Effectiveness of the FIBROWALK multicomponent therapy in online and outdoor formats for fibromyalgia: A randomized controlled trial (The On&Out study).

This study evaluated the effectiveness of FIBROWALK multicomponent intervention, delivered online (FIBRO-On) or outdoors (FIBRO-Out), compared to treatment as usual (TAU) in reducing fibromyalgia (FM) severity measured by FIQR, which assesses functional impairment, symptom intensity, and overall impact. A total of 225 individuals with FM were randomly assigned to 12 weeks of FIBRO-On (plus TAU), FIBRO-Out (plus TAU), or TAU alone. Assessments were conducted at baseline, mid-intervention (6 weeks), post-intervention (12 weeks), and 6-months (3 months post-intervention). Results from linear mixed-effects models indicated that FIBRO-On (ꞵ = -10.68, 95% CI = -15.13, -6.23) and FIBRO-Out (ꞵ = -9.91, 95% CI = -14.4, -5.42) were more effective than TAU in reducing FM severity at post-intervention. FIBRO-On (ꞵ = -6.02, 95% CI = -10.78, -1.27) was more effective than TAU in reducing FM severity at 6 months, whereas FIBRO-Out showed no such advantage. No significant differences were observed between FIBRO-On and FIBRO-Out for any clinical measure at any time point. Clinically meaningful improvement was observed in 36.3% of FIBRO-On and 37.2% of FIBRO-Out post-intervention and ∼20% at follow-up. Reductions in psychological inflexibility and kinesiophobia after the intervention mediated the effects of FIBROWALK on FM severity at 6-month follow-up, supporting the inclusion of acceptance and commitment therapy components in future versions. Low dropout rates, minimal adverse effects, and significant improvements across clinical outcomes highlight the feasibility and effectiveness of both formats. These findings support FIBROWALK, particularly FIBRO-On, as a scalable FM intervention. Future research should optimize long-term outcomes and explore personalized treatment delivery. TRIAL NUMBER: NCT05377567. PERSPECTIVE: This study supports the short-term effectiveness of FIBROWALK in both formats, and mid-term reduction of fibromyalgia severity and pain in the online version. Mediation analyses suggest that reductions in psychological inflexibility and kinesiophobia underlie treatment effects. Its feasibility and scalability support potential for broader clinical implementation in fibromyalgia care.