Data are presented as mean ± standard deviation, median (interquartile range), or numbers (percentages). BMI: body mass index; CHA: cold hemagglutination; CI: confidence interval; CRP : C-reactive protein; DPB: diffuse panbronchiolitis; ESR: erythrocyte sedimentation rate; FEF: forced expiratory flow; FEV1: forced expiratory volume in 1 second; FVC: forced vital capacity; OR: odds ration; PaCO2: arterial pressure of carbon dioxide; PaO2: arterial pressure of oxygen; pH: potential of hydrogen; RV: residual volume; WBC: white blood cell. ※Disease duration was defined as the time from the first DPB symptoms onset to the first visit to hospital. ▲Comparison of DPB subjects with and without bronchiectasis. ■A positive CHA test was defined as a value greater than 1 : 64.