Effectiveness of low-power laser therapy and low-frequency ultrasound in reducing pain in patients with diabetic polyneuropathy: A randomized controlled trial.

This study aimed to compare the efficacy of low-power laser therapy (LPLT) and low-frequency ultrasound (LFU) in reducing pain and improving quality of life in patients with diabetic polyneuropathy (DPN). A randomized controlled trial was conducted involving 55 patients with DPN, randomly assigned to three groups: LPLT (n = 18), LFU (n = 15), and control (n = 22). The LPLT group received treatments three times weekly for four weeks at 6 J/cm² using 808 nm and 905 nm wavelengths. The LFU group received treatments three times weekly for four weeks at 1 MHz, 0.5 W/cm², and 20% duty cycle. All interventions were administered alongside standard medical care. Baseline and post-intervention assessments included the Michigan Neuropathy Screening Instrument (MNSI) and Quality of Life in Diabetic Neuropathy (QOL-DN) measures. At baseline, significant differences were observed in patient-reported MNSI scores (p = 0.001), with the LPLT group reporting the highest scores. Post-intervention, all groups showed reductions in MNSI scores, but between-group differences were not significant (p = 0.292). The LPLT group exhibited the largest mean reduction (-2.39) in patient-reported MNSI scores, though the change only approached significance (p = 0.057). For QOL-DN, the LPLT group showed the greatest improvement in symptom scores (Mean=-2.55, p = 0.023) and problem scores (Mean=-7.05, p < 0.001). ANCOVA confirmed a significant group effect for QOL-DN problem scores (p = 0.007), with the LPLT group showing significantly greater improvement than controls (p = 0.006). LPLT may have potential for improving quality of life and neuropathy symptoms in DPN patients, but the limited between-group differences indicate that its clinical utility remains uncertain. Larger, multicenter trials with longer follow-up are needed to confirm these preliminary findings and establish clinical relevance.