Assessing the Cost-Effectiveness and Exploring the Implementation of Interventions for Major Depression in Thailand

Abstract This thesis aims to provide policy makers in Thailand with an evidence base for prioritizing interventions for major depression. The first objective was to determine adherence to antidepressant drugs for the treatment of major depression. The second objective was to identify an optimal set of treatments for major depression in Thailand based on cost-effectiveness analyses (CEA). The final objective was to make recommendations regarding the implementation of the most cost-effective interventions to address major depression in the context of Thailand’s health services. A mixed method research design was used combining quantitative methods to determine adherence and cost-effectiveness with qualitative methods to explore issues around the implementation of cognitive behavioral therapy (CBT), a psychotherapeutic intervention that was found to be cost-effective, if the effectiveness reported in the international literature can be replicated in Thailand. Adherence was only 41% in the cohort of patients attending health services at least twice. If we assume that all patients who attended only once were non-adherent, adherence would have been as low as 23%. A large proportion of cases received more than one drug per visit or was switched from one drug to another (39%). This level of adherence to antidepressant therapy for the treatment of major depression in Thailand is rather low compared to findings from elsewhere. Generic fluoxetine, a selective serotonin re-uptake inhibitor (SSRI), CBT and a screening program in primary care followed by the same treatments were selected for cost-effectiveness analysis. Generic fluoxetine is the cheapest drug option in Thailand and evidence shows no difference in effectiveness between different classes of antidepressant drugs. CBT is the psychotherapy treatment option with the largest evidence base of effectiveness. The cost-effectiveness ratios for treating depression in Thailand with generic fluoxetine or CBT fall below the threshold of 1 times gross domestic product (GDP) per capita (110,000 Baht in Thailand in 2005), the recommended cut-off for an intervention to be considered “very cost-effective”. The uncertainty intervals overlap, meaning that CBT and generic fluoxetine are equally cost-effective treatment options for the treatment of major depression in Thailand. Similarly favorable results were obtained for the cost-effectiveness of using either treatment option during episodes only or as a maintenance treatment variant over a five-year period. The cost-effectiveness ratio s for screening followed by CBT treatment or drug treatment also fell below 1 times GDP per capita. The shortage of mental health personnel, especially psychiatrists and psychologists, who would be expected to deliver treatments for patients with major depression in Thailand, means that policy makers would need to consider the cost of training and expanding the work force. It is estimated that currently less than 5% of people with depression are being treated. While we have identified that a screening program is a cost-effective option to increase case-detection for depression in primary care, its implementation would further increase the workload of already stretched primary care and mental health services in Thailand. Concerned that the favorable results for CBT are largely based on overseas evidence of effectiveness, we conducted in-depth interviews and a focus group discussion with psychiatrists, psychologists, psychiatric nurses, and policy makers in a major psychiatric hospital in central Thailand. Respondents unanimously agreed that there is a need to add more psychological interventions to the current approach that is dominated by a biomedical treatment for depression. Most agreed that with some adjustment for cultural appropriateness, CBT could be acceptable and effective. However, the limited time available to psychiatric health workers and the lack of trained personnel were identified as the main barriers to implementation. There are a lot of strengths worth noting in this thesis. Firstly, where we could, we endeavored to use data from real life settings that are representative of Thailand rather than relying on results from elsewhere. A second strength is that we used a micro-simulation model that helped to capture the heterogeneity in length and frequency of depressive episodes. Another strength is that the efficacy data of antidepressant drugs used for the cost-effectiveness analyses were from a meta-analysis that took into consideration unpublished data from pharmaceutical companies, thus avoiding the publication bias which affects meta-analyses of published trials. However, there are limitations in this research that should be addressed. The first limitation is that there was no information on the effectiveness of the treatment options for major depression in Thailand. We had to rely on information from international meta-analyses. The effect size of these interventions from clinical trials may not directly translate into effectiveness in Thai routine health services, a particular concern for CBT which has not yet been introduced in Thailand apart from small-scale pilot projects. Secondly, the adherence study and the qualitative study were conducted in just one hospital. In addition, the respondent group of the qualitative study was small. For those reasons, these studies should be considered as a first step with further studies required to assess the generalisability of the findings. The last limitation, due to resource limitations of the project, is that we could not assess all possible interventions for the management of major depression in Thailand. For example, future analyses could be extended to include psycho-education, counseling, self-help interventions such as bibliotherapy (self-help books) and internet-based therapy for patients with depression in Thailand. Further qualitative research is also needed to explore the reasons for the low coverage and low adherence to antidepressant therapy in order to formulate interventions to improve the coverage of treatment for depression in Thailand. Concluding remarks: • Generic fluoxetine or CBT is an intervention to be considered “very cost-effective” for treating depression in Thailand. • There is a need to add more psychological interventions to the current treatment for depression, , CBT could be acceptable and effective with some adjustment for cultural appropriateness • However, the limited time available to psychiatric health workers and the lack of trained personnel were identified as the main barriers to implementation CBT in Thailand