An internet-based cognitive-behavioral self-management intervention for patients with hand osteoarthritis or fibromyalgia – Two randomized controlled trials

Background: Rheumatic and musculoskeletal diseases have a high burden. We aimed to evaluate the effectiveness of a therapist-guided internet-based cognitive-behavioral therapy (iCBT) on pain coping and secondary physical, psychological, and disease impact outcomes in hand osteoarthritis and fibromyalgia. Method: Two single-center, parallel-group, superiority randomized controlled trials were performed. In one study, 70 adults with hand osteoarthritis visiting a Dutch hospital were randomized to care-as-usual or care-as-usual plus iCBT (each group n = 35; ClinicalTrials.gov: NCT05872633). In another study, 70 adults with fibromyalgia visiting a Dutch fibromyalgia-specialized center were randomized to iCBT (n = 34) or a waitlist (n = 36; ClinicalTrials.gov: NCT06322485). Standardized self-report questionnaires were used at baseline, post-intervention, 6-week, and 3-month follow-up and analyzed with statistician-masked intention-to-treat linear mixed models. The primary endpoint was pain coping at post-intervention. Results: In patients with hand osteoarthritis (mean age = 62.4 ± 7.6), no between-group effect on pain coping was found at post-intervention (p = 0.187; Cohen's d = 0.14), while a small to medium effect favored iCBT at 6-week follow-up (p = 0.039; d = 0.41). In patients with fibromyalgia (mean age = 46.4 ± 11.8), a medium to large improvement in pain coping favoring iCBT at post-intervention (p = 0.003; d = 0.60) was not sustained at follow-up. Between-group small to large improvements were found in secondary outcomes (e.g., well-being, osteoarthritis disability, fibromyalgia pain and impact), predominantly at 3-month follow-up (p ≤ 0.047; 0.30 ≤ d ≤ 0.98). Conclusions: ICBT improved pain coping in fibromyalgia at the primary endpoint, whereas the hand osteoarthritis trial was negative at the primary endpoint. Exploratory secondary findings suggest potential benefits for both conditions but warrant replication, particularly in subgroups with a high disease impact.