Do Biologic DMARDs Affect Spinal Fracture Risk in Ankylosing Spondylitis?

Biologic disease-modifying antirheumatic drugs (bDMARDs) appeared to have no medium-term effect on spinal fracture risk related to ankylosing spondylitis, according to a longitudinal multiregistry observational cohort study published in BMJ Open.¹

Studies have demonstrated that the use of bDMARDs is associated with an increase in bone density and reduced progression of spinal ankylosis.^1-4 Given these beneficial effects of bDMARDs, researchers examined the association between treatment with bDMARDs and risk for spinal fracture in patients with ankylosing spondylitis.¹

Using the Swedish Patient Registry and the Swedish Prescribed Drugs Registry, the authors identified 1352 patients with ankylosing spondylitis who received more than 1 prescription of a bDMARD from 2005 to 2014 and matched them with 1352 controls with ankylosing spondylitis who received no bDMARD treatment more than once. Patients in the bDMARD group tended to be older (P <.001), had a higher Charlson Comorbidity Index (P =.008), and received more methotrexate (P <.001) than patients in the control group.

The researchers found that there was no bDMARD treatment effect on spinal fracture-free survival in patients with ankylosing spondylitis at 10-year follow-up. However, male gender (P ≤.001) and Charlson Comorbidity Index score (P ≤.001) contributed significantly to fracture risk in this population.

One of the main limitations of this study was the relatively short follow-up of 10 years to determine both the beneficial and adverse effects of bDMARDs.¹ Future studies reevaluating this cohort are recommended to confirm the findings of the present study. In addition, long-term follow-up of randomized, placebo-controlled studies on bDMARD treatment would provide important data on the treatment effect of spinal fracture incidence and its health economic consequences in patients with ankylosing spondylitis.

“This study suggests that bDMARD [treatment] has no medium-term effect on the risk of spinal fractures related to [ankylosing spondylitis]. Therefore, recommendations for physiotherapeutic guidance for spinal injury prevention are valid even for patients receiving a bDMARD.”^1,5

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References

1. Robinson Y, Olerud C, Willander J. Do biological disease-modifying antirheumatic drugs reduce the spinal fracture risk related to ankylosing spondylitis? A longitudinal multiregistry matched cohort study. BMJ Open. 2017;7:e016548.
2. Maas F, Arends S, Brouwer E, et al. Reduction in spinal radiographic progression in ankylosing spondylitis patients receiving prolonged treatment with TNF-alpha inhibitors. Arthritis Care Res. 2017;69(7):1011-1019.
3. Haroon NN, Sriganthan J, Al Ghanim N, Inman RD, Cheung AM. Effect of TNF-alpha inhibitor treatment on bone mineral density in patients with ankylosing spondylitis: a systematic review and meta-analysis. Semin Arthritis Rheum. 2014;44(2):155-161.
4. Briot K, Roux C. Inflammation, bone loss and fracture risk in spondyloarthritis. RMD Open. 2015;1:e000052.
5. Millner JR, Barron JS, Beinke KM, et al. Exercise for ankylosing spondylitis: An evidence-based consensus statement. Semin Arthritis Rheum. 2016;45(4):411-427.