NEW YORK – Consistent evidence for a substantial increase in cardiovascular events remains elusive for patients with ankylosing spondylitis who have a broad range of CV risk factors.
"We can all agree that the risk factors for cardiovascular disease are higher in patients with AS [ankylosing spondylitis], but I think it is more controversial whether every AS patient faces a higher risk of events," observed Dr. Lianne Gensler, director of the ankylosing spondylitis clinic at the University of California, San Francisco.
Dr. Lianne Gensler
Although this statement was made in reference to ischemic heart disease, the analysis presented by Dr. Gensler at the joint meetings of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis and the Spondyloarthritis Research & Treatment Network appears to be relevant to valvular disease, arrhythmias, and left ventricular dysfunction. Other CV risk factors associated with AS include hypertension, aortic insufficiency, and conduction disorders.
Inconsistencies in studies of CV
The obstacle for drawing conclusions is the lack of consistency in the published studies that relate specifically to AS but are independent of other inflammatory joint diseases, such as rheumatoid arthritis. In a review, Dr. Gensler cited one meta-analysis of 17 studies published in 2011 that did not associate AS with increased CV events (Arthritis Care Res. 2011;63:557-63). Although several studies published subsequently did associate AS with an increased rate of events, there were others that did not.
In an analysis that was performed at her institution based on AS patient data from the Healthcare Cost and Utilization Project National Inpatient Sample, no difference could be found in in-hospital mortality due to CV events when AS patients were compared with non-AS patients stratified by age.
In regard to CV structural disease related to AS, there is substantial evidence that several abnormalities are more common in AS, but there is far less to document that these lead to an increased risk of events. For example, Dr. Gensler cited one study in which the prevalence of aortic insufficiency climbed from 2% in patients with 10 years’ AS duration to 12% in those with 30 years. In another, inflammation of the septum, a potential risk for conduction disorders, climbed from 3% to 90% in AS patients followed long-term.
Asymptomatic conduction disorders
Conduction disorders in general – and QRS disturbances in particular – have been commonly reported in AS patients, but typically in the absence of symptoms, according to Dr. Gensler. She cited one electrocardiogram study in which 30% of AS patients had QRS prolongation, but all were asymptomatic. In another study of 200 AS patients, conduction disorders were found in 33%, of which atrioventricular block was the most common. In this study, increased markers of inflammation did not correlate with conduction disorders in a multivariate analysis.
"Whether we should be doing anything to look for these [conduction disorders] when they do not have symptoms is a question that I will put out to the audience," Dr. Gensler said.
Effect of treatment on CV events
The effect of AS therapies, particularly tumor necrosis factor (TNF) inhibitors, on CV risk also remains incompletely understood. In one study cited by Dr. Gensler, improved endothelial function was observed in AS patients treated with a TNF inhibitor, suggesting a potential protective effect, but, again, no difference in event rates in AS patients has ever been documented between those on TNF inhibitors and those not on TNF inhibitors.
Overall, more data are needed to determine the effect of AS on the risk of CV events, but one risk factor deserves attention even if there is no specific evidence that it affects CV events, according to Dr. Gensler.
In AS, "we know that smoking is a risk for early-onset disease, more inflammation, more damage, and more progression, so I think this [smoking cessation] is one guideline we can take to heart and take home to our patients," she said.
Dr. Gensler reported financial relationships with UCB and AbbVie.