Impact of comorbidities on physical activity in COPD.

BACKGROUND AND OBJECTIVE: Both comorbidities and physical inactivity have been shown to impair quality of life and contribute to hospital admissions and mortality in chronic obstructive pulmonary disease (COPD) patients. We hypothesized that the comorbid status predicts the level of daily physical activity (PA) in COPD.

METHODS: In 228 patients with COPD (76% men; median (quartiles) age: 64 (59/69) years; percentage of predicted forced expiratory volume in 1 s (FEV1 % pred): 44 (31/63)), comorbidities were assessed by medical history, clinical interviews, examination and blood analysis. PA level (PAL) was measured by an activity monitor (SenseWear Pro, Bodymedia Inc., Pittsburgh, PA, USA). The association between PAL and comorbidities was investigated by univariate and multivariate regression analysis.

RESULTS: Seventy-nine percent of the COPD patients had at least one additional chronic comorbidity, 56% had two or more comorbidities and 35% had three or more comorbidities. In univariate analysis body mass index, the number of pack years and having at least one additional comorbidity was negatively associated with PAL while there was a positive nonlinear association between FEV1 and PAL. The presence of at least one additional comorbidity was independently associated with PAL irrespective of airflow limitation.

CONCLUSIONS: In this cohort, almost 80% of COPD patients had at least one additional chronic comorbidity. The level of daily PA seems to be significantly impaired by the presence of comorbidities irrespective of the type of comorbidity and independent of the degree of airflow limitation.

CLINICAL TRIAL REGISTRATION: NCT01527773 at https://www.clinicalTrials.gov.