Changes in characteristics of gastroenterology center inpatients in Japan because of rapidly aging society

Background and Aim Rapidly aging societies have become a major issue worldwide including Japan. This study aimed to elucidate relative changes in the characteristics of inpatients in Japan related to this issue. Methods A total of 23 835 Japanese inpatients treated from 2010 to 2021 were enrolled (2010–2013, period I; 2014–2017, period II; 2018–2021, period III). Changes in clinical features were retrospectively analyzed based on ICD‐10 diagnosis data. Results The percentage of patients aged over 75 years increased over time (period I, 38.0%; II, 39.5%, III, 41.4%). Emergency admissions comprised 27.5% of all in period I, which increased to 43.2% in period II and again to 44.5% in period III ( P < 0.001). In period I, gastrointestinal disease, liver disease, pancreatic‐biliary disease, and other disease types were noted in 47.4%, 29.5%, 19.2%, and 3.9%, respectively, while those values were 44.0%, 18.0%, 33.9%, and 4.1%, respectively, in period III ( P < 0.001). The frequency of liver disease decreased by approximately 0.6‐fold from periods I to III, while that of biliary‐pancreatic disease increased by approximately 1.8‐fold during that time. Both percentage and actual numbers of patients with biliary‐pancreatic disease increased during the examined periods. Analysis of changes in the proportion of organs affected by malignancy during periods I, II, and III showed a marked increase in cases of biliary‐pancreatic malignancy (11.6%, 19.5%, 26.6%, respectively) ( P < 0.001). Conclusion In association with the rapidly aging Japanese society, there has been an increasing frequency of biliary‐pancreatic disease cases requiring hospitalization for treatment in the west Japan region of Shikoku.