Cost-utility and cost-effectiveness analyses of an internet-based self-management program for bipolar disorder: Randomised controlled trial (Preprint)

Abstract

Internet delivered psychosocial interventions can overcome barriers with face-to-face psychosocial care. Limited evidence supports the cost-effectiveness of online psychosocial therapies for people with bipolar disorders.

To conduct a within trial economic evaluation of an online intervention for people with bipolar disorder, Moodswings 2.0 from an Australian health sector perspective.

Moodswings comprised an economic evaluation alongside an international, parallel, individually-stratified randomised controlled trial comparing an online discussion forum (control; Group 1) to a discussion forum plus online psychoeducation (Group 2) and to a discussion forum plus psychoeducation and cognitive behavioural tools (Group 3). The trial enrolled adults (21 to 65 years) with a diagnosis of bipolar disorder assessed by phone using the Structured Clinical Interview for DSM-5. Health sector costs included intervention delivery and additional health care resources utilised by participants over the 12-month trial follow-up. Outcomes included depression symptoms measured by the Montgomery-Asberg Depression Rating Scale (MADRS) (the trial primary outcome), and quality adjusted life years (QALYs) calculated using SF-6D derived from the SF-12. Average incremental cost-effectiveness (cost/MADRS) and cost-utility (cost/QALY) ratios were calculated using estimated mean differences between intervention and control groups from linear mixed-effects models in the base case. Sensitivity analyses evaluated methods of managing missing data and varying key cost parameters.

A total of 304 participants were randomised. Average health sector cost was lowest for Group 2 ($9,705) compared to the control group ($15,175) and Group 3 ($15,518), but none were statistically significantly different. The average QALYs were not significantly different between groups (Group 1 0.627; Group 2 0.618; Group 3 0.622). MADRS scores were previously shown to differ significantly between Group 2 and the control group at all follow-up timepoints (p<0.05). Group 2 was dominant (lower costs and greater effects) compared to the control group for average incremental cost per point decrease in MADRS score over 12 months (95% CI: Dominated to $331). Average cost per point change in MADRS score for Group 3 versus control group was $156 (95% CI: Dominant to $22,585). Group 2 was dominant over the control group based on lower average health sector cost and average QALY benefit of 0.01 (95% CI: $43,000 to Dominant). There was an 86% probability that the psychoeducation modules would be cost-effective at the $50,000/QALY threshold. Group 3 compared to the control group had an average ICER of $173,315/QALY (95% CI: Dominated to $19,978) with a 47% probability of being cost-effective at the $50,000/QALY threshold.

Online psychoeducation through the Moodswings 2.0 platform has the potential to be a cost-effective intervention for people with bipolar disorder. This component should be implemented with continuing evaluation. Additional research is required to understand the lack of response to the addition of online CBT tools.

This study was registered with ClinicalTrials.gov NCT02106078 and NCT02118623. Ethical approval for the study was obtained by the Institutional Review Board at Stanford University (Stanford, CA, USA), the Barwon Health and Deakin University Human Research Ethics Committees (Geelong, Australia).