Evaluating the impact of morning symptoms in COPD using the Capacity of Daily Living during the Morning (CDLM) questionnaire

Abstract

Purpose: The aim of this study was to evaluate the impact of morning symptoms in COPD using the Capacity of Daily Living during the Morning (CDLM) questionnaire and to determine the clinical variables that are related to CDLM scores. Methods: This was an observational, cross-sectional, and multicenter study conducted in stable COPD patients. CDLM scores ranged from 0 to 5 and were transformed into a qualitative variable according to tertile values to compare patient characteristics. A multivariate linear regression model was used to identify the clinical variables related to CDLM scores. Results: A total of 605 patients were included in the study; the mean age (SD) was 68 years (9.1) and mostly were male (80.8%). The mean post-bronchodilator FEV1% was 53.4% (19.2%), and the mean BODEx (body mass index, airway obstruction, dyspnea, exacerbation) score was 3.2 (2.0). The mean COPD assessment test (CAT) score was 16.6 (8.3), and the mean CDLM score was 4.2 (0.9). First tertile patients, that is, those with a higher impact in the morning, were older, had more respiratory symptoms, more dyspnea, a lower FEV1%, lower CAT and BODEx scores, and more exacerbations. We found a ceiling effect on the CDLM scores: 194 (32%) patients scored 5.00 and no patients scored 0. On multivariate analysis, higher CAT and BODEx scores, a lower FEV1%, and use of long-term oxygen therapy (LTOT) were all independently related to lower CDLM scores. Conclusion: Morning respiratory symptoms are associated with more severe airflow obstruction, lower CAT and BODEx scores, and LTOT. The ceiling effect of the CDLM questionnaire does not allow it to discriminate well between low and high impact of morning symptoms.