Introduction: Aim of this randomized controlled trial was to evaluate the effects of serial locally applied water-filtered infrared A radiation (sl-wIRAR) in patients with axial spondyloarthritis (axSpA).
Methods: axSpA patients with active disease undergoing a 7-day multimodal rheumatologic complex treatment under non-steroidal anti-inflammatory drug (NSAID) therapy were eligible. Patients were randomly assigned in a 1:1 ratio. The intervention group (IG) received additional sl-wIRAR treatment of the back (2 treatments for 30 min per day for 6 days) to assess whether locally applied hyperthermia can i) reduce pain levels, ii) reduce disease activity and improve functionality and iii) whether an effect on tumor necrosis factor α (TNFα) levels is detectable. Additionally, it was examined whether a reduction in NSAID therapy could be achieved after trial completion.
Results: 71 patients completed the trial (IG: 36 patients, control group (CG) 35 patients). sl-wIRAR led to a significant pain reduction measured by a numeric rating scale (p < .0005) and in comparison, to the CG (p = .006). sl-wIRAR treatment resulted in a significant reduction in the Bath Anyklosing Spondylitis Disease Activity Index (BASDAI) (p = .004) and Bath Ankylosing Spondylitis Functional Index (p = .004) with no significant difference to the CG. TNF-α levels were significantly decreased (p = .001) only in the IG with a significant difference to the CG (p = .01). 26 (76%) of patients in the IC reduced their NSAID therapy after trial completion.
Conclusion: sl-wIRAR treatment in axSpA leads to a rapid reduction in pain allowing NSAID dosage reduction. A reason for these desirable effects could be a change in TNFα levels.
Keywords: Hyperthermia; TNF; axSpA; cytokines; physical therapy; wIRAR.