LOW-LEVEL LASER THERAPY FOR PAIN REDUCTION IN PSORIATIC ARTHRITIS: A RANDOMIZED CONTROLLED STUDY

D. Munteanu-Covila, E. Russu, L. Groppa | Nicolae Testemitanu State Medical and Pharmaceutical University, Chisinau, Republic of Moldova

Abstract

Background and Aims. Pain remains a dominant and disabling symptom in psoriatic arthritis (PsA), often persisting despite pharmacologic control of inflammation. Low-level laser therapy (LLLT) has emerged as a non-invasive modality with potential analgesic and anti-inflammatory effects. This study aimed to evaluate the efficacy of LLLT in reducing pain in patients with active PsA.
Methods. A randomized, double-blind, placebo-controlled trial included 117 PsA patients. Participants were assigned to active LLLT (n=59) or sham therapy (n=58), administered three times weekly for 8 weeks. Pain intensity was assessed using the visual analog scale (VAS). Secondary outcomes included Disease Activity Score in 28 joints (DAS28) and functional status. Statistical analysis included repeated-measures analysis and between-group comparisons.
Results. At baseline, pain levels were comparable between groups (VAS 62±15 vs. 65±18 mm; p>0.05). After 8 weeks, the LLLT group demonstrated a significantly greater reduction in pain (-42 mm vs. -15 mm;‭ ‬ Δ = -27 mm; p < 0.0001; effect size g = 1.45), corresponding to a 68% decrease from baseline. Clinically meaningful pain reduction (≥20 mm) was achieved in 85% of LLLT patients compared to 30% in the placebo group (p < 0.001; relative risk = 2.83). Pain reduction correlated with improvement in disease activity (ρ=0.48; p=0.002), suggesting an inflammation-mediated mechanism. Repeated-measures analysis confirmed a significant group × time interaction (p < 0.001), indicating a sustained analgesic effect.
Conclusions. Low-level laser therapy provides significant and clinically meaningful pain reduction in PsA. It represents a safe and effective adjunctive strategy for managing persistent pain in inflammatory arthritis.