Less than one-third of patients with new-onset inflammatory back pain were found to progress to spondyloarthritis during a 13-year period; most resolved to inflammatory back pain in a study published in Arthritis and Rheumatology.
Inflammatory back pain is commonly considered an early manifestation of spondyloarthritis. However, a direct link between the two has not been confirmed, as little is known about the long-term clinical outcomes of patients with inflammatory back pain.
Researchers conducted a retrospective population-based study in which patients experiencing new-onset inflammatory back pain (age, 16-35 years) were assessed after a median follow-up of 13.2 years.
Of the 124 participants (82 men, 42 women), 39 progressed to spondyloarthritis, 15 had an alternate diagnosis, and 58 had resolution of inflammatory back pain. At the 10-year mark, the probability in this cohort of having spondyloarthritis was 30%, whereas the probability of resolution of inflammatory back pain was 43%.
A history of uveitis, male sex, and family history of spondyloarthritis were found to be the most important predictors of progression to spondyloarthritis, using a recursive partitioning model. This is consistent with the notion that the risk for developing spondyloarthritis is largely genetically determined.
The investigators noted several limitations of the study that were a result of its retrospective nature, including patient accommodation to back pain symptoms, which could have caused an overestimation of resolution, and potential omission and misclassification of patients because of varying degrees of symptoms.
“Our findings indicate that while [inflammatory back pain] can be a precursor of [spondyloarthritis], the presence of [inflammatory back pain] is not a predestination to [spondyloarthritis],” concluded the authors, adding “[Inflammatory back pain] is more accurately considered a symptom complex of a specific type of arthralgia that may or may not be associated with [spondyloarthritis,] and may be self-limited.”
Wang R, Crowson C-S, Wright K, Ward M-M. Clinical evolution of patients with new-onset inflammatory back pain: a population-based cohort study [published online February 22, 2018]. Arthritis & Rheumatology doi: 10.1002/art.40460