Associations of comorbid heart disease and depression/anxiety with multidimensional breathlessness in COPD – A cross-sectional study

BACKGROUND: Comorbid conditions and breathlessness are associated with poor outcomes in chronic obstructive pulmonary disease (COPD). We evaluated the associations of comorbid heart disease and depression/anxiety with breathlessness in daily life among people with COPD. METHODS: Cross-sectional analysis from the PRAXIS cohort in central Sweden. Data on patient characteristics and the modified Medical Research Council (mMRC) and Dyspnea-12 breathlessness instruments (D-12) were obtained from questionnaires in 2022. Lung function data were collected from record review. Outcome variables were clinically significant breathlessness defined as mMRC≥2 and D-12 total (>2.7), physical (>1.4) and affective (>1.2) scores above published minimal clinical important differences. Associations of heart disease and depression/anxiety with each outcome were analyzed using multivariable Poisson regression adjusted for relevant confounders. RESULTS: In 522 included patients, mMRC ≥2 was present in 59 % and increased D-12 total, physical and affective domain scores in 69 %, 74 %, and 50 %, respectively. Heart disease was independently associated with mMRC (relative risk ratio [95 % confidence interval] 1.34 [1.17-1.53]), D12 physical domain (1.12[1.02-1.24]) and D-12 affective domain (1.20[1.02-1.42]). Depression/anxiety was independently associated with increased D-12 affective domain (1.25[1.04-1.49]). In addition, previous exacerbations and GOLD stage 3-4 were associated with mMRC and D-12, respectively. CONCLUSION: In COPD, comorbid heart disease is associated with both activity-related breathlessness and with physical and affective domains of breathlessness while depression/anxiety is associated with the affective domain of breathlessness. As the influence of different dimensions of breathlessness may differ according to comorbidity the D-12 instrument adds more information when assessing breathlessness in patients with COPD.