Background A positive family history (PFH) of spondyloarthritis (SpA) is considered a risk indicator for the presence of axial spondyloarthritis (axSpA) in patients with chronic back pain (CBP). In the ASAS classification criteria, a PFH of SpA is defined as the presence of any of the following diseases in first- or second-degree relatives: ankylosing spondylitis (AS), acute anterior uveitis (AAU), reactive arthritis (ReA), inflammatory bowel disease (IBD), and psoriasis. It is however not known if a PFH for each of these diseases contributes equally well to making a diagnosis of axSpA in patients presenting with CBP.
Objectives To assess which SpA diseases in family members are associated with HLA-B27 and axSpA in patients with CBP.
Methods The SPACE cohort includes patients with CBP (≥3 months, ≤2 years, onset <45 years) from various European rheumatology centers. DESIR is a French prospective multicenter cohort of patients with inflammatory back pain (IBP; ≥3 months, <3 years, onset <50 years), suggestive of axSpA. Patients underwent a full diagnostic work-up at baseline including MRI and radiographs of sacroiliac joints (local reading), laboratory assessments (e.g. HLA-B27), and assessment of all other SpA features. Patients were asked about the presence of SpA diseases in first- or second-degree relatives (AS, AAU, ReA, IBD, and psoriasis). The associations between a PFH and HLA-B27, sacroiliitis, axSpA diagnosis by the rheumatologist, and fulfilment of the ASAS classification criteria in CBP patients were assessed.
Results In 438 patients from the SPACE cohort and 647 patients from the DESIR cohort, a PFH of AS (odds ratio (OR) 5.9 (3.5–9.9) and OR 3.3 (2.1–5.2), respectively for SPACE and DESIR) and a PFH of AAU (OR 9.8 (3.3–28.9) and OR 21.6 (2.9–160.1)) were significantly associated with presence of HLA-B27 (Table 1).Furthermore, in both cohorts a PFH of AS and a PFH of AAU were positively associated with fulfilment of the ASAS-criteria, but not with sacroiliitis on imaging (data not shown). In SPACE, but not in DESIR, a PFH of AS or AAU was associated with axSpA diagnosis (data not shown). In both cohorts, a PFH of ReA, IBD, or psoriasis was not positively associated with HLA-B27 positivity, sacroiliitis on imaging, axSpA diagnosis or meeting the ASAS criteria for axSpA.
Conclusions In two recent CBP cohorts, a PFH of ReA, IBD, or psoriasis did not contribute to identifying axSpA in CBP patients indicating these family elements may not be very useful for diagnosis. A PFH of AS or AAU however may be useful in finding cases in low prevalence settings as these were correlated with HLA-B27 carriership.
Disclosure of Interest None declared