Clinical Effectiveness and Cost-Effectiveness of Blended Treatment for Major Depression Compared With Treatment as Usual Within Routine Care in Europe: A Noninferiority Randomized Controlled Trial

Abstract Background Cognitive behavioral therapy (CBT) is an effective and widely used treatment for major depressive disorder (MDD). However, access is limited by long waiting lists and a shortage of trained therapists. Evidence-based guided and self-guided digital interventions can address these challenges, but their large-scale adoption in routine primary and specialized mental health care has been slow. Blended CBT (bCBT), combining face-to-face therapy with structured, guided digital treatment modules, may increase treatment capacity while maintaining the benefits of therapist support. Objective The European Comparative Effectiveness Research on Internet-based Depression Treatment study, conducted across 9 European countries, is the first large-scale comparative bCBT study for MDD. The hypothesis was that bCBT is clinically noninferior and cost-effective when compared with treatment as usual (TAU), which mainly consisted of face-to-face CBT. Methods A multisite randomized controlled trial was conducted with a noninferiority margin of d =0.20. Main inclusion criteria were age ≥18 years, a diagnosis of MDD based on the Mini International Neuropsychiatric Interview, and a baseline Patient Health Questionnaire-9 (PHQ-9) score of ≥5. The primary outcome was the PHQ-9, with secondary outcomes including MDD remission at 12 months, therapeutic alliance, and costs. Intention-to-treat analyses were performed, and linear mixed modeling was used to assess intervention effects. Cost-effectiveness analyses were conducted from a health care perspective. Results A total of 835 patients were included in the study. bCBT was shown to be noninferior to TAU on the primary PHQ-9 outcome during treatment (3 months after the baseline assessment, d =−0.26, 95% CI −0.43 to −0.09), at 6 months (posttreatment, d =−0.21, 95% CI −0.39 to−0.04), and at 12-month follow-up ( d =−0.01, 95% CI −0.19 to 0.17). Furthermore, the bCBT group had a significantly lower likelihood of experiencing an MDD episode at 12 months (odds ratio 0.67, 95% CI 0.45‐0.99). Subgroup analyses indicated that participants with and with no antidepressant use at baseline in both groups benefited equally from their treatment. Deterioration rates (Reliable Change Index) were below 5% in both groups. bCBT appeared acceptable for patients and therapists, with a strong working alliance in both groups. From a health care perspective, bCBT was not cost-effective at 12 months' assessment, as its total costs were not significantly lower than TAU. However, the probability that bCBT is cost-effective is high (0.95) at a willingness to pay (WTP) of €3800 per improvement in the PHQ-9 score, and 0.76 at a WTP of €10,000 per MDD case prevented (average 2017 exchange rate was €1=US $1.13). Conclusions bCBT offers an effective and safe digitally supported alternative to face-to-face TAU for patients with MDD and their therapists in routine clinical care. From a health care perspective, its cost-effectiveness depends on policymakers’ WTP for the additional clinical benefits achieved.