Background: Cough and sputum production are frequent in chronic obstructive pulmonary disease (COPD). The objective of this study was to examine the relationship between cough and sputum production and health-related quality of life in COPD.
Methods: A cross-sectional study was conducted in the French Initiatives COPD cohort and assessed cough and sputum production within the past 7 days using the cough and sputum assessment questionnaire (CASA-Q), health-related quality of life, spirometry, smoking status, dyspnea, exacerbations, anxiety and depression, and comorbidities.
Results: One hundred and seventy-eight stable COPD patients were included (age, 62 [56-69] years, 128 male, forced expiratory volume in 1 second [FEV1]: 57 [37-72] % predicted) (median [Q1-Q3]). In univariate analyses, health-related quality of life (Saint George's respiratory questionnaire total score) was associated with each CASA-Q domain and with chronic bronchitis, exacerbations, dyspnea, FEV1, depression, and anxiety. All four domains introduced separately were independently associated with health-related quality of life. When introduced together in multivariate analyses, only the cough impact domain remained independently associated with health-related quality of life (R2=0.60). With chronic bronchitis (standard definition) instead of the CASA-Q, the R2 was lower (R2=0.54).
Conclusion: This study provides evidence that current cough in the previous 7 days is an important determinant of health-related quality of life impairment in stable COPD patients.
Keywords: dyspnea; multivariate analysis; questionnaires; respiratory; signs and symptoms; sputum.