Use of biological disease-modifying antirheumatic drugs (bDMARDs) does not prevent spinal fractures in patients with ankylosing spondylitis, according to a Swedish population-based study.
Findings from the study, “Do biological disease-modifying antirheumatic drugs reduce the spinal fracture risk related to ankylosing spondylitis? A longitudinal multiregistry matched cohort study,” were published in the journal BMJ Open.
As ankylosing spondylitis (AS) progresses, patients are more susceptible to spinal fractures, even when subjected to minor trauma. Current strategies to prevent these fractures are based on physiotherapy and rehabilitation exercises to improve balance and posture.
There is little evidence if currently available ankylosing spondylitis therapies can affect the incidence of spinal fractures in these patients. But some studies have suggested that bDMARDs such as anti-TNF-a and anti-IL-17A can potentially reduce or delay spinal AS-associated stiffness and improve spinal bone density.
To investigate whether bDMARD treatment could reduce the risk of spinal fractures associated with AS, a research team at Uppsala University in Sweden conducted a nationwide observational study (NCT02840695).
The study included 2,704 patients with ankylosing spondylitis who were registered in the Swedish National Patient Registry and the Swedish Prescribed Drugs Registry between 2005 and 2014. Half of the participants were receiving bDMARD therapy.
An analysis of 10 years of follow-up data found that patients receiving bDMARDs were significantly older, received more methotrexate — a type of immune suppressant — and had a higher risk of mortality than the control group, who were AS patients who received bDMARDs just once in the past or never took them.
Ninety-one patients had a fracture during the study period, 47 of whom were in the bDMARD-treated group.
Patients treated with bDMARDs had a spinal fracture in a median time of 12 years, and those in the bDMARD untreated group had a spinal fracture in a median time of 11 years, after they were diagnosed with AS.
Gender and the presence of secondary diseases — but not treatment with bDMARDs — were found to significantly contribute toward fracture risk in the AS patients.
Male patients had a 2.54 times higher risk of having spinal fractures, and patients with elevated CCI scores — a measurement that predicts 10-year survival in patients with multiple comorbidities — had a 3.02 times higher risk.
“This study suggests that bDMARDs have no medium-term effect on the risk of spinal fractures related to AS,” the researchers wrote. “Therefore, recommendations for physiotherapeutic guidance for spinal injury prevention are valid even for patients receiving bDMARDs.”
Because antirheumatic treatments have long-term effects, additional studies with observational clinical data corresponding to longer periods of time are needed to validate these findings.