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

Background and aims: Painful 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.

Methods

In 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.