NSAIDs Reduce Bone Marrow Edema in Axial Spondyloarthritis

Six weeks of optimal therapy with nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce signal intensity of bone marrow edema in the sacroiliac joints of patients with axial spondyloarthritis, according to a study published in Arthritis & Rheumatology.

Although the therapy reduced bone marrow edema, it did not significantly reduce mean SPARCC (Spondyloarthritis Research Consortium of Canada) scores, and few participants saw significant reductions in BASDAI (Bath Ankylosing Spondylitis Disease Activity Index) scores.

The researchers used magnetic resonance imaging (MRI) to assess 117 patients with clinical suspicion of axial spondyloarthritis. After this baseline MRI, patients were administered optimal doses of NSAIDs for 6 weeks.

Of the initial 117 study participants, 40 were diagnosed with axial spondyloarthritis with a positive finding of bone marrow edema of the sacroiliac joints on MRI. These 40 were deemed eligible for follow-up, undergoing additional MRI assessment at 6 weeks. Participants completed the Bath Ankylosing Spondylitis Functional Index (BASFI) at baseline and week 6, and they completed the BASDAI every 2 weeks.

To quantify the efficacy of NSAIDs on bone marrow edema and disease activity, the researchers used the SPARCC scoring system. After 6 weeks, the mean reduction in SPARCC scores compared to baseline was only 1.1 units. Only 30% of participants showed a clinically significant difference of ≥2.5 units.

There was a large drop-out rate, with 30% of patients failing to take full-dose NSAIDs over 6 weeks due to either poor adherence or intolerance. The researchers note that the high drop-out rate could affect initiation of anti-tumor necrosis factor (anti-TNF) therapy in this population since it is usually only prescribed after NSAID therapy fails.

At 6-week follow-up, the patients’ bone marrow edema did not appear altered in extent, but intensity significantly decreased: 80% of participants showed high-intensity lesions at baseline, and 62.5% of these participants showed improvement at follow-up.

Currently, the clinical relevance of bone marrow edema intensity is not known. However, it has been correlated with histopathological findings in patients with ankylosing spondylitis.

Reference

Varkas G, Jans L, Cypers H, et al. Six-week treatment of axial spondyloarthritis patients with an optimal dose of NSAIDs: early response to treatment in signal intensity on magnetic resonance imaging of the sacroiliac joints. Arthritis Rheumatol. 2015. doi: 10.1002/art.39474.