The association between objectively measured physical activity and morning symptoms in COPD

The morning is the most bothersome period for COPD patients. Morning symptom severities in different Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages are not well studied. Furthermore, factors that are associated with morning symptoms, especially the associations with objectively measured physical activity, are also not well described.

The aim of this cross-sectional observational study was to assess morning symptom severity in GOLD A, B, C and D patients, according to the definitions of the GOLD 2015 statement. Morning symptoms were assessed with the PRO-Morning COPD Symptoms Questionnaire. Differences in morning symptom severity between different COPD stages were assessed with a one-way analysis of variance followed by post hoc analyses. The association between dyspnea severity (assessed with the modified Medical Research Council scale), health status, airflow limitation, lung hyperinflation, anxiety and depression, inflammatory parameters, exacerbations, objectively measured physical activity parameters retrieved from accelerometry and morning symptom severity was evaluated using linear regression analysis.

Eighty patients were included (aged 65.6±8.7 years, forced expiratory volume in 1 second [FEV₁] % predicted 55.1±16.9). Mean (±SD) morning symptom score was 19.7 (±11.7). Morning symptom severity was significantly different between COPD stages: mean (±SD) score in GOLD A was 9.7 (±7.2), in GOLD B 19.8 (±10.7), in GOLD C 8.6 (±9.3) and in GOLD D 23.8 (±11.2) (p<0.001). Lower health status, more symptoms, increased anxiety and depression, less physical activity (all p<0.001) and lower FEV₁ (p=0.03) were associated with an increased morning symptom severity.

Patients with overall more symptomatic COPD have significant higher morning symptom scores. Morning symptom severity was associated with important clinical outcomes: lower health status, more symptoms, increased anxiety and depression, fewer steps a day, less time in moderate and vigorous physical activity with bouts of at least 10 minutes and lower FEV₁. The data suggest that morning symptoms should be carefully assessed in addition to assessment by general COPD-specific questionnaires, especially in those with more symptomatic COPD. More research is needed on potential therapies to improve morning symptoms; this study shows potential targets for intervention.