Aims:  The severity of chronic obstructive pulmonary disease (COPD) is associated to patients’ health-related quality of life (HRQL). Physical impairment increasingly affects daily activities creating economic, social and personal burden for patients and their families. This burden should be considered in the management of COPD patients; therefore, we intended to assess the impact of the disease severity on physical disability and daily activities.

Methods:  Two epidemiological observational cross-sectional descriptive studies were carried out in 1596 patients with moderate COPD and 2012 patients with severe or very severe COPD in the routine clinical practice. Demographic and basic clinical-epidemiological data were collected and patients completed questionnaires to assess their physical disability because of COPD [Medical Research Council (MRC)], COPD repercussion on daily activities [London Chest Activity of Daily Living (LCADL)], job, economy and family habits and their health status [EQ-5D visual analogue scale (VAS)].

Results:  In all, 37% of severe/very severe COPD patients and 10% of moderate (p < 0.0001) had MRC grades 4 and 5. Mean global LCADL was significantly higher in severe/very severe than in moderate patients [29.6 (CI 95%: 28.91–30.25) vs. 21.4 (CI 95%: 20.8–21.9); p < 0.0001]. COPD job impact and economic and family habits repercussions were significantly higher and health status significantly worse in severe/very severe cases than in patients with moderate COPD.

Conclusions:  COPD severity is highly associated with physical disability by MRC grading, with functionality on daily activities and with impairment of other social and clinical activities. Moderate COPD patients show already a significant degree of impairment in all these parameters.