Difference in prevalence of metabolic syndrome between Japanese outpatients and inpatients with schizophrenia: A nationwide survey

Abstract

Patients with schizophrenia have a higher risk of metabolic syndrome (MetS). MetS prevalence varies with ethnicity. Although environmental factors, such as lack of physical activity and unbalanced diet, can lead to MetS, these may differ between outpatients and inpatients with schizophrenia. The Japanese mental health care system differs from that in other countries. However, few studies have investigated the prevalence of MetS in Japanese patients with schizophrenia. Therefore, we conducted a nationwide survey to clarify the prevalence of MetS in Japanese outpatients and inpatients with schizophrenia. We investigated the risk of MetS by questionnaire in 520 facilities for outpatients and 247 facilities for inpatients. There were 7655 outpatients and 15,461 inpatients with schizophrenia. MetS prevalence was based on the National Cholesterol Education Program Adult Treatment Panel III (ATP III-A) and the Japan Society for the Study of Obesity (JASSO). The overall MetS prevalence in outpatients using the ATP III-A definition was 34.2%, with 37.8% in men and 29.4% in women, compared with 13.0% in inpatients, with 12.3% in men and 13.9% in women. MetS prevalence in outpatients was approximately 2- to 3-fold higher than in inpatients. In conclusion, MetS prevalence in Japanese outpatients was approximately 3-fold higher than in inpatients. Therefore, we should pay more attention to the risk of physical disease in Japanese patients with schizophrenia, considering the difference in health characteristics between outpatients and inpatients.

Keywords: Hospitalisation; Japanese mental health care system; Metabolic syndrome; Prevalence; The Japan Society for the Study of Obesity (JASSO) definition; The adapted adult treatment panel III (ATP III-A) criteria.