Dual-Wavelength Laser Therapy for Painful Diabetic Peripheral Neuropathy: A Randomized, Double-Blind, and Sham-Controlled Trial.

BACKGROUND AND

aimsPainful diabetic peripheral neuropathy (DPN) is common and often inadequately controlled with pharmacological therapy. This study evaluated a clinician-directed, prescription home-use dual-wavelength low-level laser therapy device for temporary relief of painful DPN.

methodsIn this prospective, randomized, double-blind, sham-controlled trial conducted at four independent U.S. clinical sites, 64 adults with painful DPN were randomized 1:1 to active treatment (n = 33) or sham treatment (n = 31). The active device emitted simultaneous 640 red and 405 nm violet coherent laser light. Participants self-administered treatment twice daily for 3 weeks, with each session consisting of 5 min per foot. The primary endpoint was the proportion of participants achieving at least a 30% reduction in visual analog scale (VAS) foot pain score from baseline to Week 3. Secondary outcomes included VAS change, neuropathic pain symptoms, treatment satisfaction, durability through Week 7, adherence, blinding integrity, and safety. Participants were required to maintain a stable analgesic and neuropathic-pain regimen throughout, so the intervention was delivered in addition to existing standard care. The primary endpoint was analyzed in the intent-to-treat population, with single imputation for the four participants who withdrew before receiving a device.

resultsAt Week 3, 72.7% of active-treated participants met the primary responder criterion compared with 32.3% of sham-treated participants, a between-group difference of 40.5 percentage points (95% CI 18.1 to 62.9) (p = 0.0024). Mean VAS reduction was greater with active treatment than sham treatment (-33.4 vs -20.0 points; p = 0.026). Improvements were sustained through Week 7, with favorable symptom trends, higher satisfaction, and no serious device-related adverse events. Improvement on the neuropathic pain symptom inventory was greatest for paresthesia/dysesthesia, paroxysmal pain, and burning pain and was not evident for evoked pain.

interpretationPrescription home-use dual-wavelength laser therapy was well tolerated and produced clinically meaningful short-term reductions in foot pain in adults with painful DPN at four independent clinical sites. Because assessment ended four weeks after treatment completion, the findings support short-term pain relief, and the intervention is best positioned as a complementary, nonpharmacological modality used alongside standard care.

trial registrationClinicalTrials.gov identifier: NCT05291975.