The underrated prevalence of depression in Japanese patients with rheumatoid arthritis - evidence from a Nationwide survey in Japan

BACKGROUND: To determine the prevalence of depression among Japanese people with rheumatoid arthritis (RA) and explore the relationships between depression and an array of variables. METHODS: Nation-wide, cross-sectional online survey (n = 500) of people with RA including the Patient Health Questionnaire (PHQ-9) to measure the presence and severity of depressive symptoms were performed. RESULTS: While only 5% of the population studied had been officially diagnosed with depression, 35% had PHQ-9 scores indicating depression was present. People with RA are more likely to experience depression if they are younger, have greater functional impairment, or whose treatment regimen includes pain medications not biologic agents. CONCLUSIONS: It is a potential risk of under-diagnosis and under-reporting of depression in Japanese people with RA. People with RA are more likely to experience depression if they are younger, have greater functional impairment, or whose treatment regimen includes pain medications without biologic drugs. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s41927-017-0003-6) contains supplementary material, which is available to authorized users.