Treatment of back pain in active axial spondyloarthritis with serial locoregional water-filtered infrared A radiation: A randomized controlled trial

BACKGROUND: Axial spondyloarthritis (axSpA) is an inflammatory rheumatic disease primarily affecting the axial skeleton. OBJECTIVE: To evaluate the short-term effects of locoregional water-filtered infrared A radiation (sl-wIRAR) in the treatment of lower back pain in patients with axSpA. METHODS: Patients with active axSpA with non-steroidal anti-inflammatory drug (NSAID) therapy undergoing a 7-day multimodal rheumatologic complex treatment in an in-patient setting were eligible. Patients were randomly assigned to the intervention group (IG) receiving sl-wIRAR treatment of the back (2 treatments/day for 30 min each for 6 days) or to the control group (CG) receiving no treatment. Primary outcome was a between-group difference in pain after sl-wIRAR therapy measured on a numeric rating scale (NRS) (0 [Formula: see text] no pain, 10 [Formula: see text] worst pain). Secondary outcomes included an assessment of i) the onset and development of analgesic effects and an evaluation of whether sl-wIRAR ii) improved axSpA-specific well-being and iii) influenced serum cytokine levels. RESULTS: Seventy-one patients were enrolled, completed the trial and were analyzed (IG: 36 patients, CG: 35 patients). In the IG, there was a statistically significant change ([Formula: see text] 0.0005) in pain level [NRS] (1.6 [Formula: see text] 1.9 [5; 2]) from baseline (4.1 [Formula: see text] 2.4 [0; 8]) to trial completion (2.6 [Formula: see text] 2.0 [0; 7]) and a significant difference to the CG ([Formula: see text] 0.006). In the IG there was a significant improvement in axSpA-specific well-being (BAS-G) ([Formula: see text] 0.006). A physiologically relevant change in serum cytokine levels could not be observed. CONCLUSION: sl-wIRAR treatment can be useful in the treatment of patients with active axSpA as it leads to a rapid reduction of pain.