Complaint-Directed Mini-Interventions for Depressive Symptoms: A Health-Economic Evaluation of Unguided Web-Based Self-Help Interventions (Preprint)

BACKGROUND The past decades depression prevention and early intervention has become a top priority within the Netherlands, however, there is still considerable room for improvement. To this extent, web-based complaint-directed mini-interventions (CDMIs) were developed. These brief and low-threshold interventions focus on psychological stress, sleep problems, and worry, because these complaints are highly prevalent, are demonstrably associated with depression and have a substantial economic impact. OBJECTIVE Aim of the current economic evaluation is to examine the added value of web-based unguided self-help CDMIs as compared to a wait-listed control group with unrestricted access to usual care both from a societal and healthcare perspective. METHODS This health economic evaluation was embedded in a randomized controlled trial. The study entailed two-arms in which three web-based CMDIs were compared to a no-intervention waiting-list control group (control group received intervention at three months follow-up). Measurements were conducted at baseline, and at three- and six-months follow-up. Primary outcome of the study was response rate on depressive symptomatology as measured by the Inventory of Depressive Symptomatology Self-Report (IDS-SR). Change in quality of life was estimated by calculating effect sizes (Cohens’ d) for individual pre- and post-treatment IDS-SR scores. Incremental cost-effectiveness ratios (ICERs) were calculated using bootstraps (5000 times) of seemingly unrelated regression equations and cost-effectiveness acceptability curves were constructed for the costs per QALY gained. RESULTS In total, 329 participants were included in the study of which 165 randomized to the CDMI group. At three months follow-up the responder rate was 13.9% in the CDMI group and 7.3% in the control group. Participants in the CDMI group gained 0.15 QALY at three months follow-up compared to baseline, whereas participants in the control group gained 0.03 QALY at three months follow-up. Average total costs per patient during 3 months follow-up were €2,094 for the CDMI group and €2,230 for the control group (excluding baseline costs). Bootstrapped SURE models resulted in a dominant ICER (i.e. less costs and a higher responder rate) for the CDMI group compared to the control group at three months follow-up. The same result was found for the costs per QALY gained. Various sensitivity analyses attested to the robustness of the findings of the main analysis. CONCLUSIONS This study demonstrated that brief and low-threshold web-based unguided self-help CDMIs have the potential to be a cost-effective addition to usual care for adults with mild-to-moderate depressive symptoms. The CDMIs were shown to improve health status while at the same time reduced healthcare costs of participants and hence dominates the care as usual control condition. As intervention costs are relatively low, and Internet is nowadays readily available in the Western world, we believe the CDMIs can be easily implemented on a large scale. CLINICALTRIAL Netherlands Trial Register (NTR): NTR4612; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4612 (Archived by WebCite at http://www.webcitation.org/6n4PVYddM)