Economic Evaluation of Self-Management for Patients with Persistent Depressive Disorder and their Caregivers.

Background: Persistent depressive disorder (PDD; chronic depression) is associated with high personal, economic, and societal burden. Patients with PDD often fail to respond to treatment, despite long-term, intensive care, suggesting that future treatment should focus more on functional recovery. The "Patient and Partner Education Program for All Chronic Diseases-Persistent Depressive Disorder" (PPEP4All-PDD) is a brief self-management program for patients with PDD with nine weekly sessions, provided in group or individual format. Its focus on functional recovery may increase quality of life and shorten treatment duration, thus reducing healthcare and societal costs. This study examined the cost-effectiveness of PPEP4All-PDD for adults and elderly with PDD and their partners/caregivers compared to care-as-usual (CAU).

Aims of the study: In this economic evaluation, we examined whether a favorable cost-utility of PPEP4All-PDD compared to CAU could be attained.

Method: In this multicenter pragmatic randomized controlled trial, 70 patients with PDD and 14 partners/caregivers were included. Data were collected at 0, 3, 6, and 12 months. Health-related quality of life was measured using the EuroQoL 5-Dimensions/Levels (EQ-5D-5L). Cost of healthcare utilization and productivity loss were assessed using the Trimbos questionnaire for Costs associated with Psychiatric illness (TiC-P). We examined incremental costs per quality-adjusted life years (QALYs) after one year.

Results: In relation to PPEP4All-PDD, 62% (n = 23) of patients had no participating PPEP4All-PDD partner/caregiver, and 89% (n = 33) of patients participated in group format. On average, PPEP4All-PDD cost €232 including the PPEP4All-PDD partner/caregiver, or €166 excluding the partner/caregiver. There was no statistical difference in mean costs per patient for (mental) healthcare, non-healthcare, and societal costs nor in QALYs between PPEP4All-PDD and CAU. The probability that PPEP4All-PDD is cost-effective compared to CAU remained below 50% for all acceptable values of willingness-to-pay for a QALY.

Discussion: This was the first economic evaluation of PPEP4All-PDD. Compared to CAU, PPEP4All-PDD did not lead to lower total healthcare costs nor higher quality of life in the one-year follow-up period. PPEP4All-PDD patients continued to receive additional mental healthcare sessions, showing that the process of ending treatment after a self-management intervention is not clear. The COVID-19 situation may have also affected this process after PPEP4All-PDD, due to higher levels of anxiety and loneliness. We could not confirm that involvement of the partner/caregiver was beneficial to patient treatment outcomes and requires further examination.

Implications: This economic evaluation failed to find significant differences in costs between PPEP4All-PDD and CAU over a study period of one year. Non-significant differences were in favor of CAU, leading to a low probability of PPEP4All-PDD being cost- effective. Providing biweekly sessions and extending the follow-up period may be necessary in future studies. Patients with PDD may require more time to learn and integrate self-management practices into their daily life prior to effecting changes in personal quality of life and (mental) healthcare utilization. Digital interventions, such as digital PPEP4All-PDD, with or without the partner/caregiver may be a cost-effective option.