The percentage of patients with seronegative spondyloarthritis requiring magnetic resonance imaging to meet the Canadian Rheumatology Association/Spondyloarthritis Research Consortium of Canada guidelines for access to anti-tumor necrosis factor treatment.
To determine what percentage of patients would require a magnetic resonance imaging (MRI) scan to qualify for treatment in a Canadian tertiary care setting.
Consecutive patients with established axial seronegative spondyloarthropathy were recruited. Patients completed a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Bath AS Functional Inquiry (BASFI) questionnaire and the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) level were measured. Patients were categorized into groups, those who would qualify for anti-tumor necrosis factor (TNF) agents without an MRI, those who would require an MRI to determine eligibility, and those who would not qualify, even with active inflammation on an MRI.
Twenty-nine patients were recruited in a 1-year period and 12 (41.3%; 95% confidence interval 25.5%-59.3%) would require an MRI to gain access to an anti-TNF agent. Extrapolating published estimates of prevalence of seronegative arthritis and AS and assuming 1/3 will have severe resistant disease, about 9000 patients in Canada would require an MRI to determine eligibility for anti-TNF treatment.
Canada currently ranks 13/22 countries studied in terms of MRI resources per capita. Given the limited MRI resources in Canada, Canadian Rheumatology Association/Spondyloarthritis Research Consortium of Canada guidelines could present an additional barrier to timely treatment in 41% of patients.