Impact of initial treatment outcome on long-term costs of depression: a 3-year nationwide follow-up study in Taiwan

Background. The impact of initial treatment outcome on long-term healthcare costs in depression remains to be determined. We aimed to identify demographic and clinical characteristics associated with initial treatment outcomes and to test whether and how these outcomes influence total healthcare costs over the subsequent 3 years. Method. In this secondary analysis of a large healthcare database, a national cohort of adult patients (n=126471) who received antidepressant treatment for depression was identified and factors associated with initial outcomes were examined. Potential predictors of total healthcare costs in the subsequent years were assessed using generalized linear modeling, with a particular focus on initial outcome status after antidepressant treatment and co-morbidities. Results. Depression type and co-morbid painful physical symptoms (PPS) or mental illnesses were found to be associated with initial outcome status. Having sustained treatment-free status after initial treatment was shown to be associated with a 22-33% reduction in total healthcare costs in the second and third years (compared to those with late recontacts). Although the presence of co-morbid PPS was associated with higher healthcare costs, having certain co-morbid anxiety disorders was associated with lower costs over the 3 years. Conclusions. Initial outcome status after antidepressant treatment has a sustained impact on individuals' total healthcare costs over the following 3 years. Future efforts to improve initial treatment outcome of depression are warranted.