Estimating Prevalence and Healthcare Utilization for Treatment-Resistant Depression in Japan: A Retrospective Claims Database Study

BACKGROUND Major depressive disorders (MDDs) including treatment-resistant depression (TRD) are common disabling conditions, but data on their epidemiology in Japan are limited. This study investigated the incidence, epidemiology, and direct medical costs of TRD and pharmaceutically-treated depression (PTD) in Japan to increase our health economic understanding of this phenotype of MDD. METHODS A retrospective cohort study from a private health insurance claims database estimated the 1-year incidence of PTD and TRD and described the health services used and direct medical costs associated with these conditions. RESULTS In the year from 1 April 2012 through 31 March 2013, we identified 1143 incident PTD cases among 98,552 eligible subjects, i.e. 11.59 cases/1000 patient-years. Of the PTD patients, 51.4% were women. Within the 1-year observation interval 137 patients failed more than two antidepressive treatment approaches and thus developed TRD. Though co-morbid conditions and age were similar among PTD and TRD patients, medical costs per patient (patient-year) during their treatment intervals were 1.01 million JPY (0. 540 million JPY) in the TRD population and 0.643 JPY million JPY (0.645 million JPY) in the PTD population who did not convert into TRD. CONCLUSIONS This study describes the PTD and TRD patient populations in a large claims database in Japan and highlights an unmet medical need for the treatment of TRD to provide better preventative measures and interventions for the treatment of depression.