Cost Utility Analysis of Internet-Based Cognitive Behavioral Therapy for Major Depressive Disorder: Randomized Controlled Trial
Authors: Zhou Wenjing , Chen Yan , Wu Herui , Zhao Hao , Li Yanzhi , Shi Guangduoji , Wang Wanxin , Liu Yifeng , Liao Yuhua , Zhang Huimin , Gao Caihong , Hao Jiejing , Le Gia Han , McIntyre Roger S , Han Xue , Lu Ciyong 
Published: December 2024

Background
Unguided internet-based cognitive behavioral therapy (ICBT) has been proven effective for major depressive disorder (MDD). However, few studies have examined its cost-effectiveness in low-resource countries and under nonspecialist routine care.

Objective
This study aimed to evaluate the short- and long-term cost utility of unguided ICBT compared to a waitlist control for persons with MDD from the perspectives of society and the health care system.

Methods
This analysis was implemented alongside an 8-week 2-arm randomized controlled trial with a 12-month follow-up period conducted in Shenzhen, China. Outcomes including cost and health utility were collected at the pretreatment and posttreatment time points and 3, 6, and 12 months after the intervention. Direct medical costs and indirect costs were prospectively collected using the hospital information system and the Sheehan Disability Scale. Health outcomes were measured using the Chinese version of the Short-Form Six-Dimension health index. The primary outcome was incremental cost utility ratio (ICUR) expressed as the difference in costs between 2 therapies by the difference in quality-adjusted life years (QALYs). The seemingly unrelated regression model and the bootstrap method were performed to estimate adjusted ICURs. Cost-effectiveness planes and cost-effectiveness acceptability curves were used to demonstrate uncertainty. A series of scenario analyses were conducted to verify the robustness of base-case results.

Results
In total, 244 participants with MDD were randomly allocated to the ICBT (n=122, 50%) or waitlist control (n=122, 50%) groups. At the pretreatment time point, no statistically significant difference was observed in direct medical cost (P=.41), indirect cost (P=.10), or health utility (P=.11) between the 2 groups. In the base-case analysis, the ICBT group reported higher direct medical costs and better quality of life but lower total costs at the posttreatment time point. The adjusted ICURs at the posttreatment time point were CN ¥–194,720.38 (US $–26,551.50; 95% CI CN ¥–198,766.78 to CN ¥–190,673.98 [US $–27,103.20 to US $–25,999.70]) and CN ¥49,700.33 (US $6776.99; 95% CI CN ¥46,626.34-CN ¥52,774.31 [US $6357.83-$7196.15]) per QALY from the societal and health care system perspectives, respectively, with a probability of unguided ICBT being cost-effective of 75.93% and 54.4%, respectively, if the willingness to pay was set at 1 time the per-capita gross domestic product. In the scenario analyses, the probabilities increased to 76.85% and 77.61%, respectively, indicating the potential of ICBT to be cost-effective over the long term.

Conclusions
Unguided ICBT is a cost-effective treatment for MDD. This intervention not only helps patients with MDD improve clinically but also generates societal savings. These findings provide health economic evidence for a potential scalable MDD treatment method in low- and middle-income countries.

Trial Registration
Chinese Clinical Trial Registry (ChiCTR) ChiCTR2100046425; https://tinyurl.com/bdcrj4zv