proven. That is the next question,” he said.

—Colleen Murphy



Aviña-Zubieta JA, Chan J, De Vera M, Sayre EC, Choi H, Esdaile J. Risk of venous thromboembolism in ankylosing spondylitis: a general population-based study. Ann Rheum Dis. 2019;78(4):480-485. doi:10.1136/annrheumdis-2018-214388.