The broad range of interventions to increase physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD) has not been systematically assessed. We aimed to perform a systematic review of the interventional studies that have assessed PA as an outcome in patients with COPD.A systematic search in five different databases (Medline, Embase, PsycINFO, CINAHL and Web of Science) was performed in March 2015. Two independent reviewers analysed the studies against the inclusion criteria (COPD defined by spirometry; prospective, randomised/nonrandomised studies, cohort and experimental studies with interventions using PA as an outcome), extracted the data and assessed the quality of evidence.60 studies were included. Seven intervention groups were identified. PA counselling increased PA levels in COPD, especially when combined with coaching. 13 studies showed positive effects of pulmonary rehabilitation (PR) on PA, while seven studies showed no changes. All three PR programmes >12 weeks in duration increased PA. Overall, the quality of evidence was graded as very low.Interventions focusing specifically on increasing PA, and longer PR programmes, may have greater impacts on PA in COPD. Well-designed clinical trials with objective assessment of PA in COPD patients are needed.

The Bland-Altman limits of agreement method is widely used to assess how well the measurements produced by two raters, devices or systems agree with each other. However, mixed effects versions of the method which take into account multiple sources of variability are less well described in the literature. We address the practical challenges of applying mixed effects limits of agreement to the comparison of several devices to measure respiratory rate in patients with chronic obstructive pulmonary disease (COPD). Respiratory rate was measured in 21 people with a range of severity of COPD. Participants were asked to perform eleven different activities representative of daily life during a laboratory-based standardised protocol of 57 minutes. A mixed effects limits of agreement method was used to assess the agreement of five commercially available monitors (Camera, Photoplethysmography (PPG), Impedance, Accelerometer, and Chest-band) with the current gold standard device for measuring respiratory rate. Results produced using mixed effects limits of agreement were compared to results from a fixed effects method based on analysis of variance (ANOVA) and were found to be similar. The Accelerometer and Chest-band devices produced the narrowest limits of agreement (-8.63 to 4.27 and -9.99 to 6.80 respectively) with mean bias -2.18 and -1.60 breaths per minute. These devices also had the lowest within-participant and overall standard deviations (3.23 and 3.29 for Accelerometer and 4.17 and 4.28 for Chest-band respectively). The mixed effects limits of agreement analysis enabled us to answer the question of which devices showed the strongest agreement with the gold standard device with respect to measuring respiratory rates. In particular, the estimated within-participant and overall standard deviations of the differences, which are easily obtainable from the mixed effects model results, gave a clear indication that the Accelerometer and Chest-band devices performed best.

Telehealth programs to promote early identification and timely self-management of acute exacerbations of chronic obstructive pulmonary diseases (AECOPDs) have yielded disappointing results, in part, because parameters monitored (symptoms, pulse oximetry, and spirometry) are weak predictors of exacerbations. Purpose: Breathing rate (BR) rises during AECOPD and may be a promising predictor. Devices suitable for home use to measure BR have recently become available, but their accuracy, acceptability, and ability to detect changes in people with COPD is not known. Patients and methods: We compared five BR monitors, which used different monitoring technologies, with a gold standard (Oxycon Mobile^®; CareFusion^®, a subsidiary of Becton Dickinson, San Diego, CA, USA). The monitors were validated in 21 stable COPD patients during a 57-min “activities of daily living protocol” in a laboratory setting. The two best performing monitors were then tested in a 14-day trial in a home setting in 23 stable COPD patients to determine patient acceptability and reliability of signal. Acceptability was explored in qualitative interviews. The better performing monitor was then given to 18 patients recruited during an AECOPD who wore the monitor to observe BR during the recovery phase of an AECOPD. Results: While two monitors demonstrated acceptable accuracy compared with the gold standard, some participants found them intrusive particularly when ill with an exacerbation, limiting their potential utility in acute situations. A reduction in resting BR during the recovery from an AECOPD was observed in some, but not in all participants and there was considerable day-to-day individual variation. Conclusion: Resting BR shows some promise in identifying exacerbations; however, further prospective study to assess this is required.

Comorbidities are common in patients with chronic obstructive pulmonary disease (COPD) and it plays an important role on physical activity (PA) in this population. Since low PA levels have been described as a key factor to predict morbi-mortality in COPD, it seems crucial to review the current literature available on this topic. Areas covered: This review covers the most common comorbidities found in COPD, their prevalence and prognostic implications. We explore the differences in PA between COPD patients with and without comorbidities, as well as the impact of the number or type of comorbidities on activity levels of this population. The effect of different comorbidities on activities of daily living in patients with COPD is also reviewed. Finally, we discuss options for the treatment of inactivity in COPD patients considering their comorbidities and limitations. Expert commentary: Comorbidities are highly prevalent in patients with COPD and further deteriorate PA levels in this population. Despite the wide range of interventions available in COPD, the evidence in the field seems to point at PA coaching with feedback on individual goals and longer lasting PR programmes with more than 12 weeks of duration when attempting to raise the activity levels of this population.

In adults it is recommended that the minimum of 10,000 steps/day should be performed in order to consider an individual as active. The pedometer, a small device that counts steps, has been used to monitor and/or motivate physical activity in various populations. To investigate the short-term effects of a protocol using a pedometer or an informative booklet to increase daily physical activity in apparently healthy smokers who reached or did not reach the minimum public health recommendation of 10,000 steps/day. Subjects were randomly assigned to 2 groups: group pedometer (GP, n = 23), who wore a pedometer every day during 1 month, aiming to achieve 10,000 steps/day; and group booklet (GB, n = 17), who received a booklet with encouragement to walk as much as possible in everyday life. Each group was subdivided according to their baseline daily physical activity level: active (subjects who achieved 10,000 steps/day), and inactive (those who did not achieve this minimum). Only the physically inactive GP increased significantly its daily physical activity (pre vs post 7,670 [6,159-9,402] steps/day vs 10,310 [9,483-11,110] steps/day, P < .001), with a concomitant increase in the 6-min walking test (6MWT) distance (mean and interquartile range 540 m [501-586 m] vs 566 m [525-604 m], P = .03). In GP, Δ post-pre steps/day correlated significantly with baseline number of steps/day (r = -0.63, P = .01), but not with 6MWT. In the inactive subjects (summing GP and GB), there were significant correlations between steps/day and cigarettes/day, pack-years, and Fagerström questionnaire (r = -0.55, -0.40, and -0.59, P ≤ .05 for all). Furthermore, improvement in steps/day in the inactive subjects of GP was correlated with baseline cigarettes smoked per day, pack-years, and Fagerström questionnaire (r = 0.51, 0.65 and 0.53, P ≤ .05 for all). Physically inactive smokers improve their daily physical activity level by using a simple tool (pedometer), and larger improvement occurs in subjects with the lowest levels of physical activity.