Validation of a compact motion sensor for the measurement of physical activity in patients with chronic obstructive pulmonary disease

Processing of Sedentary Time and Its Reference Equation in Patients with COPD

Purpose

Sedentary time (ST) is associated with mortality independent of moderate-to-vigorous physical activity in patients with COPD. The proper processing methods for the measurement data and factors related to ST are still unknown. We investigated several conditions for determining the proper processing of ST accelerometric data and created a reference equation for ST using ST-related factors.

Patients and Methods

In Study 1, we evaluated the minimum required number of days to obtain repeatability at different measurement times and assessed the effects of rainy days or weekend days on ST in patients with COPD. In Study 2, we detected the ST-related factors among 28 parameters and created a reference equation for ST using the detected factors.

Results

In Study 1, 38 patients with stable COPD were analyzed. The minimum number of days required for repeatability was 3 for 8-h wearing and 2 for 10-h wearing. The ST was significantly prolonged on rainy days, but not on weekends. In Study 2, 216 patients with stable COPD were analyzed. BMI, FEV1%pred, 6MWD, and mMRC were detected as ST-related factors, and a reference equation could be created using these four factors. The equation was validated for patients whose ST was ≥ 6 h.

Conclusion

By using properly processed measurement data of ST, we created a reference equation for assessing ST that is expected to be useful for providing individual guidance on the shortening of ST to patients with COPD.

Phase angle as an indicator of physical activity in patients with stable chronic obstructive pulmonary disease

OBJECTIVES

Phase angle (PhA) reflects cell membrane integrity and vitality and is an indicator of sarcopenia. PhA is associated with physical function in patients with stable chronic obstructive pulmonary disease (COPD). To our knowledge, the association between PhA and physical activity (PA) has not been investigated. Therefore, the aim of this study was to investigate whether PhA reflects PA in patients with COPD.

METHODS

This single-center, cross-sectional, observational study included 103 patients with stable COPD (87 men; mean age, 74.7 ± 8.1 y; mean forced expiratory volume in 1s %predicted value, 58.9 ± 20.4%). PhA was measured by bioelectrical impedance analysis. Patients were stratified into low (n = 54) and high (n = 49) PhA groups based on median values (4.3° ± 0.6° and 5.4° ± 0.5°, respectively). PA was calculated as the average daily duration of high-intensity light PA (HLPA; 2.0-2.9 metabolic equivalents [METs] of PA) and moderate- to vigorous-intensity PA (MVPA; >3 METs). Correlation and multivariate analyses using multiple regression analysis were performed to confirm the association between PhA and PA.

RESULTS

The high-PhA group demonstrated greater HLPA (104.4 [16.5-332.5] versus 131.3 [61.1-328.7] min, P = 0.005) and MVPA (19.5 [4.7-96.0] versus 46.6 [8.9-139.3] min, P < 0.001) than the low-PhA group. PhA was positively correlated with HLPA (r = 0.32, P < 0.001) and MVPA (r = 0.49, P < 0.001). MVPA (β = 0.178, P = 0.029) and HLPA (β = 0.158, P = 0.026) were associated with PhA independent of age, sex, body mass index, respiratory function, muscle strength, skeletal muscle mass index, and 6-min walking distance.

CONCLUSION

In patients with COPD, PhA may reflect PA as well as muscle function.

A cross-sectional survey on the effects of ambient temperature and humidity on health outcomes in individuals with chronic respiratory disease

Rationale

Extremes of temperature and humidity are associated with adverse respiratory symptoms, reduced lung function, and increased exacerbations among individuals living with chronic obstructive pulmonary disease (COPD).

Objectives

To describe the reported effects of temperature and humidity extremes on the health outcomes, health status and physical activity (PA) in individuals living with COPD.

Methods

A cross-sectional self-reported survey collected the effects on health status (COPD Assessment Test [CAT]), PA, and health outcomes in 1) moderate/ideal (14 to 21°C, 30 to 50% relative humidity [RH]), 2) hot and humid (≥ 25°C, > 50% RH) and 3) cold and dry (≤ 5°C, < 30% RH) weather conditions. Participants were ≥ 40 years old with COPD or related chronic respiratory diseases (e.g., asthma, sleep apnea, interstitial lung disease, lung cancer) and residing in Canada for ≥ 1 year. Negative responders to weather extremes were a priori defined as having a change of ≥ 2 points in the CAT.

Main Results

Thirty-six participants responded; the mean age (SD) was 65 (11) years, and 23 (64%) were females. Compared to ideal conditions, 23 (66%) and 24 (69%) were negatively affected by cold/dry and hot/humid weather, respectively. Health status was significantly lower, and PA amount and difficulty level were reduced in hot/humid and cold/dry conditions compared with ideal conditions. The number of exacerbations in hot/humid was significantly higher compared to ideal conditions.

Conclusions

More participants were negatively affected by extremes of weather: health status worsened, PA decreased, and frequency of exacerbations was higher compared to ideal. Future prospective studies should directly and objectively investigate different combinations of extreme temperature and humidity levels on symptoms and PA to understand their long-term health outcomes.

Utility of the Shortness of Breath in Daily Activities Questionnaire (SOBDA-Q) to Detect Sedentary Behavior in Patients with Chronic Obstructive Pulmonary Disease (COPD)

Sedentary behavior has been shown to be an independent predictor of mortality in patients with chronic obstructive pulmonary disease (COPD). However, physicians have difficulty ascertaining patients' activity levels because they tend to avoid shortness of breath. The reformed shortness of breath (SOB) in the daily activities questionnaire (SOBDA-Q) specifies the degree of SOB by measuring low-intensity activity behavior in everyday living. Therefore, we aimed to explore the utility of the SOBDA-Q in detecting sedentary COPD. We compared the modified Medical Research Council dyspnea scale (mMRC), COPD assessment test (CAT), and SOBDA-Q with physical activity levels (PAL) in 17 healthy patients, 32 non-sedentary COPD patients (PAL ≥ 1.5 METs·h), and 15 sedentary COPD patients (PAL < 1.5 METs·h) in this cross-sectional study. CAT and all domains of the SOBDA-Q in all patients are significantly correlated with PAL, even after adjusting for age. The dietary domain has the highest specificity, and the outdoor activity domain has the highest sensitivity for detecting sedentary COPD. Combining these domains helped determine patients with sedentary COPD (AUC = 0.829, sensitivity = 1.00, specificity = 0.55). The SOBDA-Q is associated with PAL and could be a useful tool for determining patients with sedentary COPD. Moreover, eating and outing inactivity claims reflect sedentary behavior in patients with COPD.

Objective Measurement of Physical Activity and Sedentary Behavior in Patients with Chronic Obstructive Pulmonary Disease: Points to Keep in Mind during Evaluations

Objective measurement methods using accelerometers have become the mainstream approach for evaluating physical activity (PA) and sedentary behavior (SB). However, several problems face the objective evaluation of PA and SB in patients with chronic obstructive pulmonary disease (COPD). For example, indicators of PA differ depending on whether the accelerometer detects the kind of activity on the one hand, or its intensity on the other. Measured data are also strongly influenced by environmental factors (weather, season, employment status, etc.) and methodological factors (days with uncommon activities, non-wearing time, minimum required wearing time per day, minimum number of valid days required, etc.). Therefore, adjusting for these factors is required when evaluating PA or SB, especially when evaluating the effects of intervention. The exclusion of sleeping time, unification of total measurement time, and minimization of the required wearing time per day might be more important for the evaluation of ST than for evaluating PA. The lying-down-time-to-sitting-time ratio was shown to be larger in COPD patients than in healthy subjects. In this review, we clarified the problems encountered during objective evaluations of PA and SB in patients with COPD and encouraged investigators to recognize the presence of these problems and the importance of adjusting for them.

Impact of non-exercise activity thermogenesis on physical activity in patients with COPD

Physical inactivity is associated with comorbidities and mortality in chronic obstructive pulmonary disease (COPD) patients. Although non-exercise activity thermogenesis (NEAT) is important for evaluating the physical activity level (PAL) of patients with chronic diseases, it has not yet been assessed in COPD patients. This study included male patients with COPD (n = 28) and high risk for COPD (n = 8). Total energy expenditure (TEE) and basal metabolic rate (BMR) were measured using the doubly labeled water (DLW) method and indirect calorimetry, respectively. PAL was calculated as TEE/BMR, while the NEAT was obtained from a questionnaire. Physical activity was also assessed using an accelerometer. The total NEAT score was correlated with PAL (r = 0.534, P < 0.001), while PAL was correlated more strongly with the non-locomotive NEAT score (r = 0.548, P < 0.001) than the locomotive NEAT score (r = 0.278, P = 0.10). Regarding accelerometer-obtained data, this questionnaire mainly reflected steps/day and the duration of light locomotive and non-locomotive daily activities. The NEAT score is a possible option for evaluating PAL in daily clinical practice. The present results indicated that non-locomotive activity may have a greater impact on PAL than locomotive activity in COPD patients.

Quality Evaluation of Free-living Validation Studies for the Assessment of 24-Hour Physical Behavior in Adults via Wearables: Systematic Review

Background

Wearable technology is a leading fitness trend in the growing commercial industry and an established method for collecting 24-hour physical behavior data in research studies. High-quality free-living validation studies are required to enable both researchers and consumers to make guided decisions on which study to rely on and which device to use. However, reviews focusing on the quality of free-living validation studies in adults are lacking.

Objective

This study aimed to raise researchers’ and consumers’ attention to the quality of published validation protocols while aiming to identify and compare specific consistencies or inconsistencies between protocols. We aimed to provide a comprehensive and historical overview of which wearable devices have been validated for which purpose and whether they show promise for use in further studies.

Methods

Peer-reviewed validation studies from electronic databases, as well as backward and forward citation searches (1970 to July 2021), with the following, required indicators were included: protocol must include real-life conditions, outcome must belong to one dimension of the 24-hour physical behavior construct (intensity, posture or activity type, and biological state), the protocol must include a criterion measure, and study results must be published in English-language journals. The risk of bias was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool with 9 questions separated into 4 domains (patient selection or study design, index measure, criterion measure, and flow and time).

Results

Of the 13,285 unique search results, 222 (1.67%) articles were included. Most studies (153/237, 64.6%) validated an intensity measure outcome such as energy expenditure. However, only 19.8% (47/237) validated biological state and 15.6% (37/237) validated posture or activity-type outcomes. Across all studies, 163 different wearables were identified. Of these, 58.9% (96/163) were validated only once. ActiGraph GT3X/GT3X+ (36/163, 22.1%), Fitbit Flex (20/163, 12.3%), and ActivPAL (12/163, 7.4%) were used most often in the included studies. The percentage of participants meeting the quality criteria ranged from 38.8% (92/237) to 92.4% (219/237). On the basis of our classification tree to evaluate the overall study quality, 4.6% (11/237) of studies were classified as low risk. Furthermore, 16% (38/237) of studies were classified as having some concerns, and 72.9% (173/237) of studies were classified as high risk.

Conclusions

Overall, free-living validation studies of wearables are characterized by low methodological quality, large variability in design, and focus on intensity. Future research should strongly aim at biological state and posture or activity outcomes and strive for standardized protocols embedded in a validation framework. Standardized protocols for free-living validation embedded in a framework are urgently needed to inform and guide stakeholders (eg, manufacturers, scientists, and consumers) in selecting wearables for self-tracking purposes, applying wearables in health studies, and fostering innovation to achieve improved validity.

Post-operative, inpatient rehabilitation after lung transplant evaluation (PIRATE): A feasibility randomized controlled trial

BACKGROUND

Postoperative rehabilitation is crucial following lung transplantation (LTx); however, it is unclear whether intensive rehabilitation is feasible to deliver in the acute setting. We aimed to establish the feasibility and safety of intensive acute physiotherapy post-LTx.

METHODS

This feasibility trial randomized 40 adults following bilateral sequential LTx to either standard (once-daily) or intensive (twice-daily) physiotherapy. Primary outcomes were feasibility (recruitment and delivery of intensive intervention) and safety. Secondary outcomes included six-minute walk test; 60-second sit-to-stand; grip strength; physical activity; pain; EQ-5D-5L; length of stay; and readmissions. Data were collected at baseline, week 3, and week 10 post-LTx. ClinicalTrials.gov #NCT03095859.

RESULTS

Of 83 LTx completed during the trial, 49% were eligible and 48% provided consent. Median age was 61 years {range 18-70}; waitlist time 85 days [IQR 35-187]. Median time to first mobilization was 2 days [2-3]. Both groups received a median of 10 [7-14] standard interventions post-randomization. A median of 9 [6-18] individual intensive interventions were attempted (86% successful), the most common barrier being medical procedures/investigations (67%). No intervention-related adverse events or between-group differences in secondary outcomes were observed.

CONCLUSIONS

Acute, intensive physiotherapy was feasible and safe post-LTx. This trial provides data to underpin definitive trials to establish efficacy.

Factors Associated with Reduction of Sedentary Time Following Tiotropium/Olodaterol Therapy in Treatment-Naïve Chronic Obstructive Pulmonary Disease

Background

Prolonged sedentary behavior is associated with worse prognosis in patients with chronic obstructive pulmonary disease (COPD). Our previous study found that first-line dual therapy with tiotropium/olodaterol significantly reduces sedentary time compared to tiotropium monotherapy in Japanese patients with treatment-naïve COPD, although the characteristics of responders to dual-therapy versus monotherapy for COPD are still unclear.

Methods

Patients with treatment-naïve COPD were randomized to receive either tiotropium or tiotropium/olodaterol treatment for 12 weeks. Physical activity was assessed using a triaxle accelerometer for 2 weeks before and after treatment. This analysis focused on the change in sedentary time, indicated by physical activity of 1.0–1.5 metabolic equivalents (METs), with stratification for the following factors: age, body mass index (BMI), pulmonary function, COPD assessment test (CAT), the 6-minute walk distance (6MWD), and physical activity level at study entry.

Results

Thirty-five patients received tiotropium/olodaterol and 34 patients received tiotropium. In patients with lower inspiratory capacity at study entry, a significant reduction in sedentary time was observed in the tiotropium/olodaterol group compared with the tiotropium group (Tio: −12.8 ± 13.5 min, Tio/Olo: −65.1 ± 21.0 min, mean difference, −52.2 min, 95% CI −103.6 to 0.88, p = 0.046). In patients with a shorter duration of physical activity of ≥2 METs at study entry, a significant reduction of sedentary time was observed in the tiotropium/olodaterol group compared with the tiotropium group (Tio: −3.3 ± 17.5 min, Tio/Olo: −72.9 ± 23.1 min, mean difference, −69.7 min, 95% CI −128.7 to −10.6, p = 0.02). There were no differences in terms of age, BMI, CAT score, 6MWD, FEV1, FVC, VC, and physical activity of 1.0–1.5 METs and ≥3.0 METs.

Conclusion

This study showed that COPD patients with lower inspiratory capacity or shorter active time of ≥2.0 METs at study entry are likely to exhibit significantly greater reduction in sedentary time with tiotropium/olodaterol treatment.

Reference Equations for Assessing the Physical Activity of Japanese Patients with Chronic Obstructive Pulmonary Disease

Background

To improve physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD), providing a target PA value based on the individual patient's condition may be a useful interventional strategy. However, to determine the target value, a predictive PA value for each patient is required.

Research Question

What is the reference equation consisting of PA-related factors to determine the predictive PA value for each patient with COPD?

Material and Methods

In this prospective cross-sectional observational study, we measured the PA with a triaxial accelerometer and several other factors including demographic factors, pulmonary function, dyspnea, exercise capacity, muscle strength, nutrition, and indicators of several comorbidities in stable Japanese outpatients with COPD aged ≥40 years old and detected PA-related factors by a multiple regression analysis and stepwise method. We created reference equations for four indices of PA using multiple linear regression equations.

Results

Two hundred and twenty-seven patients were registered. The equations of duration at ≥2.0 metabolic equivalents (METs) and step count consisted of 4 factors: 6-minute walk distance, modified Medical Research Council dyspnea scale, anxiety score of the Hospital Anxiety and Depression Scale, and the forced expiratory volume in 1 second % of predicted value. Those of duration at ≥3.0 METs and total activity at ≥3.0 METs consisted of 5 factors: the above 4 factors and age or brain natriuretic peptide. There was no fixed bias or proportional bias between the measured and predictive values in patients with non-high measured PA values.

Conclusion

We determined reference equations for four indicators of PA using PA-related factors in Japanese patients with COPD. The predictive values calculated using the equations could be useful for deciding target PA values for each patient.

Clinical Trial Registration

UMIN-CTR; No.: UMIN000025459; URL: https://www.umin.ac.jp/ctr/index.htm.

Longitudinal Relationship Between Growth Differentiation Factor 11 and Physical Activity in Chronic Obstructive Pulmonary Disease

BACKGROUND

Daily physical activity is reduced in patients with chronic obstructive pulmonary disease (COPD) and a reduced level of physical activity has been shown to be an important predictor for the prognosis, such as increased risk of exacerbation and mortality. However, there has not yet been a useful biomarker of the physical activity. In our previous cross-sectional study, we showed that the level of one of the possible myokines, which is an anti-aging factor, growth differentiation factor 11 (GDF11), was decreased in the plasma from patients with COPD and correlated with the physical activity. To clarify this relationship, we conducted a longitudinal evaluation of such factors.

PATIENTS AND METHODS

Twenty-four COPD patients were enrolled and prospectively followed. We measured the levels of plasma GDF11 and systemic inflammatory markers with immunoblotting or ELISA, respectively. We also evaluated lung function and daily physical activity using a triaxial accelerometer and the incidence of exacerbation.

RESULTS

The change in the plasma level of GDF11, but not systemic inflammatory markers, was positively correlated with the change in the physical activity in an intensity-dependent manner (between the change in the number of steps and GDF11; r = 0.41, p = 0.047). In the multiple regression analysis, the relationship was confirmed (β = 0.93, p < 0.001). In addition, patients who maintained their plasma level of GDF11 showed a significantly lower incidence in exacerbations of COPD than those with decreased levels of GDF11 (p = 0.041).

CONCLUSION

The longitudinal change in the plasma level of GDF11 was positively correlated with the change in the daily physical activity in COPD. GDF11 could be a useful humoral factor that reflects the physical activity in COPD.

Seasons, weather, and device-measured movement behaviors: a scoping review from 2006 to 2020

BACKGROUND

This scoping review summarized research on (a) seasonal differences in physical activity and sedentary behavior, and (b) specific weather indices associated with those behaviors.

METHODS

PubMed, CINAHL, and SPORTDiscus were searched to identify relevant studies. After identifying and screening 1459 articles, data were extracted from 110 articles with 118,189 participants from 30 countries (almost exclusively high-income countries) on five continents.

RESULTS

Both physical activity volume and moderate-to-vigorous physical activity (MVPA) were greater in summer than winter. Sedentary behavior was greater in winter than either spring or summer, and insufficient evidence existed to draw conclusions about seasonal differences in light physical activity. Physical activity volume and MVPA duration were positively associated with both the photoperiod and temperature, and negatively associated with precipitation. Sedentary behavior was negatively associated with photoperiod and positively associated with precipitation. Insufficient evidence existed to draw conclusions about light physical activity and specific weather indices. Many weather indices have been neglected in this literature (e.g., air quality, barometric pressure, cloud coverage, humidity, snow, visibility, windchill).

CONCLUSIONS

The natural environment can influence health by facilitating or inhibiting physical activity. Behavioral interventions should be sensitive to potential weather impacts. Extreme weather conditions brought about by climate change may compromise health-enhancing physical activity in the short term and, over longer periods of time, stimulate human migration in search of more suitable environmental niches.

Impact of Proactive Integrated Care on Chronic Obstructive Pulmonary Disease

Background

Up to 50% of chronic obstructive pulmonary disease (COPD) patients do not receive recommended care for COPD. To address this issue, we developed Proactive Integrated Care (Proactive iCare), a health care delivery model that couples integrated care with remote monitoring.

Methods

We conducted a prospective, quasi-randomized clinical trial in 511 patients with advanced COPD or a recent COPD exacerbation, to test whether Proactive iCare impacts patient-centered outcomes and health care utilization. Patients were allocated to Proactive iCare (n=352) or Usual Care ( =159) and were examined for changes in quality of life using the St George's Respiratory Questionnaire (SGRQ), symptoms, guideline-based care, and health care utilization.

Findings

Proactive iCare improved total SGRQ by 7-9 units (p < 0.0001), symptom SGRQ by 9 units (p<0.0001), activity SGRQ by 6-7 units (p<0.001) and impact SGRQ by 7-11 units (p<0.0001) at 3, 6 and 9 months compared with Usual Care. Proactive iCare increased the 6-minute walk distance by 40 m (p<0.001), reduced annual COPD-related urgent office visits by 76 visits per 100 participants (p<0.0001), identified unreported exacerbations, and decreased smoking (p=0.01). Proactive iCare also improved symptoms, the body mass index-airway obstruction-dyspnea-exercise tolerance (BODE) index and oxygen titration (p<0.05). Mortality in the Proactive iCare group (1.1%) was not significantly different than mortality in the Usual Care group (3.8%; p=0.08).

Interpretation

Linking integrated care with remote monitoring improves the lives of people with advanced COPD, findings that may have been made more relevant by the coronavirus 2019 (COVID-19) pandemic.

A Non-Interventional, Cross-Sectional Study to Evaluate Factors Relating to Daily Step Counts and Physical Activity in Japanese Patients with Chronic Obstructive Pulmonary Disease: STEP COPD

Purpose

Patients with chronic obstructive pulmonary disease (COPD) have decreased physical activity (PA) compared with healthy adults. As lower PA is associated with increased mortality, improving PA is an important objective for COPD management. This large-scale, multicenter, non-interventional, cross-sectional study examined the activity status of COPD patients in Japan and explored factors related to PA.

Patients and Methods

Outpatients aged ≥40 years with confirmed COPD diagnosis and pulmonary function test data were enrolled. Primary study outcomes were measurement of daily steps (over 14 consecutive days, using an activity monitor), assessment of activity time by activity intensity (using metabolic equivalents [METs]), and evaluation of correlation between PA and patient characteristics. Secondary outcomes included further investigation of the influence of patient characteristics on PA.

Results

Data from 417 patients with Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages I (29.5%), II (43.9%), III (23.5%), and IV (3.1%) were evaluated. Median (Q1, Q3) daily step count was 3440.8 (1831.3, 5709.3). Median (Q1, Q3) durations of PA at ≥3 (moderate-to-vigorous) and ≥2 METs (light-to-vigorous) were 18.7 (6.5, 41.3) and 186.9 (126.9, 259.2) minutes, respectively. For >30% of patients, time spent in ≥3 METs activity was ≤10 minutes. Unemployment was significantly correlated with reduced activity time (≥3 and ≥2 METs) and step count. Severe GOLD stage was significantly correlated with reduced activity time (≥3 and ≥2 METs). High modified Medical Research Council (mMRC) dyspnea score was significantly correlated with reduced activity time (≥3 METs) and step count. Patients tended to overestimate the time spent in activities requiring ≥2 METs in their subjective reports compared with activity monitor measurements.

Conclusion

Reduced PA was observed in the Japanese COPD patients with the majority of them being GOLD stage I/II. Employment status, GOLD stage, and mMRC dyspnea score could help identify patients at risk of reduced PA.

Clinical Trial Registration

NCT03642613 (ClinicalTrials.gov); UMIN000032962 (UMIN-CTR, umin.ac.jp).

Data Reproducibility and Effectiveness of Bronchodilators for Improving Physical Activity in COPD Patients

Increasing physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD) is an important issue, however, the effect of bronchodilators on PA is still controversial. The indicators of PA, as measured by an accelerometer, can easily fluctuate based on several factors, which might cause inconsistent results. In this review, we listed the indicators of PA and the factors influencing the reproducibility of indicators of PA, and reviewed reports in which the effects of bronchodilators on PA were evaluated by an accelerometer. Then, we investigated the association between the processing of influencing factors and the effectiveness of bronchodilators for improving the PA of COPD patients. Fifteen reports were extracted using the PubMed database. In all seven reports in which adjustment was performed for at least two of four influencing factors (non-wear time, data from days with special behavior, environmental factors, and number of valid days required to obtain reproducible data), bronchodilators showed beneficial effects on PA. No adjustment was made for any of these factors in any of the four bronchodilator-ineffective reports. This suggests that the processing of influencing factors to secure reproducibility might affect the results regarding the effectiveness of bronchodilators for improving PA in COPD patients.

The Use of Inertial Measurement Units for the Study of Free Living Environment Activity Assessment: A Literature Review

This article presents an overview of fifty-eight articles dedicated to the evaluation of physical activity in free-living conditions using wearable motion sensors. This review provides a comprehensive summary of the technical aspects linked to sensors (types, number, body positions, and technical characteristics) as well as a deep discussion on the protocols implemented in free-living conditions (environment, duration, instructions, activities, and annotation). Finally, it presents a description and a comparison of the main algorithms and processing tools used for assessing physical activity from raw signals.

First-Line Treatment with Tiotropium/Olodaterol Improves Physical Activity in Patients with Treatment-Naïve Chronic Obstructive Pulmonary Disease

Background

Comparative effects on physical activity of mono and dual bronchodilators remain unclear in patients with treatment-naïve chronic obstructive pulmonary disease (COPD). We sought to compare the changes in physical activity before and after tiotropium and tiotropium/olodaterol treatment in treatment-naïve COPD patients.

Methods

A prospective, multicenter, randomized, open-labeled, and parallel interventional study was conducted. Eighty Japanese patients with treatment-naïve COPD were randomized to receive either tiotropium or tiotropium/olodaterol treatment for 12 weeks. Spirometry and dyspnea index were assessed, and COPD assessment test (CAT) and the 6-minute walk distance (6MWD) were conducted before and after treatment. Evaluation of physical activity was assessed by a triaxle accelerometer over a 2-week period before and after treatment.

Results

There were no differences in the mean age (69.8 vs 70.4 years), body mass index (BMI) (22.5 vs 22.6 kg/m²) and mean % forced expiratory volume in 1 second (%FEV1) at baseline (61.5 vs 62.6%) between the two groups. Changes in FEV1 (mean±standard error, 242.8±28.8 mL) and transient dyspnea index (TDI) (2.4±0.3 points) before and after tiotropium/olodaterol treatment were greater than with tiotropium treatment (104.1±31.9 mL, p<0.01 and 1.5±0.3, p=0.02, respectively). Changes in the duration of physical activity with 1.0–1.5 metabolic equivalents (METs) estimated in the sedentary position following tiotropium/olodaterol treatment (−38.7±14.7 min) tended to be reduced more than with tiotropium treatment (−4.6±10.6 min) (p=0.06), although those with ≥2.0 METs numerically increased with both treatments (+10.8±7.6 min for tiotropium/olodaterol vs +8.3±7.6 min for tiotropium, p=0.82). Tiotropium/olodaterol treatment reduced the duration of physical activity with 1.0–1.5 METs (regression coefficient, −43.6 [95% CI −84.1, −3.1], p=0.04) in a multiple regression model adjusted for cofounding factors such as age, FEV1, total CAT scores, 6MWD, and TDI.

Conclusion

This is the first study to report the impact of dual bronchodilator on physical activity in treatment-naïve COPD patients of Japanese with low BMI.

Comorbid Conditions in Chronic Obstructive Pulmonary Disease: Potential Therapeutic Targets for Unmet Needs

The management of chronic obstructive pulmonary disease (COPD) has improved significantly due to advances in therapeutic agents, but it has also become apparent that there are issues that remain difficult to solve with the current treatment algorithm. COPD patients face a number of unmet needs concerning symptoms, exacerbations, and physical inactivity. There are various risk factors and triggers for these unmet needs, which can be roughly divided into two categories. One is the usual clinical characteristics for COPD patients, and the other is specific clinical characteristics in patients with comorbid conditions, such as asthma, cardiovascular disease, and bronchiectasis. These comorbidities, which are also associated with the diversity of COPD, can cause unmet needs resistance to usual care. However, treatable conditions that are not recognized as therapeutic targets may be latent in patients with COPD. We again realized that treatable traits should be assessed and treated as early as possible. In this article, we categorize potential therapeutic targets from the viewpoint of pulmonary and systemic comorbid conditions, and address recent data concerning the pathophysiological link with COPD and the impact of intervention on comorbid conditions in order to obtain evidence that could enable us to provide personalized COPD management.

A Novel Role of Growth Differentiation Factor (GDF)-15 in Overlap with Sedentary Lifestyle and Cognitive Risk in COPD

Sedentary behavior and cognitive impairment have a direct impact on patients' outcomes. An energy metabolic disorder may be involved in the overlap of these comorbid conditions (motoric cognitive risk (MCR)) in patients with chronic obstructive pulmonary disease (COPD). We aimed to explore the linkage between a proapoptotic protein, growth differentiation factor (GDF)-15, and MCR. Physical activity (PA), cognitive function (Japanese version of the Montreal Cognitive Assessment: MOCA-J), and the serum GDF-15 levels were assessed in healthy subjects (n = 14), asthmatics (n = 22), and COPD patients (n = 28). In the entire cohort, serum GDF-15 had negative correlations with exercise (Ex) (ρ = -0.43, p < 0.001) and MoCA-J (ρ = -0.44, p < 0.001), and Ex and MOCA-J showed a positive correlation (ρ = 0.52, p < 0.0001). Compared to healthy subjects and asthmatics, COPD patients showed the highest serum GDF-15 levels and had a significantly higher proportion of subjects with MCR (both sedentary lifestyle (EX < 1.5) and cognitive risk (MoCA-J ≤ 25)). Also, we found that serum GDF-15 has a screening potential (100% sensitivity) greater than aging (67% sensitivity) for detecting MCR in COPD patients. In conclusion, higher serum GDF-15 had interrelationships with a sedentary lifestyle and cognitive risk. This protein was not disease-specific but could be a screening biomarker to detect MCR related to poor health outcomes of COPD patients.

Validity and Reliability of Accelerometers in Patients With COPD: A SYSTEMATIC REVIEW

PURPOSE

Reduced physical activity is associated with poor prognosis in chronic obstructive pulmonary disease (COPD). Accelerometers have greatly improved quantification of physical activity by providing information on step counts, body positions, energy expenditure, and magnitude of force. The purpose of this systematic review was to compare the validity and reliability of accelerometers used in patients with COPD.

METHODS

An electronic database search of MEDLINE and CINAHL was performed. Study quality was assessed with the Strengthening the Reporting of Observational Studies in Epidemiology checklist while methodological quality was assessed using the modified Quality Appraisal Tool for Reliability Studies.

RESULTS

The search yielded 5392 studies; 25 met inclusion criteria. The SenseWear Pro armband reported high criterion validity under controlled conditions (r = 0.75-0.93) and high reliability (ICC = 0.84-0.86) for step counts. The DynaPort MiniMod demonstrated highest concurrent validity for step count using both video and manual methods.

DISCUSSION

Validity of the SenseWear Pro armband varied between studies especially in free-living conditions, slower walking speeds, and with addition of weights during gait. A high degree of variability was found in the outcomes used and statistical analyses performed between studies, indicating a need for further studies to measure reliability and validity of accelerometers in COPD.

CONCLUSION

The SenseWear Pro armband is the most commonly used accelerometer in COPD, but measurement properties are limited by gait speed variability and assistive device use. DynaPort MiniMod and Stepwatch accelerometers demonstrated high validity in patients with COPD but lack reliability data.

Simple standard equation for daily step count in Japanese patients with chronic obstructive pulmonary disease

Purpose

The improvement of physical activity in patients with COPD is an important issue. However, no standard for the recommended number of steps for patients with COPD has been determined. We conducted a retrospective observational study to create a simple standard equation for the daily step count, which makes it easier to determine whether each subject is attaining his/her predicted value or not.

Patients and methods

Stable outpatients diagnosed with COPD whose physical activities had been measured using a triaxial accelerometer for more than 2 weeks were recruited from 5 institutes in Japan. Factors associated with the step count were detected by multivariate regression analysis. After the data were transformed to a normalized distribution, a multivariate linear regression equation was created using stepwise regression.

Results

One hundred sixty-two patients aged 72.3 (7.2) years and of FEV1 %pred 59.2 (22.8) % were recruited. Among the parameters, age, mMRC dyspnea scale and inspiratory capacity (IC) were detected by the stepwise method. The created standard equation was “Step count = (−0.079×[age]−1.595×[mMRC]+2.078×[IC]+18.149)³”. The correlations between the calculated values and the measured values were observed, and fixed, and proportional biases between them were also observed. When patients with <6500 steps/day were selected, no systematic bias between them could be detected.

Conclusion

A simple standard equation for Japanese patients with COPD was created using age, mMRC and IC, and could provide an individual-predicted value, especially for patients with <6500 steps/day.

Effect of tiotropium/olodaterol on sedentary and active time in patients with COPD: post hoc analysis of the VESUTO® study

Background

Patients with COPD are less physically active. This post hoc analysis of a randomized, double-blind, active-controlled, crossover trial assessed the efficacy of once-daily tiotropium/olodaterol combination therapy versus tiotropium monotherapy in Japanese patients with COPD.

Patients and methods

Patients were provided with a three-axis accelerometer to measure sedentary and active behavior defined as 1.0-1.5 metabolic equivalents (METs), ≥2.0 METs, and ≥3.0 METs, respectively. Of the 182 patients enrolled, 131 satisfied the conditions for the present analysis and were randomized to tiotropium monotherapy (n=62) or tiotropium/olodaterol combination therapy (n=69).

Results

Tiotropium/olodaterol combination therapy significantly reduced the duration of 1.0-1.5 MET activity by 8.64 mins (p=0.040) and significantly increased the duration of ≥2.0 MET and ≥3.0 MET activity by 6.51 mins (p=0.017) and 2.60 mins (p=0.008), respectively, compared with tiotropium alone. Subgroup analyses showed that better lung function, milder dyspnea, and higher levels of physical activity at baseline were associated with reduced sedentary time and increased duration of physical activity.

Conclusion

Tiotropium/olodaterol combination therapy significantly reduced sedentary time and improved physical activity compared with tiotropium monotherapy. This trial was registered in ClinicalTrials.gov (NCT02629965).

Combination of assist use of short-acting beta-2 agonists inhalation and guidance based on patient-specific restrictions in daily behavior: Impact on physical activity of Japanese patients with chronic obstructive pulmonary disease

BACKGROUND

Assist use of inhaled short-acting beta 2 agonists (SABAs) is reportedly effective for preventing shortness of breath on exertion in chronic obstructive pulmonary disease (COPD) patients. However, it is unclear what strategy would be useful for improving physical activity in such patients. The aim is to investigate the effects of assisted use of SABA (procaterol) on physical activity in Japanese COPD patients targeting patient-specific restrictions in daily behavior.

METHODS

Fourteen patients with stable COPD (age: 72.1±1.5, %FEV₁: 55.6±4.5%) were asked to inhale 20 μg of procaterol 15 minutes before patient-specific daily physical activity that had been identified as limited by a questionnaire and document their usage in a diary. Physical activity was measured using a triaxial accelerometer and the results were collected every month for 2 months. In the first month, a clinician assessed whether inhalation of SABA was appropriate based on a usage diary and coached patients to conduct adequate assist use of SABA for limited physical activity.

RESULTS

The strategy significantly improved the physical activity level, assessed using the values of the metabolic equivalents (METs) multiplied by physical activity endurance, at ≥3.0 METs (p<0.05), and physical activity endurance at ≥2.5 and ≥3.0 METs, (p<0.05, p<0.05, respectively). The degree of improvement of physical activity level was significantly positively correlated with the baseline %FVC and %FEV₁ (p<0.05, p<0.05, respectively).

CONCLUSIONS

Assist use of SABA targeting patient-specific restrictions, particularly when better lung function is still preserved, could be a useful approach for improving physical activity in patients with COPD.

Physical inactivity is associated with decreased growth differentiation factor 11 in chronic obstructive pulmonary disease

BACKGROUND

Growth differentiation factor 11 (GDF11) is reported to possess anti-aging and rejuvenating effects, including muscle regeneration and to be highly expressed in skeletal muscle. Recently, we demonstrated that the levels of plasma GDF11 were decreased in COPD. However, the effect of decreased circulating GDF11 in the pathophysiology of COPD remains unknown. The aim of this study is to investigate the association between the plasma GDF11 levels and various clinical parameters in patients with COPD.

PATIENTS AND METHODS

Eighteen ex-smokers as control subjects and 70 COPD patients participated in the current study. We measured the levels of plasma GDF11 using immunoblotting, lung function, physical activity using a triaxial accelerometer, quadriceps strength, exercise capacity, and systemic inflammatory markers. We investigated the association between the levels of plasma GDF11 and these clinical parameters.

RESULTS

The levels of plasma GDF11 in the COPD patients had significant positive correlations with the data of lung function. Furthermore, the levels of plasma GDF11 were significantly correlated with the physical activity, quadriceps strength, and exercise capacity. Moreover, the levels of plasma GDF11 were significantly correlated with the data of inflammatory markers. Although various factors were related to GDF11, the multiple regression analysis showed that physical activity was significantly associated with the levels of plasma GDF11.

CONCLUSION

Physical inactivity was significantly related to the decreased GDF11 levels in COPD, which might be useful for understanding the pathogenesis of COPD. Clarifying the relationships between the physical inactivity and GDF11 may reveal a potentially attractive therapeutic approach in COPD via increasing the plasma levels of GDF11.

Verification of a Motion Sensor for Evaluating Physical Activity in COPD Patients

Background

Objective evaluation of the physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD) is important. We validated a triaxial accelerometer, Active Style Pro HJA-750C® (HJA), and evaluated the necessary conditions for obtaining reproducible data.

Methods

The PA measured by HJA was compared with that measured by two already validated accelerometers in 11 patients with COPD (age: 76.6 ± 6.9, FEV1% predicted: 57.6 ± 18.6). Then, the influence of weather and holidays on the PA and the required number of days to obtain repeatability were examined in 21 patients with COPD (age: 73.0 ± 8.0, FEV1% predicted: 58.7 ± 19.0).

Results

The PA values measured by HJA and those by DynaPort Move Monitor® (DMM) or Actimarker® (AM) were significantly correlated at all intensities (p=0.024 at ≥4.0 METs by DMM and p < 0.0001 at the rest) except at ≥4.0 METs by AM, though the values measured by HJA were higher than those by AM which was reported to underestimate PA. The durations of PA on rainy days were significantly shorter than those on nonrainy days, but those on holidays were not different from those on weekdays. The values of ICC for 3, 4, or 5 days were higher than 0.8 at all intensities. The PA measured by HJA was correlated with the dyspnea scale FVC and age and tended to correlate with FEV1.

Conclusions

The HJA was validated for evaluating the PA in patients with COPD. This trial is registered with UMIN000016363.

Differences in physical activity according to mMRC grade in patients with COPD

BACKGROUND

Physical activity (PA) is impaired from the early stages of COPD, is associated with a worsening of disease prognosis, and causes COPD patients to restrict their daily activities in order to avoid breathlessness. The development of a simple tool to estimate physical activity level (PAL) could be useful for the management of COPD.

OBJECTIVES

We investigated the differences in PA according to the modified Medical Research Council (mMRC) grade in patients with COPD.

METHODS

A cross-sectional study was performed on stable outpatients with COPD. PA was measured for 2 weeks using a triaxial accelerometer, and dyspnea grade was evaluated in all patients using the mMRC scale.

RESULTS

Ninety-eight patients were recruited. Significant differences in PA duration were observed at all intensities according to the mMRC grade. Despite treatment with controller medications, 59.2% of COPD patients had low PAL, which was <1.5 metabolic equivalents multiplied by hour per day. COPD patients with an mMRC grade ≥2, which was the most balanced cutoff point in the receiver operating characteristic curve, showed a higher reduction rate of PAL (80.0% at mMRC grade 2, 71.4% at mMRC grade 3, and 100% at mMRC grade 4).

CONCLUSION

PA differed according to the mMRC grade, and mMRC grade ≥2 could predict a low PAL. Therefore, assessment of breathlessness by the mMRC questionnaire would be useful to stratify the risks of reduced PA in COPD.

Functional Status Assessment of Patients With COPD: A Systematic Review of Performance-Based Measures and Patient-Reported Measures

Presently, there is no recommendation on how to assess functional status of chronic obstructive pulmonary disease (COPD) patients. This study aimed to summarize and systematically evaluate these measures.Studies on measures of COPD patients' functional status published before the end of January 2015 were included using a search filters in PubMed and Web of Science, screening reference lists of all included studies, and cross-checking against some relevant reviews. After title, abstract, and main text screening, the remaining was appraised using the Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN) 4-point checklist. All measures from these studies were rated according to best-evidence synthesis and the best-rated measures were selected.A total of 6447 records were found and 102 studies were reviewed, suggesting 44 performance-based measures and 14 patient-reported measures. The majority of the studies focused on internal consistency, reliability, and hypothesis testing, but only 21% of them employed good or excellent methodology. Their common weaknesses include lack of checks for unidimensionality, inadequate sample sizes, no prior hypotheses, and improper methods. On average, patient-reported measures perform better than performance-based measures. The best-rated patient-reported measures are functional performance inventory (FPI), functional performance inventory short form (FPI-SF), living with COPD questionnaire (LCOPD), COPD activity rating scale (CARS), University of Cincinnati dyspnea questionnaire (UCDQ), shortness of breath with daily activities (SOBDA), and short-form pulmonary functional status scale (PFSS-11), and the best-rated performance-based measures are exercise testing: 6-minute walk test (6MWT), endurance treadmill test, and usual 4-meter gait speed (usual 4MGS).Further research is needed to evaluate the reliability and validity of performance-based measures since present studies failed to provide convincing evidence. FPI, FPI-SF, LCOPD, CARS, UCDQ, SOBDA, PFSS-11, 6MWT, endurance treadmill test, and usual 4MGS performed well and are preferable to assess functional status of COPD patients.

Factors associated with the effect of pulmonary rehabilitation on physical activity in patients with chronic obstructive pulmonary disease

AIM

Although the effects of pulmonary rehabilitation (PR) have been well defined for chronic obstructive pulmonary disease (COPD), it remains controversial whether PR improves physical activity (PA). The purpose of the present study was to identify factors associated with the effect of PR on PA.

METHODS

This was a prospective study of 29 patients with COPD. They underwent pulmonary rehabilitation twice weekly for 12 weeks, and were assessed using the hospital anxiety and depression score, 6-min walk distance (6MWD), and the St. George Respiratory Questionnaire (SGRQ) before and after they underwent PR. The PA of patients was measured by a three-axis accelerometer. Physical activity level (PAL) was calculated by dividing each patient's total energy expenditure by basal metabolic rate. Correlations between changes in PAL after PR and 6MWD, St. George Respiratory Questionnaire, and hospital anxiety and depression score scores, and clinical parameters, including forced expiratory volume in 1 s were determined.

RESULTS

6MWD was significantly increased, but PAL was unchanged after PR. PAL was positively correlated with 6MWD, but not with percent predicted forced expiratory volume in 1 s nor St. George Respiratory Questionnaire scores before PR. The increase in PAL was negatively correlated with changes in hospital anxiety and depression score anxiety and depression scores, but was not correlated with the change in 6MWD.

CONCLUSIONS

A PR program for COPD patients improved results of the 6MWD, but not PAL. Increased PAL was associated with improvements in anxiety and depression, but not with increased exercise capacity. Treating the depression and anxiety of patients with COPD might not only reduce emotional distress, but also improve their PAL. Geriatr Gerontol Int 2017; 17: 17-23.

Effects of pharmacologic treatment based on airflow limitation and breathlessness on daily physical activity in patients with chronic obstructive pulmonary disease

BACKGROUND

Improvement in the daily physical activity (PA) is important for the management of chronic obstructive pulmonary disease (COPD). However, the effects of pharmacologic treatment on PA are not well understood. We evaluated the effects of additional medications, including bronchodilator with or without inhaled corticosteroid, based on airflow limitation and breathlessness on the PA in COPD patients and the factors that could predict or affect the improvement in PA.

METHODS

A prospective non-randomized observational study was employed. Twenty-one COPD subjects without any other diseases that might reduce PA were recruited. The PA was measured with a triaxial accelerometer for 2 weeks, and pulmonary function tests and incremental shuttle walking tests were administered before and after 4-week treatment with an additional medication.

RESULTS

Bronchodilation was obtained by additional medication. The mean values of PA evaluated by metabolic equivalents (METs) at ≥3.0 METs and the duration of PA at ≥3.0 METs and ≥3.5 METs were improved by medication. The % change in the duration of PA at ≥3.5 METs was significantly correlated with the baseline functional residual capacity (FRC), residual volume, and inspiratory capacity/total lung capacity. However, the % change in the duration of PA at any intensity was not correlated with the % changes of any values of the pulmonary function tests or incremental shuttle walking test except the PA at ≥2.5 METs with FRC.

CONCLUSION

Medication could improve the PA in patients with COPD, especially at a relatively high intensity of activity when medication was administered based on airflow limitation and breathlessness. The improvement was seen in the patients with better baseline lung volume, but was not correlated with the improvements in the pulmonary function tests or exercise capacity.

Effect of a postoperative outpatient pulmonary rehabilitation program on physical activity in patients who underwent pulmonary resection for lung cancer

AIM

Physical activity (PA) has been associated with an improvement in survival for individuals with cancer. However, little is known about the effect of postoperative pulmonary rehabilitation on PA after lobectomy in patients with lung cancer. The present study investigated the effect of outpatient rehabilitation on PA in patients with cancer after lung resection.

METHODS

A total of 19 patients with lung cancer were recruited for this study and completed a preoperative rehabilitation program. One group of nine patients completed a postoperative outpatient pulmonary rehabilitation program (rehabilitation) and another group of 10 patients did not (control), but were similarly followed up. Preoperative lung function, assessed by forced expiratory volume in 1 s (FEV1 ), body mass index (BMI) and St. George's Respiratory Questionnaire (SGRQ) score were not different between groups. PA was measured before and 2 months after surgery using a three-axis accelerometer for 5-6 days. PA level (PAL) was defined as total energy expenditure divided by basal metabolic rate.

RESULTS

Preoperative PAL was not different between groups. However, postoperative versus preoperative PAL was significantly lower in the control versus the rehabilitation group (P < 0.01), and PAL decline was less for the rehabilitation versus the control group (P < 0.001). A subgroup analysis showed improvement in postoperative PAL in rehabilitation patients aged <75 years and older.

CONCLUSIONS

Two months after lung resection surgery, patients had not recovered to the preoperative PAL. However, compared with the control group, there was an improvement in the postoperative PAL in patients, including older patients, who underwent outpatient pulmonary rehabilitation. Geriatr Gerontol Int 2016; 16: 550-555.

Influence of indacaterol on daily physical activity in patients with untreated chronic obstructive pulmonary disease

Background

Indacaterol, a once-daily, long-acting β₂-agonist, may improve not only respiratory function, dyspnea symptoms, and quality of life, but also physical activity for patients with chronic obstructive pulmonary disease (COPD). This study aimed to evaluate the effect of 12-week indacaterol therapy on daytime physical activity in patients with untreated COPD.

Methods

The subjects were stable and untreated COPD outpatients with a percent predicted forced expiratory volume in 1 second (%FEV₁) below 80%. Baseline assessments included clinical assessment, respiratory function testing, arterial blood gas analysis, the COPD assessment test (CAT™), and the Medical Outcomes Study 36-Item Short-Form Health Survey, Japanese version 2 (SF-36v2^®). Patients underwent monitoring by uniaxial accelerometer before and after 12 weeks once-daily inhalation of indacaterol 150 μg/day.

Results

Eighteen patients were evaluable. Patient characteristics included a mean age of 74.2 years, and three patients were current smokers. Indacaterol improved mean (± standard deviation [SD]) %FEV₁ from 55.2% (±17.9%) to 61.0% (±17.3%) (P=0.003), CAT scores from 16.4 (±10.2) points to 12.4 (±8.2) points (P=0.04), some scales of the SF-36v2 (physical component summary, 41.6±9.7 points to 45.1±7.9 points, P=0.03), and number of daily steps (3,311.5±2,103.3 steps/day to 3,841.8±2,096.8 steps/day, P=0.02), but did not affect daily energy expenditure (85.0±77.2 kcal change to 90.9±56.8 kcal, P=0.29) or exercise duration of an intensity of level 1 or more (36.4±23.9 minutes increase to 40.8±21.6 minutes, P=0.12).

Conclusion

Twelve weeks of indacaterol improved respiratory function and quality of life, but did not significantly affect physical activity in patients with moderate-to-severe COPD.

An official European Respiratory Society statement on physical activity in COPD

This European Respiratory Society (ERS) statement provides a comprehensive overview on physical activity in patients with chronic obstructive pulmonary disease (COPD). A multidisciplinary Task Force of experts representing the ERS Scientific Group 01.02 "Rehabilitation and Chronic Care" determined the overall scope of this statement through consensus. Focused literature reviews were conducted in key topic areas and the final content of this Statement was agreed upon by all members. The current knowledge regarding physical activity in COPD is presented, including the definition of physical activity, the consequences of physical inactivity on lung function decline and COPD incidence, physical activity assessment, prevalence of physical inactivity in COPD, clinical correlates of physical activity, effects of physical inactivity on hospitalisations and mortality, and treatment strategies to improve physical activity in patients with COPD. This Task Force identified multiple major areas of research that need to be addressed further in the coming years. These include, but are not limited to, the disease-modifying potential of increased physical activity, and to further understand how improvements in exercise capacity, dyspnoea and self-efficacy following interventions may translate into increased physical activity. The Task Force recommends that this ERS statement should be reviewed periodically (e.g. every 5-8 years).

Physical Activity Monitoring in Patients with Chronic Obstructive Pulmonary Disease

Reduced physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD) is associated with increased morbidity and mortality (e.g. exacerbations) and eventually leads to disability, depression, and social and physical isolation. Measuring PA in this population is important to accurately characterize COPD and to help clinicians during a baseline evaluation and patient follow-up. Also, it may help increase adherence to PA programs. There are reliable objective and subjective methods available to measure PA. Recently, several new monitors have been developed that have improved accuracy of such measurements. Because these devices provide real-time feedback, they may help to improve participant self-motivation strategies and reinforce daily lifestyle modifications, one of the main goals in COPD management. This review focuses on describing available instruments to measure PA, specifically in patients with COPD. The reliability, validity, advantages, limitations, and clinical applications of questionnaires, pedometers, and accelerometers are discussed. Finally, based on current published literature, we propose recommendations about which methods may be most useful in different research or clinical settings.

Standardizing the analysis of physical activity in patients with COPD following a pulmonary rehabilitation program

BACKGROUND

There is a wide variability in measurement methodology of physical activity. This study investigated the effect of different analysis techniques on the statistical power of physical activity outcomes after pulmonary rehabilitation.

METHODS

Physical activity was measured with an activity monitor armband in 57 patients with COPD (mean ± SD age, 66 ± 7 years; FEV1, 46 ± 17% predicted) before and after 3 months of pulmonary rehabilitation. The choice of the outcome (daily number of steps [STEPS], time spent in at least moderate physical activity [TMA], mean metabolic equivalents of task level [METS], and activity time [ACT]), impact of weekends, number of days of assessment, postprocessing techniques, and influence of duration of daylight time (DT) on the sample size to achieve a power of 0.8 were investigated.

RESULTS

The STEPS and ACT (1.6-2.3 metabolic equivalents of task) were the most sensitive outcomes. Excluding weekends decreased the sample size for STEPS (83 vs 56), TMA (160 vs 148), and METS (251 vs 207). Using 4 weekdays (STEPS and TMA) or 5 weekdays (METS) rendered the lowest sample size. Excluding days with < 8 h wearing time reduced the sample size for STEPS (56 vs 51). Differences in DT were an important confounder.

CONCLUSIONS

Changes in physical activity following pulmonary rehabilitation are best measured for 4 weekdays, including only days with at least 8 h of wearing time (during waking hours) and considering the difference in DT as a covariate in the analysis.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00948623; URL: www.clinicaltrials.gov.

Circulating adiponectin levels are associated with peak oxygen uptake in Japanese

OBJECTIVE

The aim of this study was to investigate the link between circulating adiponectin levels and peak oxygen uptake and/or physical activity in Japanese.

METHODS

A total of 528 subjects (188 men and 340 women) were enrolled in this cross-sectional study. Circulating adiponectin levels, physical activity measured by tri-axial accelerometers, peak oxygen uptake and metabolic risk parameters were evaluated. We also assessed anthropometric factors, blood pressure, blood examinations and energy intake.

RESULTS

Circulating adiponectin levels were 6.7 ± 3.0 μg/mL in men and 11.0 ± 4.9 μg/mL in women. Circulating adiponectin levels were positively correlated with physical fitness after adjusting for age, physical activity evaluated by Σ [metabolic equivalents × h per week (METs h/w)], cigarette smoking habit and energy intake in both sexes. However, these associations were attenuated further after adjusting for body mass index including other confounding factors, especially in men. However, circulating adiponectin levels were not associated with physical activity in either sex.

CONCLUSION

Circulating adiponectin levels were associated with peak oxygen uptake rather than physical activity.

Evaluation of physical activity and its relationship to health-related quality of life in patients on chronic hemodialysis

OBJECTIVE

The aim of this study was to investigate the relationship between physical activity and health-related quality of life (HRQOL) in patients on chronic hemodialysis.

METHODS

A total of 31 men (69.0 ± 11.1 years) and 17 women (66.9 ± 10.0 years) among 61 male and 30 female patients on chronic hemodialysis at Innoshima General Hospital, Onomichi, Japan, were enrolled in this cross-sectional study. Physical activity was evaluated using tri-axial accelerometers. HRQOL and psychological distress were also evaluated using the EuroQol questionnaire (EQ-5D) and the K6 questionnaire, respectively.

RESULTS

Physical activity evaluated by Σ[metabolic equivalents × h per week (METs·h/w)] was 8.1 ± 6.0 METs·h/w, and EQ-5D score was 0.754 ± 0.177. Among all patients, EQ-5D scores were significantly correlated with physical activity over 4 METs on non-hemodialysis treatment days (r = 0.426, p = 0.003). In women, EQ-5D scores were also correlated with physical activity over 4 METs on hemodialysis treatment days and non-hemodialysis treatment days. By stepwise multiple regression analysis, physical activity over 4 METs on non-hemodialysis treatment days was a determinant factor of EQ-5D even after adjusting for age and K6 scores.

CONCLUSION

Physical activity over 4 METs on non-hemodialysis treatment days might be associated with EQ-5D in patients on chronic hemodialysis, especially in women.

Reduced level of physical activity in Japanese patients with chronic obstructive pulmonary disease

BACKGROUND

There is increasing interest in the quantification of physical activity (PA) with an accelerometer for the management of chronic obstructive pulmonary disease (COPD). However, a detailed understanding of the PA in Japanese patients with COPD is lacking. We evaluated the levels of PA in terms of intensity in Japanese patients with COPD and evaluated the factors, which could influence the PA.

METHODS

Forty-three outpatients with COPD and 21 age-matched healthy subjects were monitored with a triaxial accelerometer, and their PA was compared. Furthermore, the effects of pulmonary function, ADO index (age, dyspnea, and airflow obstruction) and modified BODE index (body mass index, airflow obstruction, dyspnea, and exercise capacity) on the PA were evaluated.

RESULTS

The PA in COPD was significantly reduced at all intensities. The reduced levels of PA in COPD were 23.1% at ≥2.0 metabolic equivalents (METs), 33.0% at ≥2.5 METs, 50.9% at ≥3.0 METs, and 66.9% at ≥3.5 METs, compared with that of healthy subjects, and the reduction was significant at GOLD stage III. The values of FVC, FEV1.0, and DLCO/VA were correlated with that of the PA, but the lung volume parameters were not. The ADO and modified BODE indices were also well correlated with the PA.

CONCLUSIONS

The reduced levels of PA in Japanese patients with COPD were objectively demonstrated in terms of intensity that could provide us a new target for the management of COPD.

Validation of the triaxial accelerometer for the evaluation of physical activity in Japanese patients with COPD

OBJECTIVE

The quantification of physical activity is useful for the management of chronic obstructive pulmonary disease (COPD) but has not been fully established yet. The DynaPort Activity Monitor(®) (DAM), a triaxial accelerometer is the only well validated accelerometer in Caucasians but it has not been validated in Japanese COPD patients. We initially evaluated the reproducibility of the DAM in Japanese healthy subjects. Next, the within-subject repeatability and the determinants of physical activity were investigated in Japanese COPD patients.

MATERIALS AND METHODS

The durations of locomotion, standing, and sitting measured by the DAM were compared to those of the self-records (Study 1). COPD patients wore the DAM for 3 days and the durations of each activity of 2 selected days were compared to assess the repeatability (Study 2). The relationship between the duration of locomotion and the physiological properties were examined (Study 3).

RESULTS

The activities measured by the DAM were significantly associated with those of the self-records (p<0.001). The values of the intra-class correlation coefficient (ICC) for the reproducibility were over 0.99, and the agreement with the self-records was observed for the DAM. Similarly, the values of ICC for repeatability were over 0.84 in all activities, and there was no systematic bias in the COPD patients. The duration of locomotion was negatively correlated with the total lung capacity (TLC) and closing capacity/TLC, but not with other pulmonary functions, exercise capacity, muscle force, dyspnea, or modified BODE index.

CONCLUSION

The triaxial accelerometer is reliable for evaluating the physical activity of Japanese COPD patients.