Eye, Skin, Bowel Signs Predate AS Diagnosis

Carmen Stolwijk C, Ivette Essers I, van Tubergen A, et al., The epidemiology of extra-articular manifestations in ankylosing spondylitis: a population-based matched cohort study. Ann Rheum Dis  (2014) doi:10.1136/annrheumdis-2014-205253

Three key clues signal possible ankylosing spondylitis (AS) in patients with inflammatory back pain, a large population study suggests. These are:

•  acute anterior uveitis (AAU),
•  psoriasis, and
•  inflammatory bowel disease (IBD).

These extra-articular manifestations of AS, particularly uveitis, are often present before AS diagnosis. In this study, 11.4% of AS patients had AAU at first diagnosis.

The study compared 4,101 AS patients with 28,591 controls from the Clinical Practice Research Datalink (CPRD), a large UK medical records database, from 1989-2012. The AS patients showed a 16-fold increase in AAU prevalence.

Risks for psoriasis and IBD were lower compared to controls, at 150% and 330%, respectively. Also, fewer patients had these conditions at  diagnosis of AS (4.4% had psoriasis and 3.7% had IBD). \

The prevalence of extra-articular manifestations roughly doubled within 20 years of diagnosis, to 25% for AAU, 10% for psoriasis, and 7.5% for IBD.

Uveitis is especially common in axial or peripheral spondyloarthritis (SpA) but rare in the general population, making is an important red signal in patients with chronic low back pain, the researchers note. Psoriasis and IBD should also raise suspicion for SpA.