Coherence between self-reported and objectively measured physical activity in patients with chronic obstructive lung disease: a systematic review

Monitoring of physical activity using accelerometry in patients with chronic obstructive pulmonary disease

OBJECTIVES

The main objective of the study was to analyze the characteristics of physical activity in people with Chronic Obstructive Pulmonary Disease. Secondarily, the association between the number of steps per day and the baseline sociodemographic and clinical characteristics of the sample was evaluated.

METHODS

A multicenter longitudinal descriptive study was carried out in four Primary Care centers in Madrid. The participants were 80 people diagnosed with COPD. In a face-to-face interview, sociodemographic information and clinical characteristics were collected. Physical activity was measured over a week with a three-axis accelerometer that recorded wear time, number of steps per day, walking time, and time spent performing light, moderate, vigorous, and very vigorous physical activity.

RESULTS

The average time of use of the accelerometer was 6.84 ± 0.4 days. The number of daily steps taken was 6902.24 ± 3994.01 with a walking time of 78.07 ± 41.85 min/day. The time of light physical activity was 69.66 ± 46.42 min/day, of moderate activity 92.76 ± 42.91 min/day, of vigorous activity 9.93 ± 13.6 min/day and of very active activity vigorous 0.26 ± 0.64 min/day.

CONCLUSIONS

The participants mainly carried out physical activity of light and moderate intensity, complying with current recommendations, while the time dedicated to vigorous and very vigorous activities was reduced and was insufficient.

Physical activity among adults with chronic obstructive pulmonary disease in Spain (2014-2020): Temporal trends, sex differences, and associated factors

OBJECTIVES

To evaluate trends in the prevalence of physical activity (PA) from 2014 to 2020; to identify sex differences and sociodemographic and health-related factors associated with PA in individuals with chronic obstructive pulmonary disease (COPD); and to compare PA between individuals with and without COPD.

METHODS

Cross-sectional and case-control study.

SOURCE

European Health Interview Surveys for Spain (EHISS) conducted in 2014 and 2020. We included sociodemographic and health-related covariates. We compared individuals with and without COPD after matching for age and sex.

RESULTS

The number of adults with COPD was 1086 and 910 in EHISS2014 and EHISS2020, respectively. In this population, self-reported "Medium or high frequency of PA" remained stable (42.9% in 2014 and 43.5% in 2020; p = 0.779). However, the percentage who walked on two or more days per week rose significantly over time (63.4%-69.9%; p = 0.004). Men with COPD reported more PA than women with COPD in both surveys. After matching, significantly lower levels of PA were recorded in COPD patients than in adults without COPD. Multivariable logistic regression confirmed this trend in COPD patients and showed that male sex, younger age, higher educational level, very good/good self-perceived health, and absence of comorbidities, obesity, and smoking were associated with more frequent PA.

CONCLUSIONS

The temporal trend in PA among Spanish adults with COPD is favorable, although there is much room for improvement. Insufficient PA is more prevalent in these patients than in the general population. Sex differences were found, with significantly more frequent PA among males 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.

High 24-Hour Respiratory Symptoms and Low Physical Activity in the Stable COPD Romanian Cohort of SPACE Study

Objective

This study assessed the characteristics and the relationship between symptoms in any part of the 24-hour (24-h) day, physical activity level (PAL), and other clinical and functional outcomes in stable COPD patients.

Patients and Methods

Out of the 2162 patients enrolled in the SPACE study (The Symptoms and Physical Activity in COPD patients in Europe, clinicaltrials.gov NCT03031769), 406 (18.8%) were recruited from Romania. Here, we present the Romanian cohort results. Eligible patients were adults with age at least 40 years, confirmed diagnosis of stable COPD, current or former smokers with a smoking history of minimum 10 pack-years. The 24-h respiratory symptoms were assessed using Early Morning Symptoms of COPD Instrument (EMSCI), Evaluating Respiratory Symptoms in COPD (E-RS™: COPD) and Nighttime Symptoms of COPD Instrument (NiSCI). During clinical interview, patients self-evaluated PAL through Exercise as Vital Sign (EVS) and Yale Physical Activity Survey (YPAS). Physicians assessed PAL through their clinical judgment.

Results

For each combination of 2 between the early morning (EM), daytime (DT) and night-time (NT) symptoms of the 24-h day, there was a significant association (p < 0.001 for each). All symptoms significantly correlated with exacerbation history (p < 0.001 for EM and NT, p=0.002 for DT), and number of severe exacerbations (p < 0.001 for DT, p=0.001 for EM and p=0.026 for NT, respectively). The 24-h symptoms correlated negatively and significantly with PAL (p < 0.001), irrespective of the assessment used. Self-reported PAL negatively correlated with dyspnea, symptom burden, severity of disease and number of exacerbations (p < 0.001). Patients spent an average (standard deviation) of 25.8 (21.0) hours/week performing physical activity. Physicians overestimated their patients' daily PAL.

Conclusion

A negative and significant correlation between the 24-h day symptoms and PAL was identified in stable COPD patients. Physicians need to routinely assess PAL using adequate tools and start educating inactive COPD patients to optimize their disease outcomes.

Factors associated with physical activity among COPD patients with mild or moderate airflow obstruction

Physical inactivity is already present among patients with chronic obstructive pulmonary disease (COPD) of mild or moderate airflow obstruction. Most previous studies that reported on determinants of physical activity in COPD included patients with severe COPD. Therefore, the aim of this study was to explore which patient characteristics were related with physical activity in COPD patients with mild or moderate airflow obstruction. Cross-sectional analyses were performed on patients selected from the population-based Netherlands Epidemiology of Obesity study. Patients were included if they had a physician-diagnosed COPD GOLD 0-2 or had newly diagnosed COPD GOLD 1-2. Physical activity was evaluated using the Short Questionnaire to Assess Health-Enhancing Physical Activity (SQUASH) questionnaire and reported in hours per week of metabolic equivalents (MET-h/week). Associations between sociodemographic, lifestyle, clinical and functional characteristics were examined using regression analysis. 323 patients were included in research (77 with physician-diagnosed and 246 with newly diagnosed COPD). We found that physical activity was positively associated with pulmonary function: FEV1 (regression coefficient 0.40 (95% CI 0.09,0.71)) and FVC (regression coefficient 0.34 (95% CI 0.06,0.61)). Physical activity was associated with anxiety (regression coefficient =0.9 (95% CI 0.3,1.6)) only for physician-diagnosed patients. Lung function and anxiety level determine level of physical activity among COPD patients with mild or moderate airflow obstruction. Thus, integrating it into the physical activity plans could help to increase physical activity level of the patients.

Effect of health locus of control on physical activity in stable patients with chronic obstructive pulmonary diseases

[Purpose] A strong correlation exists between low physical activity and the prognosis of patients with chronic obstructive pulmonary disease (COPD). The interaction between psychological factors and low physical activity remains unclear in patients with COPD. Here, we investigated the impact of the health locus of control (HLOC) on the response to an education program in patients with COPD. [Participants and Methods] We assessed the physical activities and HLOC in participants with COPD before and after a five-month education program. We assessed physical activity using the Japanese version of the International Physical Activity Questionnaire (IPAQ). We evaluated the HLOC using the Japanese version of the HLOC scales. We provided an identical educational program to all participants after the initial evaluation. [Results] The total activity and walking scores were significantly elevated after the intervention. We observed a significant negative correlation between the IPAQ Total score after the intervention and the supernatural HLOC. We also observed significant negative correlations between the IPAQ Vigorous score after the intervention and Family HLOC and Chance HLOC. [Conclusion] The response of patients with COPD to self-care educational programs was influenced by the HLOC.

Evaluation of the Skeleton Avatar Technique for Assessment of Mobility and Balance Among Older Adults

Background: Mobility and balance is essential for older adults' well-being and independence and the ability to maintain physically active. Early identification of functional impairment may enable early risk-of-fall assessments and preventive measures. There is a need to find new solutions to assess functional ability in easy, efficient, and accurate ways, which can be clinically used frequently and repetitively. Therefore, we need to understand how functional tests and expert assessments (EAs) correlate with new techniques.

Objective: To explore whether the skeleton avatar technique (SAT) can predict the results of functional tests (FTs) of mobility and balance: Timed Up and Go (TUG), the 30-s chair stand test (30sCST), the 4-stage balance test (4SBT), and EA scoring of movement quality.

Methods: Fifty-four older adults (+65 years) were recruited through pensioners' associations. The test procedure contained three standardized FTs: TUG, 30sCST, and 4SBT. The test performances were recorded using a three-dimensional SAT camera. EA scoring was performed based on the video recordings of the 30sCST. Functional ability scores were aggregated from balance and mobility scores. Probability theory-based statistical analyses were used on the data to aggregate sets of individual variables into scores, with correlation analysis used to assess the dependency between variables and between scores. Machine learning techniques were used to assess the appropriateness of easily observable variables/scores as predictors of the other variables included.

Results: The results indicate that SAT data of the fourth 4SBT stage could be used to predict the aggregated results of all stages of 4SBT (with 7.82% mean absolute error), the results of the 30sCST (11.0%), the TUG test (8.03%), and the EA of the sit-to-stand movement (8.79%). There is a moderate (significant) correlation between the 30sCST and the 4SBT (0.31, p = 0.03), but not between the EA and the 30sCST.

Conclusion: SAT can predict the results of the 4SBT, the 30sCST (moderate accuracy), and the TUG test and might add important qualitative information to the assessment of movement performance in active older adults. SAT might in the future provide the means for a simple, easy, and accessible assessment of functional ability among older adults.

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.

Affect Improvements and Measurement Concordance Between a Subjective and an Accelerometric Estimate of Physical Activity

Abstract. Objectives: Physical activity (PA) positively influences several aspects of mental well-being including affect improvements. Yet, the fact that subjective and objective measures of PA often diverge challenges research on the relationship of PA and affect. Methods: Subjective (ecological momentary assessment, EMA) and objective (combined heart rate and accelerometric activity tracker) measures of PA alongside repeated ratings of positive and negative affects were obtained from 37 participants over 7 consecutive days. Results: Subjective and objective PA were significantly positively correlated. Affect improvements, that is, negative affect decrease as well as positive affect increase, were predicted by both subjective (EMA) and objective (activity tracker) data. Conclusions: Measurement concordance supports the validity of both assessment strategies. Affect improvements result from both subjective representations of one’s own activity as well as from physiological mechanisms of PA that one is not aware of, suggesting two independent routes to affect improvements.

Improvement In Self-Reported Physical Functioning With Tiotropium/Olodaterol In Central And Eastern European COPD Patients

Background

Reduced physical activity is associated with increased morbidity and mortality in patients with COPD. Studies suggest that treatment with the long-acting muscarinic antagonist tiotropium and the long-acting β₂-agonist olodaterol increases exercise capacity. This study assessed the effects of a fixed-dose combination (FDC) of tiotropium/olodaterol (delivered via Respimat^®) on physical functioning in patients with stable COPD in a “real-world setting”.

Methods

An international, open-label, single-arm, non-interventional study conducted in nine countries measuring changes in self-reported physical functioning in COPD patients treated with tiotropium/olodaterol 5/5 μg FDC for approximately 6 weeks. The primary endpoint was therapeutic success, defined as a minimum 10-point increase in the 10-question Physical Functioning Questionnaire (PF-10) score. Secondary endpoints included absolute change in PF-10 from Visit 1 to Visit 2, patient general condition (measured by Physician’s Global Evaluation score) and patient satisfaction with the treatment and device (assessed by Patient Satisfaction Questionnaire at the end of the study period).

Results

Therapeutic success was observed in 67.8% of 7218 patients (95% CI 66.7, 68.8) in the final analysis set after approximately 6 weeks of treatment with tiotropium/olodaterol. Mean change in PF-10 score between Visit 1 and Visit 2 was 16.6 points (95% CI 16.2, 17.0). Therapeutic success was 64.3% (95% CI 63.0–65.6%) in patients with infrequent (≤1) and 76.1% (95% CI 74.3–77.9%) in patients with frequent (≥2) exacerbations (p<0.0001). Patient general condition improved as indicated by an improvement in Physician’s Global Evaluation scores between visits. Most patients were very satisfied or satisfied with tiotropium/olodaterol treatment in general (81%), reported inhalation satisfaction (85%), and satisfactory handling of the device (84%). 1.3% of patients reported an investigator-defined drug-related adverse event.

Conclusion

Treatment with tiotropium/olodaterol led to an improvement in self-reported physical functioning in patients with COPD.

Multimodal Intervention to Improve Functional Status in Hypertensive Older Adults: A Pilot Randomized Controlled Trial

This pilot randomized controlled trial (RCT) was designed to provide the preliminary data necessary to conduct a full-scale trial to compare the efficacy of differing first-line antihypertensive medications in improving functional status in older adults, when combined with exercise. The primary objectives were to assess study feasibility, safety, and protocol integrity. Dependent outcomes included gait speed, exercise capacity, body composition, and systemic cardiometabolic biomarkers. Thirty-one physically inactive older adults (70.6 ± 6.1 years) with hypertension and functional limitations were randomly assigned to (1) Perindopril (8 mg/day n = 10), (2) Losartan (100 mg/day; n = 13), or (3) Hydrochlorothiazide (HCTZ: 25 mg/day; n = 8). Participants were also assigned to a 24-week multimodal exercise intervention, separated into an aerobic and concurrent (aerobic + resistance) phase to evaluate potential mode effects. Retention was 84% (26/31), and compliance was >90% and >79% with medication and exercise, respectively. A total of 29 adverse events (Perindopril = 5; Losartan = 12; HCTZ = 11) and one unrelated serious adverse event were observed throughout the trial. Overall, this pilot RCT provided critical data and identified several challenges to ultimately designing and implementing a fully powered trial.

The impact of pulmonary rehabilitation on severe physical inactivity in patients with chronic obstructive pulmonary disease: a pilot study

Introduction

In patients with COPD, severe physical inactivity (SPI, which is defined as total daily energy expenditure/resting energy expenditure; physical activity level [PAL] ratio, <1.4) is associated with increased morbidity and mortality. Pulmonary rehabilitation (PR) increases physical capacity in COPD, but the impact on SPI is unknown. In this study, we aimed at elucidating the prevalence of SPI in COPD patients attending standard PR, the impact of PR on SPI prevalence, and the relationship between SPI and time spent in moderate physical activity thus whether American College of Sports Medicine (ACSM) recommendations are clinically useful in excluding SPI in COPD.

Methods

This is a prospective non-interventional pilot study on patients with COPD completing PR, consenting to wear an accelerometer (Sensewear^© Armband) for a week before and after completing PR to assess changes in energy expenditure, time spent in physical activity, and number of daily steps. Low level of daily physical activity was not an inclusion criterion.

Results

In total, 57 patients completed the study and 31 (54%) had SPI at baseline. In patients with SPI, baseline median FEV₁ was 48 (range, 28–86) % of predicted and GOLD B, n=11 (35%)/GOLD D, n=20 (65%). Surprisingly, 31 of SPI patients (97%) spent ≥150 minutes/week in moderate physical activity. After rehabilitation, 24 (78%) did not change activity level and were persistently SPI. We observed no differences at baseline between patient responding (n=7) vs not responding (n=24) to PR. Responders increased number of daily steps and time spent in lighter but not moderate physical activity during rehabilitation.

Conclusion

In this pilot study, SPI was prevalent, and PR had limited impact. Contraintui-tively, most patients with SPI complied with general recommendations of weekly hours spent in moderate physical activity. Our study highlights that increasing time spent in light activity rather than improving time spent in moderate activity is important in COPD patients with chronic dyspnea.

[Follow-up and evaluation of plans developed during pulmonary rehabilitation]

BACKGROUND

Pulmonary rehabilitation inevitably contains two essential components: therapeutic education and exercise training. The principal aim of this study was to evaluate the evolution over a year of the realization of plans determined during a pulmonary rehabilitation program (PRP).

METHODS

At the end of a PRP the patient made plans in accordance with his health condition. A telephone enquiry was undertaken at 3, 7 and 12 months to evaluate the progress of the plans, the motivation to perform them, dyspnoea and quality of life.

RESULTS

The data of 65 patients were analyzed (87 inclusions). Fifty-seven percent of the plans continued for one year. Walking had an adherence rating of 71%. Loss of motivation appeared to be the main cause for stopping (20%). Quality of life remained stable (p=0.39) and an increase in dyspnoea, though statistically significant (p<0.01), was of no clinical relevance.

CONCLUSION

The majority of plans were maintained but without clinical effect on the quality of life or the level of dyspnoea. Decreased motivation was the major limitation to realization or continuation of the plans. New studies will have to be implemented to analyze the factors which lead to this decrease.

Self-reported task-oriented physical activity: A comparison with objective daily step count in COPD

BACKGROUND

Low physical activity (PA) is associated with adverse health outcomes independent of airflow limitation in COPD. Self-reported assessments are often limited to global estimates of PA and may not be directly translatable to patients' goals and motivations. We developed a task-oriented PA checklist and examined its performance relative to pedometer-assessed daily step count in two COPD cohorts.

METHODS

Task-oriented daily physical activity (DPA) was assessed in two COPD cohorts using either interviewer-administered recall questionnaire (DPA-R, Cohort 1, n = 109) or a self-administered diary-format daily checklist (DPA-C, Cohort 2, n = 175). Daily step count was measured in both cohorts using the Omron HJ-720 ITC pedometer. Univariate associations between individual DPA items and [a] cross-sectional and [b] longitudinal change (Cohort 1) in daily step count were assessed using a Pearson's correlation. Composite scores comprised of individual DPA items with univariate association p-values <0.1 were tested for association with daily step count using multivariate models.

RESULTS

Tasks associated with average daily step count in both cohorts included putting on shoes, showering, washing hair, walking for exercise, the frequency of walks >10 min, and walking on an incline (Pearson's rho range = 0.14-0.43). A composite score of these 6 DPA items demonstrated significant associations with baseline average daily step count in both cohorts (ρ = 0.5 & 0.47, Cohorts 1 & 2, respectively) and longitudinal change in daily step count (ρ = 0.46, Cohort 1).

CONCLUSIONS

Self-reported task-oriented assessments complement direct monitoring and have potential clinical utility in exercise counseling to increase PA among COPD patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01772082.

Physical activity in the morning and afternoon is lower in patients with chronic obstructive pulmonary disease with morning symptoms

Background

Patients with chronic obstructive pulmonary disease (COPD) experience symptoms that vary over the day. Symptoms at the start of the day might influence physical activity during the rest of the day. Therefore, physical activity during the course of the day was studied in patients with low and high morning symptom scores.

Methods

This cross-sectional observational study included patients with moderate to very severe COPD. Morning symptoms were evaluated with the PRO-morning COPD Symptoms Questionnaire (range 0–60); the median score was used to create two groups (low and high morning symptom scores). Physical activity was examined with an accelerometer. Activity parameters during the night, morning, afternoon and evening were compared between patients with low and high morning symptom scores using independent t-tests or Mann-Whitney U tests.

Results

Seventy nine patients were included. Patients were aged (mean ± SD) 65.6 ± 8.8 years with a mean forced expiratory volume in 1 s of 55 ± 17%predicted. Patients with low morning symptom scores (score < 17.0) took more steps in the afternoon (p = 0.015) and morning (p = 0.030). There were no significant differences during the evening and night.

Conclusion

Patients with high morning symptom scores took significantly fewer steps in the morning and afternoon than those with low morning symptom scores. Prospective studies are needed to prove causality between morning symptoms and physical activity during different parts of the day.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0749-4) contains supplementary material, which is available to authorized users.

The association between objectively measured physical activity and morning symptoms in COPD

PURPOSE

The morning is the most bothersome period for COPD patients. Morning symptom severities in different Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages are not well studied. Furthermore, factors that are associated with morning symptoms, especially the associations with objectively measured physical activity, are also not well described.

MATERIALS AND METHODS

The aim of this cross-sectional observational study was to assess morning symptom severity in GOLD A, B, C and D patients, according to the definitions of the GOLD 2015 statement. Morning symptoms were assessed with the PRO-Morning COPD Symptoms Questionnaire. Differences in morning symptom severity between different COPD stages were assessed with a one-way analysis of variance followed by post hoc analyses. The association between dyspnea severity (assessed with the modified Medical Research Council scale), health status, airflow limitation, lung hyperinflation, anxiety and depression, inflammatory parameters, exacerbations, objectively measured physical activity parameters retrieved from accelerometry and morning symptom severity was evaluated using linear regression analysis.

RESULTS

Eighty patients were included (aged 65.6±8.7 years, forced expiratory volume in 1 second [FEV₁] % predicted 55.1±16.9). Mean (±SD) morning symptom score was 19.7 (±11.7). Morning symptom severity was significantly different between COPD stages: mean (±SD) score in GOLD A was 9.7 (±7.2), in GOLD B 19.8 (±10.7), in GOLD C 8.6 (±9.3) and in GOLD D 23.8 (±11.2) (p<0.001). Lower health status, more symptoms, increased anxiety and depression, less physical activity (all p<0.001) and lower FEV₁ (p=0.03) were associated with an increased morning symptom severity.

CONCLUSION

Patients with overall more symptomatic COPD have significant higher morning symptom scores. Morning symptom severity was associated with important clinical outcomes: lower health status, more symptoms, increased anxiety and depression, fewer steps a day, less time in moderate and vigorous physical activity with bouts of at least 10 minutes and lower FEV₁. The data suggest that morning symptoms should be carefully assessed in addition to assessment by general COPD-specific questionnaires, especially in those with more symptomatic COPD. More research is needed on potential therapies to improve morning symptoms; this study shows potential targets for intervention.

Self-reported daily walking time in COPD: relationship with relevant clinical and functional characteristics

Background

Quantifying physical activity in chronic obstructive pulmonary disease (COPD) is important as physical inactivity is related to poor health outcomes. This study analyzed the relationship between patients’ self-reported daily walking time and relevant characteristics related to COPD severity.

Methods

Pooled analysis was performed on data from four observational studies on which daily walking time was gathered from a personal interview. Patients were classified as physically inactive if walking time was <30 min/day. Walking times were described and compared according to several markers of disease severity.

Results

The mean daily walking time of 5,969 patients was 66 (standard deviation [SD] 47) min/day; 893 (15%) patients were inactive. A linear dose–response relationship was observed between walking time and the modified Medical Research Council (mMRC) dyspnea score, admissions, COPD assessment test (CAT), body mass index, airway obstruction, dyspnea, exacerbation (BODEx) index, and Charlson index (P<0.001). Daily walking times were lower in patients classified as Global Initiative for Chronic Obstructive Lung Disease (GOLD) B and D (P<0.001). Often, inactive patients had mMRC or Charlson index >3, post-bronchodilator forced expiratory volume in the first second <30% predicted, at least one hospitalization for COPD, classified as GOLD B or D, BODEx >4, and CAT score >30.

Conclusion

Lower self-reported walking times are related to worse markers of disease severity in COPD.

Accelerometer- versus questionnaire-based assessment of physical activity and their changes over time in patients with COPD

Background and objective

Physical activity (PA) is an important outcome parameter in patients with COPD regarding hospitalizations and mortality. Both objective assessment by accelerometers and self-evaluation by questionnaires were used in studies investigating PA in COPD. Whether self-reported questionnaires can adequately reflect PA and its changes over time compared to objective assessments has not been thoroughly investigated in COPD. In this COPD cohort study, we evaluated whether PA measured by accelerometer and its annual changes can also be assessed by self-reported questionnaires.

Methods

In 178 COPD patients with at least two assessments of PA, the agreement between objectively measured and self-reported activity was analyzed by Bland–Altman plots. Daily PA was assessed by a triaxial activity monitor over 1 week and by the self-reported German PA questionnaire 50+.

Results

Comparison between the two methods of measurement revealed no convincing agreement with a mean difference and limits of agreement (±1.96 standard deviation [SD]) of time spent in at least moderate PA (>3 metabolic equivalent of task [MET]) of −77.6 (−340.3/185.2) min/day, indicating a self-reported overestimation of PA by the questionnaire. The mean difference and limits of agreement (±1.96SD) in the annual change of PA was 1.2 min/day (−208.2/282.6 min/day), showing also a poor agreement on an individual level.

Conclusion

Evaluation of objectively measured and self-reported PA and their annual changes revealed no agreement in patients with COPD. Therefore, the evaluated questionnaire seems not helpful for measurement of PA and its changes over time.