{
  "abstract": "Objectives Due to the big disease burden of undiagnosed chronic obstructive pulmonary disease (COPD), we aimed to investigate the differences in the characteristics and risk factors of patients with undiagnosed COPD in China.Methods We used data from the ‘Happy Breathing’ Programme through April 2023. Current study is a cohort design. Participants were divided into high risk, undiagnosed and diagnosed COPD. Univariate logistic regression, lasso regression, decision tree, random forest and gradient boosting machine were used to screen the variables. Comparisons were conducted between undiagnosed and patients with diagnosed COPD.Results A total of 1603 high-risk, 4688 undiagnosed and 1634 patients with diagnosed COPD were identified. Patients with undiagnosed COPD had the lowest level of education, the poorest COPD-related knowledge and most biofuel users compared with high-risk populations and diagnosed patients (p<0.001). After multivariable logistic regression analysis, COPD-related knowledge score (OR=0.96, 95% CI 0.95 to 0.97), COPD Assessment Test Score (OR=1.01, 95% CI 1.00 to 1.02) and modified Medical Research Council Dyspnea Scale (OR=1.26, 95% CI 1.14 to 1.39) remained significant. Analysis of follow-up data showed that patients with undiagnosed COPD had lighter symptoms and experienced less acute exacerbations than diagnosed patients (p<0.001).Discussion Most patients with COPD remain undiagnosed until they feel dyspnoea or hospitalisation due to acute exacerbation. Undiagnosed COPD contributes significantly to the disease burden.Conclusion In China, patients with undiagnosed COPD were poorly educated, consumed more biofuels, smoked more and had limited COPD-related knowledge. Patients with undiagnosed COPD are also at risk of acute exacerbation.Trial registration number NCT04318912.",
  "authors": [
    {
      "affiliations": [
        "China-Japan Friendship School of Clinical Medicine, Capital Medical University, Beijing, China",
        "Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China"
      ],
      "name": "Xingyao Tang"
    },
    {
      "affiliations": [
        "General Office, China-Japan Friendship Hospital, Beijing, China"
      ],
      "name": "Jun Pan"
    },
    {
      "affiliations": [
        "Administration Office of Medical Reform and Development, China-Japan Friendship Hospital, Beijing, China"
      ],
      "name": "Fang Fang"
    },
    {
      "affiliations": [
        "Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China"
      ],
      "name": "Yong Li"
    },
    {
      "affiliations": [
        "Data and Project Management Unit, Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, China"
      ],
      "name": "JiePing Lei"
    },
    {
      "affiliations": [
        "Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China"
      ],
      "name": "Hongtao Niu"
    },
    {
      "affiliations": [
        "Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China"
      ],
      "name": "Wei Li"
    },
    {
      "affiliations": [
        "Data and Project Management Unit, Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, China"
      ],
      "name": "Fen Dong"
    },
    {
      "affiliations": [
        "Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China",
        "China-Japan Friendship School of Clinical Medicine, Peking University, Beijing, China"
      ],
      "name": "Zhoude Zheng"
    },
    {
      "affiliations": [
        "Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China",
        "China-Japan Friendship School of Clinical Medicine, Peking University, Beijing, China"
      ],
      "name": "Yaodie Peng"
    },
    {
      "affiliations": [
        "Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China"
      ],
      "name": "Ting Yang"
    },
    {
      "affiliations": [
        "Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China",
        "School of Population Medicine and Public Health, Peking Union Medical College Hospital, Beijing, China"
      ],
      "name": "Chen Wang"
    },
    {
      "affiliations": [
        "General Office, China-Japan Friendship Hospital, Beijing, China"
      ],
      "name": "Cunbo Jia"
    },
    {
      "affiliations": [
        "Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China"
      ],
      "name": "Ke Huang"
    }
  ],
  "title": "Characteristics and risk factors of patients with undiagnosed COPD in China: results of a nationwide study from the ‘Happy Breathing’ Programme with mixed methods evaluation",
  "uid": "b20fa1d2-02da-5b65-966c-cece3062b142"
}