Significantly higher risk of stroke tied to ankylosing spondylitis

Analysis pools data from 11 studies involving some 1.7 million people

Steve Bryson PhD avatar

by Steve Bryson PhD |

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People with ankylosing spondylitis (AS) are at a significantly higher risk of stroke — a 56% greater risk — than those without this disease, according to a pooled analysis of 11 published studies involving more than 1.7 million participants.

Management of stroke risk factors and control of systemic (bodywide) inflammation should be considered in AS patients, the researchers suggested.

The study, “Increased risk of stroke among patients with ankylosing spondylitis: A systematic review and meta-analysis,”was published in the journal Reumatología Clínica.

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Particular risk for ischemic stroke, due to blocked vessels supplying the brain

AS is a type of inflammatory arthritis that affects the spine and the sacroiliac joints, where the base of the spine connects with the pelvis.

Among its complications, AS is associated with a higher risk of a heart attack and cardiovascular-related mortality. As a result, the European Alliance of Associations for Rheumatology recommends patients have an annual risk assessment for cardiovascular disease.

An international group of researchers conducted a pooled analysis of studies published between 2006 and 2021 to investigate the risk of stroke in people with AS.

Most strokes are caused by blockages in blood vessels that supply the brain and called ischemic stroke, while hemorrhagic stroke is caused by bleeding in the brain.

Eleven studies matched their criteria: those that evaluated stroke risk among AS patients, with appropriate design and reporting of results.

Selected studies were conducted in Germany, Sweden, Korea, Taiwan, Canada, the U.K., and the U.S. Overall, more than 1.7 million participants were enrolled, both men and women, with an average follow-up of 11 years.

Across all studies, about 26,000 strokes were reported. The pooled analysis found that the overall risk of stroke was 56% higher in AS patients compared with control groups of people without this disease, a statistically significant difference.

The risk of ischemic stroke, in particular, was 46% higher in AS patients. One study reported a 2.72 times higher risk of hemorrhagic stroke in these patients; it was one of two studies that investigated this type of stroke.

Disease duration was not related to stroke risk. A study’s location — across North America, Europe, and Asia — also showed no association with risk. Stroke risk in studies published between 2006-2012 was 47% higher among AS patients, and risk was 66% higher in studies published after 2012.

“Our data support the hypothesis that AS is a significant risk factor for stroke,” the researchers wrote.

This elevated risk may be due to high blood pressure or the use of anti-inflammatory drugs as first-line AS treatments, they suggested. In addition, AS patients typically have a poorer cardiovascular profile, with a higher incidence of metabolic syndrome, a risk factor for cardiovascular disease, and for these reasons are more likely to have diabetes and/or high blood pressure.

There was a high degree of heterogeneity across selected studies, which are differences that arise when comparing them, such as a study’s design or size.

Statistical analysis, however, confirmed a low risk of publication bias across selected studies. Publication bias occurs when the outcome of a study influences the decision to publish, thereby only publishing positive results.

Still, researchers urged caution in interpreting the results due to variations in the sample sizes and “differences in the patient characteristics.” For example, one U.K. study included over 1.2 million participants, more than all of the other studies combined.

“This study suggests that ankylosing spondylitis significantly increases the risk of stroke,” the team concluded. “Management of cerebrovascular risk factors and control of systemic inflammation should be considered in patients with ankylosing spondylitis.”