Clinical Course of Ulcerative Colitis Associated with an Age at Diagnosis: A Recent Japanese Database Survey

The onset age of ulcerative colitis has been increasing in several countries. Furthermore, the number of elderly patients with ulcerative colitis has been increasing in an aging society. We investigated the incidence of ulcerative colitis patients in Japan using a large-scale health insurance claims database to survey the ulcerative colitis incidence ratio and the clinical characteristics in late-onset ulcerative colitis patients. Newly diagnosed 2,791 ulcerative colitis between 2015 and 2018 was investigated. Medical treatment within 12 months of diagnosis was analyzed among 0-19, 20-39, 40-59 and 60-75 age groups. The mean age at diagnosis was 40.3 years (SD: 12.9), and the incidence ratio peaked in the 40's. Most of patients received 5-aminocylitic acid (91.7%), a subset of patients received prednisolone (20.1%), and a small number of patients took immunomodulator (6.8%), cytapheresis (3.3%), anti-TNFα therapy (4.3%), and colectomy (1.0%) within 12 months after diagnosis. All treatments except colectomy were most frequent in the 0-19 age group; however, colectomy was most frequent in 60-75 age group. The clinical course of ulcerative colitis that developed in adults did not differ significantly in terms of medical treatment within 12 months from the onset; meanwhile, the surgery rate was high in elderly patients. It is necessary to pay close attention to future trends regarding the aging of the onset age and the treatment, especially for late-onset ulcerative colitis patients.