Usual Care
Health-care providers and general practitioners provided subjects in the control group with usual care according to the subjects’ needs. Every 2 months, the caregivers were asked to determine each subject’s condition by telephone or at a face-to-face follow-up visit, record the subject’s status at the health-care stations, and then report this information to our study group. In case of deterioration, subjects were treated with drugs in accordance with the GOLD guidelines or referred to a respiratory specialist. The content and frequency of usual care services were not standardized.