Patients with 3 subtypes of spondyloarthritis (SpA) — ankylosing spondylitis (AS), psoriatic arthritis (PsA) and undifferentiated SpA (uSpA) — have a higher risk for the development of cardiac disturbances and for requiring pacemaker implantation than the general population. These results from a prospective, register-based, nationwide population study were recently published in the Annals of the Rheumatic Diseases.
The Swedish researchers examined the association between various forms of SpA and atrioventricular block (AVB) II through III, atrial fibrillation (AF), aortic regurgitation (AR), and subsequent pacemaker implantation, providing hazard ratios (HRs) in addition to incidence rates.
Although AS has been linked with cardiac disease previously, many studies have had small sample sizes and lacked adequate controls, offering conflicting results. The established connection between human leukocyte antigen-B27 and conduction disturbances suggests that PsA and uSpA might also be associated with cardiac disease.
The incidence rates for AVB, AF, AR, and pacemaker implantation were established in 3 cohorts: AS (n=6448), PsA (n=16063) and uSpA (n=5190). Results were age and sex adjusted, and stratified by sex, with incidence rates reported as rates per 1000 person-years.
Incidence rates were highest for AF, with AS at 7.1 (95% CI, 5.6-8.6), uSpA at 6.4 (4.6-8.3), and PsA at 7.4 (6.7-8.0), compared with 5.5 (5.4-5.7) in the general population. Pacemaker implantation was the second highest occurrence, with AS at 2.0 (1.3-3.7), uSpA at 1.5 (0.7-2.2), and PsA at 1.5 (1.2-1.8), vs 1.0 (1.0-1.1) for the general population.
HRs were significantly increased for all SpA subtypes when comparing them with those of the general population cohort. For AF, pacemaker implantation, AVB, and AR, rounded HRs were as follows: AS (1.3, 2.1, 2.3, and 1.9), uSpA (1.3, 1.9, 2.9, and 2.0), and PsA (1.5, 1.6, 1.5, and 1.8).
After stratification by sex, the largest HRs were for AVB in male patients with AS and uSpA.
The authors noted several strengths of their study, including a large sample size, the register-based nature of the work (minimizing selection bias and follow-up loss), and that this was the first study of its kind to compare dysrhythmia and AR risks across SpA subtypes in one setting.
The researchers recognized as potential weaknesses the possible misclassification of diagnoses or outcomes, the potential for lower generalizability secondary to exclusion of less severe cases, a possible detection bias, and a lack of detailed patient information, owing to their reliance on population registers. The investigators also pointed out that ideally, human leukocyte antigen-B27 status should be used when assessing the association between SpA subtypes and cardiac conduction problems, but that such information was unavailable to them.
Clinicians should remain aware of the possibility for AF in patients with SpA and should monitor patients for potential AVB, particularly males with AS or uSpA.
Bengtsson K, Forsblad-D’Elia H, Lie E, et al. Risk of cardiac rhythm disturbances and aortic regurgitation in different spondyloarthritis subtypes in comparison with general population: a register-based study from Sweden [published online December 19, 2017]. Ann Rheum Dis. doi:10.1136/annrheumdis-2017-212189