A supported self-help for recurrent depression in primary care; an economic evaluation alongside a multi-center randomised controlled trial

Background Major depression is a prevalent mental disorder with a high risk of relapse or recurrence. Only few studies have focused on the cost-effectiveness of interventions aimed at the prevention of relapse or recurrence of depression in primary care. Aim To evaluate the cost-effectiveness of a supported Self-help Preventive Cognitive Therapy (S-PCT) added to treatment-as-usual (TAU) compared with TAU alone for patients with a history of depression, currently in remission. Methods An economic evaluation alongside a multi-center randomised controlled trial was performed (n = 248) over a 12-month follow-up. Outcomes included relapse or recurrence of depression and quality-adjusted-life-years (QALYs) based on the EuroQol-5D. Analyses were performed from both a societal and healthcare perspective. Missing data were imputed using multiple imputations. Uncertainty was estimated using bootstrapping and presented using the cost-effectiveness plane and the Cost- Effectiveness Acceptability Curve (CEAC). Cost estimates were adjusted for baseline costs. Results S-PCT statistically significantly decreased relapse or recurrence by15% (95%CI 3;28) compared to TAU. Mean total societal costs were €2,114 higher (95%CI -112;4261). From a societal perspective, the ICER for recurrence of depression was 13,515. At a Willingness To Pay (WTP) of 22,000 €/recurrence prevented, the probability that S-PCT is cost-effective, in comparison with TAU, is 80%. From a healthcare perspective, the WTP at a probability of 80% should be 11,500 €/recurrence prevented. The ICER for QALYs was 63,051. The CEA curve indicated that at a WTP of 30,000 €/QALY gained, the probability that S-PCT is cost-effective compared to TAU is 21%. From a healthcare perspective, at a WTP of 30,000 €/QALY gained, the probability that S-PCT is cost-effective compared to TAU is 46%. Conclusions Though ultimately depending on the WTP of decision makers, we expect that for both relapse or recurrence and QALYs, S-PCT cannot be considered cost-effective compared to TAU.