Cohen MD (VA, NYHHCS, Brooklyn campus), Cutaia M
(VA, NYHHCS, Brooklyn campus)
Motion sensors (accelerometers) can precisely measure physical activity while patients are living freely in their home environment. Studies using accelerometers have demonstrated that patients with chronic obstructive pulmonary disease (COPD) have lower activity levels than their healthier counterparts. The level of daily activity in patients on long-term oxygen therapy (LTOT) is likely even more compromised, but this has never been described in detail. It is the purpose of this study to determine whether a new method to measure daily activity can define differences in physical activity between COPD patients on LTOT and patients with severe COPD not on LTOT.
44 patients with severe COPD (FEV1% < 50) underwent an ambulatory activity study wearing two accelerometers. 22 patients met standard criteria for LTOT and 22 patients did not. From the accelerometers, four distinct categories of daily activity were identified: walking, slow/intermittent walking, activity while not walking and resting. Activity profiles were compared between groups.
The COPD cohort group on LTOT spent significantly less time engaged in activities that require acceleration (walking and slow/intermittent walking) and walked slower than the non-LTOT patients; in addition, LTOT patients spent more time active while not walking than non-LTOT patients (all p-values < .05). There was no difference between groups in time patients spent resting or in spirometry (all p-value > .05).
The detailed daily profile reveals that COPD patients on LTOT are less physically activity than non-LTOT patients with severe disease.
This is one of the first studies to describe in detail the daily activity patterns in COPD patients on LTOT. Ambulatory techniques provide methods to gather quantitative clinical data in the most relevant settings for patients. These techniques can provide methods to measure the value of interventions aimed at improving the level of everyday physical activity in COPD. Small improvements in physical activity may have a meaningful impact on this very sedentary population.