Flares Common in Ankylosing Spondylitis
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By Nancy Walsh, Contributing Writer, MedPage Today
Published: May 05, 2010
Reviewed by Dori F. Zaleznik, MD; Associate Clinical Professor of Medicine, Harvard Medical School, Boston and
Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner
Disease flares are common among patients with ankylosing spondylitis, and their pattern may reflect the severity of underlying disease, a British study suggested.
In a cohort of patients with radiologically proven involvement of the sacroiliac joints, 70% reported experiencing a flare in any given week, according to Roxanne Cooksey, PhD, and colleagues from Swansea University in Wales.
"The subjective reporting of flares correlated with a validated measure of disease activity [the Bath Ankylosing Spondylitis Disease Activity Index], which increased by 50% to 90% in minor/localized flare and by 90% to 250% in major/generalized flare," the investigators wrote online in Rheumatology.
The natural history of this chronic inflammatory disease, which primarily affects the spine and sacroiliac joints but may also involve the peripheral joints, eyes, and bowel, remains poorly characterized.
The course of disease varies considerably among patients, with most affected individuals reporting periods of partial remission as well as flares.
However, little is known about the frequency or severity of these flares, as well as their relation to the underlying disease.
To answer these questions, Cooksey and colleagues recruited 134 patients from a study of probiotics in ankylosing spondylitis who completed an online questionnaire each week for three months.
Participants were asked if they had experienced a localized/minor flare (pain and swelling localized to one area, fatigue, and stiffness) or a generalized/major flare (widespread pain, hot burning joints, muscle spasm, fever, sweating, extreme fatigue, and stiffness) during that week.
They also completed the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and the Bath Ankylosing Spondylitis Functional Index (BASFI), and rated their night pain on a visual analog scale.
A majority of the patients were men. The average age was 44 years and mean disease duration was 21 years.
Mean baseline BASDAI was 3.7 (out of 10), and BASFI was 3.6.
During a total of 1,216 person-weeks of follow-up, the overall flare rate was 71.4 per 100 person-weeks (95% CI 66.8 to 76.3).
In that period there were 146 major flares, for a major flare rate of 12 per 100 person-weeks (95% CI 10.2 to 14.1). There were 723 minor flares as well, for a minor flare rate of 59.4 per 100 person-weeks (95% CI 55.2 to 63.9).
Disease activity and function scores rose significantly, even during minor flares:
Mean BASDAI, from 1.8 to 3.1, for a difference of 1.26 (95% CI 0.95 to 1.6)
Mean BASFI, from 2.5 to 3.1, for a difference of 0.56 (95% CI 0.34 to 0.78)
Night pain, from 1.5 to 2.8, for a difference of 1.3 (95% CI 0.92 to 1.68)
Scores rose further during major flares:
Mean BASDAI, from 2.5 to 5.5, for a difference of 3 (95% CI 2.3 to 3.7)
Mean BASFI, from 3.5 to 5.5, for a difference of 2 (95% CI 1.2 to 2.7)
Night pain, from 2.4 to 5.7, for a difference of 3.3 (95% CI 2.3 to 4.4)
These differences during major flares were all statistically significant and clinically relevant, according to the investigators.
Patients who reported major flares did not differ from those who had only minor flares in terms of age, sex, age at disease onset, or disease duration.
The major flare reporters did, however, have higher scores than others, even when not flaring, with a mean BASDAI of 2.5, versus 1.5 for those without major flares.
Most patients who experienced major flares reported that the exacerbations built up gradually, and lasted on average 2.4 weeks.
"The results suggest that there are differences between the people who experience major flares compared with those who do not," the investigators observed.
It's possible that patients who have these generalized flares already have more severe underlying disease, or are at risk for developing worse disease in the future, they suggested.
"Further research could look at the radiographs and MRI scans of those reporting major flares to investigate if this could be used as a marker to predict future severe disease changes, and thereby help identify people for early aggressive therapy," they wrote.
The authors stated that the study was limited by the absence of clinical definitions of flares, recruitment from a study rather than a referral clinic population, and online self-reports which might not have been completed during flares.
The study was supported by the National Ankylosing Spondylitis Society and the Medical Research Council.
The authors have declared no conflicts of interest.
Primary source: Rheumatology
Cooksey R, et al "Frequency and characteristics of disease flares in ankylosing spondylitis" Rheumatology 2010; 49: 929-32.
Illustration of HLA-B complexed peptide.
I was diagnosed with Ankylosing Spondylitis at 16 years old, I have the genetic marker HLA-B27