Disease knowledge level is a noteworthy risk factor of anxiety and depression in patients with chronic obstructive pulmonary disease: a cross-sectional study

BACKGROUND: Risk factors of anxiety and depression symptoms in patients with chronic obstructive pulmonary disease (COPD) have been widely researched, but most of them cannot be addressed clinically. The aim of this study was to investigate whether COPD knowledge level is a risk factor of anxiety and/or depression in COPD patients in addition to functional capacity and quality of life, and to determine the key topics of COPD knowledge. METHODS: A total of 364 COPD patients from four centers were recruited into this cross-sectional survey. Subjects’ general medical information, assessments of lung function, dyspnea, quality of life, and exercise capacity, and responses to the Hospital Anxiety and Depression Scale (HAD) and the Bristol COPD Knowledge Questionnaire (BCKQ) were collected. Partial correlation analysis was performed, and a multivariable model testing risk factors of anxiety and depression as well as a multivariable model of 13 topics of knowledge derived from BCKQ were constructed. RESULTS: Subjects with anxiety or depression were more likely to have less COPD knowledge. Partial correlation analysis revealed that HAD score was negatively correlated with BCKQ score (rho = −0.153, P = 0.004). BCKQ score was significant in the multivariable model that tested risk factors of anxiety and depression (P = 0.001, OR = 0.944). Topics of epidemiology (P < 0.001, OR = 0.653) and infections (P = 0.006, OR = 0.721) were significant in the multivariable model evaluating 13 topics. CONCLUSIONS: The level of patients’ disease knowledge is a significant risk factor of anxiety and depression in COPD patients. Epidemiology and infections are key topics of COPD knowledge to target in the Chinese population. TRIAL REGISTRATION: ChiCTR-OCS-12002518