Age and etiological distributions of acquired PRCA in the Ptosh cohort. A total of 1055 patients with PRCA were identified in Ptosh. (A) A violin plot showing the age distribution of the patients. A total of 76% of them were >60 years old. (B) Distributions of the age of the patients with PRCA were depicted by sex, and we did not find a significant difference in age distributions (P = .3). (C) The pie chart shows an etiological distribution of PRCA in the present study. Among the 1055 patients with acquired PRCA, 69.0% had idiopathic PRCA. Other underlying causes included thymoma (9.4%), LGLL (2.5%), CLL (0.6%), and others (14.3%). (D) Age distributions in the 3 major subtypes of acquired PRCA were depicted in a violin plot, and a statistical difference was recognized between idiopathic and thymoma-associated PRCA, with median ages of 75 (range, 20-99) years old and 67 (range, 33-90) years old, respectively (P = .0006). A bimodal age distribution was observed in those with LGLL-associated PRCA. (E) The age distributions were not different between genders in respective subtypes of PRCA. The bimodal distribution in those with LGLL-associated PRCA was preserved in each gender group.