Gender and disease duration can help predict which axial spondyloarthritis patients will develop extra-articular manifestations such as uveitis, or inflammation of the eye, according to new research findings presented this week at the 2016 ACR/ARHP Annual Meeting in Washington.
Spondyloarthritis is an inflammatory form of arthritis that mainly affects the spine, and can also affect the joints of the arms and legs. AxSpA patients often exhibit extra-articular manifestations, such as uveitis, psoriasis and inflammatory bowel disease (IBD).
Using epidemiological data collected in the Ankylosing Spondylitis Registry of Ireland (ARSI), which was established in 2013 and included 564 patients by June 2016, researchers set out to evaluate the prevalence of extra-articular manifestations in an axSpA patient cohort. Their goals included identifying differences in these manifestations in patients in early versus late disease, as well as other characteristics.
"Axial spondyloarthropathy (axSpA) has a very definite association with extra-articular manifestations, which are known to be over-represented in this population," said Gillian Fitzgerald, MD, Rheumatology Specialist Registrar at St. James's Hospital in Dublin, and one of the authors of the study. "Each of these extra-articular manifestations alone has morbidity, and our axSpA patients can often have several of these conditions, in addition to the morbidity from inflammatory back pain. This can have a huge impact on their quality of life, so it is important for us as rheumatologists to understand as much as we can about them. Traditionally, AS was thought to be a disease that almost exclusively affected men. However, more recently this has been shown not to be the case. Women can be affected almost as often as men. Therefore, we are very interested in looking at the gender differences in axSpA, and we specifically wanted to look at whether there are any differences between genders in the prevalence of these extra-articular manifestations."
The researchers performed a standardized, detailed clinical assessment on 564 patients. They measured disease activity using the Bath AS Disease Activity Index (BASDAI), spinal mobility using the Bath AS Metrology Index (BASMI), and function using the Bath AS Functional Index (BASFI). They also collected Health Assessment Questionnaire (HAQ) data, AS Quality of Life (ASQoL) data, and patient-reported data, which included the presence of extra-articular manifestations, from structured interviews. The patients in the study were 78.2 percent male. They had a mean age of 47.1 years, mean disease duration of 20.8 years, mean delay to diagnosis of 8.6 years, and 78 percent fulfilled the modified New York criteria.
The researchers measured overall prevalence of extra-articular manifestations among the study subject and found that 35.5 percent have uveitis, 17.8 percent have psoriasis, and 9.7 percent have IBD. Prevalence of uveitis is significantly higher in women (46.7 percent versus 32.3 percent), those in late disease (39.8 percent versus 21.7 percent), and those with the presence of peripheral arthritis (42.4 percent versus 30.9 percent), according to the study's findings. Non-smokers also had more prevalent uveitis than current or past smokers in the study.
IBD prevalence is significantly higher in women (16.5 percent versus 7.7 percent), and in patients with an elevated C-reactive protein test at baseline (11.9 percent versus 5.8 percent), peptic ulcer disease (21.7 percent versus 8.6 percent) and osteoporosis (23.5 percent versus 8.8 percent). Neither disease duration nor smoking status affected IBD prevalence among these patients. Psoriasis prevalence is not affected by disease duration, gender nor smoking. HLA-B27 status and disease severity measures had no impact on the presence of extra-articular manifestations.
The study shows that being female and having axSpA disease for more than ten years is predictive of uveitis, and being female, having an elevated CRP at baseline and peptic ulcer disease are predictive of IBD.
"As rheumatologists, we adopt a holistic approach with our patients. It is important for us to tackle all aspects of axSPA, including associated conditions," said Dr. Fitzgerald. "Some of these conditions can be obvious, such as extensive psoriasis, but others can be quite subtle, such as mild IBD, where the symptoms can often be attributed to other causes. A lack of knowledge regarding which subsets of patients are more likely to develop these conditions is a key barrier to identifying and treating them. Our findings help us to bridge this knowledge gap. However, more research needs to be done."
By using the data in the expanding ASRI registry, "we hope to delve deeper into the area of extra-articular manifestations and identify further characteristics which can predict their development. This information will benefit all rheumatologists and ultimately improve the management of axSpA patients," she concluded.
Explore further: Spondyloarthritis features can identify axial spondyloarthritis