A longitudinal study evaluating the relationship between exacerbations and directly measured physical activity in outpatient COPD patients (original) (raw)

2012, European Respiratory Journal

Body: This longitudinal study was designed to evaluate changes in physical activity during COPD exacerbations. IRB approval was obtained and all patients provided consent before participation. Those with a clinical and spirometric diagnosis of COPD, a history of 2 or more exacerbations in the past year, and no exacerbations in the past 4 weeks were recruited. Physical activity was measured using an actigraph device worn continuously (24 hrs/day) on the wrist. The number of minutes per 24-hour day at moderate, vigorous, and very vigorous activity levels were recorded as outcomes. Exacerbations were defined by changes in the 14-item, Exacerbations of Chronic Pulmonary Disease Tool (EXACT), which was filled out daily. Patients remained in the study for 6 months or until 4 weeks after the onset of an exacerbation. The study, which commenced in December, 2011, is designed to be event-driven until 20 exacerbations are recorded. To date, 12 patients have been enrolled: 7 males; mean age 61 years, mean FEV1 53%. Seven had EXACT-defined COPD exacerbations (mean change = 15 units) over 1200+ total patient-days of observation. Exacerbation durations ranged from 1 to 11 days. Mean daily physical activity on exacerbation days tended to be lower than on non-exacerbation days: moderate activity, 70 ± 25 (SE) vs. 99 ± 12 minutes (p = 0.19); vigorous activity, 55 ± 12 vs. 74 ± 10 minutes (p = 0.01); and very vigorous activity, 6 ± 4 vs.11 ± 3 minutes (p = 0.07). In summary, this longitudinal study suggests that physical activity decreases during COPD exacerbations.