Data collection
depression, comorbidity, breast cancer
BREAST CANCER
The patients’ clinical information was collected from the electronic medical records of the hospital. Clinical data included age at diagnosis, marital status, education, occupation, comorbidity, past episodes of depression, and breast cancer treatments. We also collected 2 types of out-of-hospital data: daily step counts from the WalkON app and app-based self-reported distress questionnaire. During the app registration process, patients received anonymous IDs from researchers, and their information was entered into an external server. As for the self-reported distress questionnaire, all patients in the intervention group and the control group were instructed to fill out a questionnaire on the Distress Thermometer (DT) on a weekly basis. DT (see Figure a in 