Smartphone app aims to predict and prevent COPD attacks using weather data

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Hospital inclusion criteria: 1. Tertiary hospitals; 2. Hospitals with respiratory wards that admit patients with COPD; 3. Hospitals with a well-established electronic health record system and follow-up capability; 4. Hospitals able to assign a study coordinator. Patient inclusion criteria: 1. Age \>=40 years and \<=80 years, with no restriction on sex; 2. Patients with stable chronic obstructive pulmonary disease; 3. At least 1 severe acute exacerbation requiring hospitalization, or at least 2 moderate acute exacerbations requiring outpatient or emergency care, within the previous year; 4. Local permanent residents with a duration of residence \>=6 months; 5. Patients who voluntarily agree to participate, are expected to have good adherence, are able to sign informed consent; 6. Patients who own a smartphone or other smart device. Hospital exclusion criteria: 1. Primary hospitals or private hospitals; 2. Hospitals unable to cooperate with the study protocol. Patient exclusion criteria: 1. Patients with asthma; 2. Women who are known to be pregnant or breastfeeding, or who have a positive pregnancy test before cluster randomization; 3. Patients with other diseases that may affect participation in the trial, such as refractory hypertension or severe aphasia; 4. Patients currently receiving psychiatric or psychological treatment that may contaminate study results; 5. Expected survival time \<1 year, such as in those with malignant tumors or severe cardiopulmonary disease; 6. Participation in other interventional clinical studies that may affect outcome assessment; 7. Any other circumstances in which the investigator considers the patient unsuitable for participation in this study or at significant risk, such as cognitive impairment preventing understanding of and/or compliance with study procedures and/or follow-up.