Study participants
The present study analyzed data from a nationwide claims-based database that included information on 296,129 people enrolled with a health insurance provider for company employees and their dependents in Japan [9]. Details of the claims data and classifications were described elsewhere [8.9.10]. Patients aged 19–72 years who were followed for at least 3 years from 1 April 2008 to 31 March 2013 were included in this analysis and continued to be followed up to 31 September 2016. We examined data on 296,129 individuals in the present study. We then excluded 37,255 individuals due to missing data and panic data. Finally, this study included 258,874 individuals who were outpatients at the time of baseline measurements (241,628 DM and 17,246 non-DM).