Daily symptom variability in patients with stable COPD in Brazil

There are no studies reporting how respiratory symptoms vary throughout the 24-hour day in COPD patients in Brazil. To analyse 24-hour day variation of respiratory symptoms in stable COPD patients. Observational cross-sectional multicentric study in 8 centres in Brazil. Symptoms in the morning, at night and during the day were assessed the same as the Latin American Study of 24-hour Symptoms in Chronic Obstructive Pulmonary Disease (Miravitlles, M. et al. Respir Med 2018;134:62-69). 593 COPD patients on regular treatment were included. 52.1% male, mean age 67.7 years, mean FEV1 49.4%, 15.5% active smokers and 17.2% comorbid asthma. 183 patients (30.8%) classified as severe symptoms in the daytime reported reduced level of physical activity (p=0.002), higher airflow limitation (p<0.001), higher dyspnea (mMRC), worse CAT (p<0.001), and more hospital exacerbations (p=0,043). The most frequent symptoms were dyspnea (45.2% in the morning, 33.1% at night), cough (37.5% in the morning, 33.3% at night) and wheezing (24.4% in the morning, 27% at night). There was a strong correlation between the total score of daytime COPD symptoms questionnaire (E-RS) and severity of morning symptoms or night-time symptoms (r =0.65 and r =0.60, both p<0.001), and CAT score (r =0.62; p <0.001). There was a weak correlation with FEV1 (r = -0.21; p