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edicine and Rehabilitation
Archives of Physical M journal homepage: www.archives-pmr.orgArchives of Physical Medicine and Rehabilitation 2013;94:2396-402
ORIGINAL ARTICLE
Physical and Psychosocial Factors Associated WithPhysical Activity in Patients With Chronic ObstructivePulmonary Disease
Jorine E. Hartman, PhD,a,b H. Marike Boezen, PhD,b,c Mathieu H. de Greef, PhD,dNick H. ten Hacken, MD, PhDa,b
From the aDepartment of Pulmonary Diseases, University of Groningen, University Medical Center Groningen, Groningen; bUniversity ofGroningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, Groningen; cDepartment of Epidemiology,University of Groningen, University Medical Center Groningen, Groningen; dDepartment of Human Movement Sciences, University of Groningen,University Medical Center Groningen, Groningen, The Netherlands.
Abstract
Objectives: To assess physical activity and sitting time in patients with chronic obstructive pulmonary disease (COPD) and to investigate which
physical and psychosocial factors are associated with physical activity and sitting time.
Design: Cross-sectional study.
Setting: Patients were recruited at outpatient clinics of general hospitals and from general practitioners.
Participants: Patients (NZ113) with mild to very severe COPD.
Interventions: Not applicable.
Main Outcome Measures: Physical activity and sitting time were measured with a triaxial accelerometer (24h/d).
Results: Mean locomotion time per 24 hours was 6.8% (range, 0.7%e20.4%). Elevated physical activity was independently associated with higher
self-efficacy, higher functional exercise capacity, and lower lung hyperinflation. Decreased physical activity was strongest in more severe stages of
COPD, in which the patients were mainly limited by physical disease-specific factors (higher lung hyperinflation, worse dyspnea severity, worse leg
muscle function, and oxygen use). In less severe patients, physical activity was independently associated with more generic factors (higher self-efficacy
and the spring/summer season). Sitting time did not differ between severity stages, and longer sitting time in the total group was independently
associated with more positive perception of treatment control, less autonomous motivation to exercise, not using sleep medication, and oxygen use.
Conclusions: Both physical and psychosocial factors were associated with physical activity in patients with COPD. The factors associated with
physical activity differed between disease severity stages, raising the question of whether physical activity enhancement programs should differ as
well. Sitting time should be investigated further.
Archives of Physical Medicine and Rehabilitation 2013;94:2396-402
ª 2013 by the American Congress of Rehabilitation Medicine
Physical inactivity has been shown to be a predictor of mortality inpatients with chronic obstructive pulmonary disease (COPD).1
Unfortunately, many patients with COPD have sedentary life-styles.2 Physical activity is a modifiable factor and hence aninteresting potential treatment goal in COPD. Increasing physical
Presented to the University of Groningen, University Medical Center Groningen, Groningen
Research Institute for Asthma and COPD, Groningen, The Netherlands.
Supported by the Dutch Asthma Foundation (grant no. 3.4.07.036) and an unrestricted grant
from Boehringer Ingelheim, Alkmaar, The Netherlands (grant no. S10406).
Both study sponsors were not involved in the study.
Clinical Trial Register No. (Dutch Trial Register): NTR1497.
No commercial party having a direct financial interest in the results of the research supporting this
article has conferred orwill confer a benefit on the authors or on any organizationwithwhich the authors
are associated.
0003-9993/13/$36 - see front matter ª 2013 by the American Congress of Re
http://dx.doi.org/10.1016/j.apmr.2013.06.029
activity has been shown to decrease dyspnea severity and improvemuscle function and quality of life.3 Therefore, physical activitymay break the vicious circle of dyspnea-induced immobility andsubsequent deconditioning.4 The variation in physical activitybetween patients with COPD is high2; and to be able to reducephysical inactivity, it would be useful to explore the factors thatare associated with physical activity.
In the last decade, knowledge on the factors associated withphysical activity in patients with COPD has increased signifi-cantly. However, many studies underlying our knowledge hadsmall sample sizes or specific COPD populations, contributing todiscrepant findings.5 Furthermore, mainly COPD-specific physical
habilitation Medicine
Physical activity in chronic obstructive pulmonary disease 2397
factors have been investigated. For example, significant associa-tions were found between physical activity and lung function, lunghyperinflation, dyspnea severity, exercise capacity, muscle func-tion, use of long-term oxygen therapy (LTOT), and comorbid-ities.5-7 However, those physical factors only incompletely reflectthe physical activity level because psychosocial factors mostlikely affect physical activity as well. Unfortunately, psychosocialfactors are less frequently investigated in COPD. Potentialpsychosocial factors could be social support, motivation to bephysically active, illness perception, self-efficacy, and sleepquality. The few studies available in the literature found a signifi-cant association between physical activity and self-efficacy inphysical activity and no association with depression.5
Most studies on COPD have investigated physical activity andnot sedentary behavior, such as sitting time. Sedentary time hasbeen shown to be an independent risk factor for several healthoutcomes, such as cardiovascular diseases, independent of phys-ical activity,8,9 and could also be an important potential treat-ment target.
We hypothesize that both physical and psychosocial factors areassociated with physical activity and sitting time in patients withCOPD. Furthermore, we hypothesize that these factors coulddiffer between patients with different severities of COPD. Theaims of this study are to assess (1) the level and variation ofphysical activity and sitting time in patients with COPD and (2)the independent factors associated with physical activity andsitting time, including physical and psychosocial variables.
Methods
Participants
Patients with mild to very severe COPD were recruited at outpa-tient clinics of general hospitals and from general practitioners inthe northern part of The Netherlands. Patients were enrolled in thiscross-sectional study between February 2009 and February 2012.Patients were included if they had a COPD diagnosis according tothe Global Initiative for Chronic Obstructive Lung Disease(GOLD).10 Patients were excluded if they had a serious activedisease that needed medical treatment (eg, recent myocardialinfarction) or treatment for a COPD exacerbation in the past 2months. The study was approved by the ethics committee of theUniversity Medical Center Groningen, and all patients providedinformed consent.
Potential factors associated with physical activity
We have searched the literature to identify potential factorsassociated with physical activity or sitting time in patients with
List of abbreviations:
BMI body mass index
COPD chronic obstructive pulmonary disease
FEV1 forced expiratory volume in 1 second
GOLD Global Initiative for Chronic Obstructive Lung Disease
IPQ-R Illness Perception Questionnaire-revised
LTOT long-term oxygen therapy
RV residual volume
6MWD 6-minute walk distance
SRQ-E Exercise Self-Regulation Questionnaire
www.archives-pmr.org
COPD. Physical activity could be associated with generic andCOPD-specific factors. The factors that were shown to be asso-ciated with physical activity in patients with COPD have beenpreviously described. In general adult populations, beinga woman, being older, having higher body weight, having lowereducation, having health problems, having lower self-efficacy, andpoor weather conditions were shown to be associated with lowerphysical activity.11-13 Furthermore, there is some evidence thatsocial support, motivation to exercise, depression, and sleepquality were associated with physical activity.14-16
Measurements
Physical activity was measured with a triaxial accelerometer(DynaPort),a which has shown to be an accurate instrument forevaluating physical activity in patients with COPD.17 The deviceis worn around the waist at the lower back, and patients wereinstructed to wear it day and night, for 1 week, except duringshowering and swimming.
Biographic factors
Data on medication use, LTOT, number of exacerbations in the pastyear, smoking status, living situation, and education level werereported. These data were self-reported and, if possible, verified inmedical records. Seasons were split in 2: spring and summer(AprileSeptember) and autumn and winter (OctobereMarch).During the study period (February 2009eFebruary 2012), the meantemperature during spring and summer was 15.1�C (range, 4.7e27.6�C) and 5.9�C (range, 0.7e14.7�C) during autumn and winter(data were obtained from the Royal Netherlands MeteorologicalInstitute, www.knmi.nl). Comorbidity was assessed by the Cumu-lative Illness Rating Scale for Geriatrics.18
Physical factors
Pulmonary functionForced expiratory volume in 1 second (FEV1) and forced vitalcapacity were measured using a spirometer (Masterscreenpulmonary function testing system; Viasys)b; residual volume(RV), total lung capacity, and intrathoracic gas volume weremeasured by body plethysmograpy (MasterScreen boydple-thysmography).b Both methods were according to EuropeanRespiratory Society/American Thoracic Society guidelines.19,20
Dyspnea severityDyspnea severity was registered by the modified MedicalResearch Council dyspnea index.21
Exercise capacityMaximal exercise capacity was measured by an incremental cycleergometer test (bicycle ergometer: Jaeger ER 900Lc; Oxycon Pro,CareFusionb) in line with the American Thoracic Society/Amer-ican College of Chest Physicians statement.22 Functional exercisecapacity was measured by a 6-minute walk distance (6MWD) testaccording to the American Thoracic Society guidelines.23
Leg muscle functionLeg muscle function was measured by a 30-second chair standtest.24 This test involves counting the number of times, within 30
2398 J.E. Hartman et al
seconds, that the patient can come to a full stand without using thearms from a seated position.
Body compositionFat-free mass was measured by bioelectrical impedance (Bodystat1500d) and calculated with COPD- and sex-specific equations.25
Body mass index (BMI) was also calculated.
BODE IndexThe BODE Index is a multidimensional index combining BMI,FEV1, modified Medical Research Council dyspnea index, andthe 6MWD.26
Psychosocial factors
Social support on physical activity was measured by the Dutchversion of the Social Support for Exercise Behaviors ScaleQuestionnaire.27 Motivation to exercise was measured by theExercise Self-Regulation Questionnaire (SRQ-E).28 Depressionwas measured by the Beck Depression Inventory.29 Illnessperception was measured by the Illness Perception Questionnaire-revised (IPQ-R).30 Self-efficacy was measured by the Dutchversion of the Perceived Physical Ability Subscale Question-naire.31 Sleep quality was measured by the Pittsburgh SleepQuality Index.32
Quality of life
Quality of life was measured by a disease-specific questionnaire,the St. George’s Respiratory Questionnaire,33 and by a genericquestionnaire, the RAND 36-Item Short-Form Health Survey.34
Health status was measured by the Clinical COPDQuestionnaire.35
Information on reliability and validity for all tests is listed insupplemental appendix S1 (available online only at http://www.archives-pmr.org/).
Study design
All measurements were performed during 3 study visits withinapproximately 6 weeks. The physical measurements were per-formed during different visits; therefore, these measurementswould not influence each other.
Statistical analyses
The sample size calculation is shown in supplemental appendix S2(available online only at http://www.archives-pmr.org/). Patientswere included in the analyses if they had worn the accelerometer forat least 4 full days, in accordance with the literature.36 A day wasconsidered a valid measurement day if the device was worn for atleast 94% of the day.37 The DynaPort is able to detect if the deviceis not being worn. When patients did not wear the accelerometerduring the night, this time during the night was recorded as lying.Physical activity outcomes were compared between GOLD stagesand BODE Index quartiles (based on the study population) usinganalysis of variance or Kruskal-Wallis tests with Holm-Bonferroniadjustment. Nonparametric tests were performed in case of non-normally distributed data. Locomotion time was calculated by thesum of percentage walking and percentage shuffling during 24hours and was analyzed as the outcome parameter for physical
activity and percentage sitting during 24 hours for sitting time.Shuffling was defined as all movement from a period of standing toanother period of standing that could not be classified as walkingbecause of lower intensity or because the number of steps was <3.Pearson or Spearman correlation coefficients were calculated to testunivariate associations between potential factors and locomotion orsitting time and between quality of life and physical activity.Differences between groups were tested using an independentsample t test or a Mann-Whitney U test. Stepwise backward linearregression analysis was performed to identify the factors inde-pendently associated with locomotion or sitting time, with adjust-ment for age, sex, and height. Variables were selected into thestepwise backward model if the P value was <0.2 in the univariateanalysis. Supplemental tables S1 and S2 (available online only athttp://www.archives-pmr.org/) show the results of the univariatetests and variables that were included in the regression analyses.The linear regression analysis assumptions were checked andconsidered valid if the residuals were normally distributed. P<.05was considered statistically significant. Statistical analyses wereperformed using PASW Statistics 18.e
Results
In this cross-sectional study, 115 patients with COPD wereincluded. The 113 patients who wore the accelerometer for at least4 full days were included in the analyses. Patient characteristicsare shown in table 1. None of the patients participated ina pulmonary rehabilitation program during the study or during 6months before study participation.
Figure 1 shows the physical activity variables per GOLD stageand BODE quartile. Locomotion time and steps per day did notdiffer between GOLD stages I and II; all other GOLD stagessignificantly differed, with lower physical activity in patients withmore severe COPD (supplemental table S3, available online onlyat http://www.archives-pmr.org/). All BODE quartiles signifi-cantly differed in locomotion time, and only BODE quartiles I andII did not differ in steps per day (supplemental table S4, availableonline only at http://www.archives-pmr.org/). Furthermore, theranges in physical activity outcomes were large within GOLDstages or BODE quartiles. Sitting time per day was not signifi-cantly different between GOLD stages or BODE quartiles.
Factors associated with physical activity (locomotiontime over 24h)
Measurement results of potential physical and psychosocialfactors per GOLD stage are shown in supplemental table S5(available online only at http://www.archives-pmr.org/).
Total groupHigher physical activity was significantly associated with higherfunctional and maximal exercise capacity, less airway obstruction,static lung hyperinflation and dyspnea severity, better leg musclefunction, lower number of exacerbations, better illness perceptionscores, lower depression scores, higher self-efficacy, and moreautonomous motivation to exercise. Physical activity was signifi-cantly lower in LTOT users and during autumn/winter (seesupplemental table S2, available online only at http://www.archives-pmr.org/).
Higher self-efficacy, higher 6MWD, and lower RV wereindependently associated with higher physical activity (table 2).
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Table 1 Patient characteristics (NZ113)
Characteristic Value
Sex, female 37 (32.7)
Age, y 65.0�8.7
Smoke status, current 30 (26.5)
Work status, working 12 (10.6)
Living situation, alone 30 (26.5)
LTOT, user 14 (12.4)
Season measured, spring or summer 55 (48.7)
Education level
Low 69 (61.1)
Middle 27 (23.9)
High 17 (15.0)
GOLD stage
I 30 (26.5)
II 30 (26.5)
III 32 (28.3)
IV 21 (18.6)
FEV1, % predicted 52 (14e119)
Steps per day 5552 (236e18,433)
Walking and shuffling time
% per 24h 6.8�3.5
min per 24h 97.9�50.4
Sitting time
% per 24h 37.3�8.4
min per 24h 537.1�121.0
NOTE. Data are presented as n (%), mean � SD, or median (range).
Physical activity in chronic obstructive pulmonary disease 2399
Mild-to-moderate COPD (GOLD stages I and II)Higher physical activity was significantly associated with higher6MWD and physical activity was significantly lower in autumn/winter (see supplemental table S1, available online only at http://www.archives-pmr.org/).
Higher self-efficacy and physical activity measured in spring/summer were independently associated with higher physicalactivity (see table 2).
(Very) severe COPD (GOLD stages III and IV)Higher physical activity was significantly associated with higherfunctional and maximal exercise capacity, less airway obstruction,static lung hyperinflation and dyspnea severity, better leg musclefunction, better subscale score consequences (IPQ-R), and lowerdepression scores. Additionally, physical activity was significantlylower in LTOT users (see supplemental table S2, available onlineonly at http://www.archives-pmr.org/).
Lower RV, less dyspnea severity, better leg muscle function,and not using LTOT were independently associated with higherphysical activity (see table 2).
Quality of life and health status
Physical activity was significantly associated with all subscalesand total scores of the St. George’s Respiratory Questionnaire andthe Clinical COPD Questionnaire (supplemental table S6, avail-able online only at http://www.archives-pmr.org/). All subscales ofthe RAND-36 Item Short-Form Health Survey, except thesubscales for mental health and bodily pain, were significantlyassociated with physical activity.
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Factors associated with sitting time
Total groupLonger sitting time was significantly associated with a highernumber of exacerbations in the past year, lower functional exer-cise capacity, and less autonomous motivation for exercise. Sittingtime was significantly higher in LTOT users, in patients who donot use sleep medication, and in patients living together withothers (see supplemental table S2, available online only at http://www.archives-pmr.org/).
A more positive perception of treatment control (IPQ-R),higher introjected regulation in exercise (taking on another’svalues, SRQ-E), not using sleep medication, and use of LTOTwere independently associated with longer sitting time (table 3).
Mild-to-moderate COPD (GOLD stages I and II)Longer sitting time was significantly associated with higher fat-free mass and a more positive perception of treatment control(IPQ-R).
Higher introjected regulation and a higher number of exacer-bations in the past year were independently associated with sittingtime (see table 3).
(Very) severe COPD (GOLD stages III and IV)Longer sitting time was significantly associated with externalregulation in exercise (no choice, others make me do it, SRQ-E)and was significantly higher in LTOT users.
Using LTOT was independently associated with longer sittingtime (see table 3).
Discussion
We assessed the level of both physical activity and sitting time inpatients with COPD with a broad range of disease severity.Furthermore, in addition to physical factors, we investigatedwhether psychosocial factors were also associated with physicalactivity or sitting time.
The largest difference in physical activity was present betweenpatients with GOLD stages II and III. This is in line with 2 studiesthat demonstrated a comparable numbers of steps per day in theGOLD stages.37,38 Furthermore, we found a high variation inphysical activity within the GOLD stages, which confirms that theseverity of airway obstruction alone does not explain the variation inphysical activity. The BODE Index (containing lung function andexercise capacity, dyspnea, and BMI) was slightly more stronglycorrelated with physical activity; however, the variation was stillhigh within quartiles, confirming that other factors also play a role.
Self-efficacy in physical ability, static lung hyperinflation, andfunctional exercise capacity were independently associated withphysical activity. In line with this, 2 studies found a positiveassociation between self-efficacy and physical activity.39,40 Self-efficacy has shown to be a strong predictor of exercise adher-ence14,41 and might, therefore, be an interesting treatment targetfor physical activity enhancement programs.
RV, contrary to FEV1, was independently associated withphysical activity. This is in line with the finding that lung hyper-inflation is more closely associated with patient-centeredoutcomes than FEV1.
42 Interestingly, cycle ergometry outcomesin this study were not independently associated with physicalactivity, as in the 6MWD. This supports the suggestion that the6MWD gives a better reflection of the physical conditions needed
Fig 1 Distribution of the types of activity and steps per GOLD stage or BODE Index quartile: distribution types of activity, mean percentage
relative time per 24 hour per GOLD stage (A); distribution types of activity, mean percentage relative time per 24 hour per BODE Index quartile (B);
steps per day per GOLD stage (C); and steps per day per BODE Index quartile (D). Abbreviations: BODE quartile 1, BODE score 0; BODE quartile 2, BODE
scores 1 and 2; BODE quartile 3, BODE scores 3 and 4; BODE quartile 4, BODE scores 5 through 8. *Significant difference between groups, P<.05.
2400 J.E. Hartman et al
to perform physical activity than a cycle ergometer test. Anotherstudy also found that 6MWD and lung hyperinflation were inde-pendently associated with physical activity, whereas cycle ergo-metry outcomes were not.6
The factors associated with physical activity differed betweenGOLD stages. In patients with mild-to-moderate COPD, self-efficacy and season were independently associated. Most likely,patients with COPD in an early stage were less restricted by theirdisease and more influenced by general factors. Furthermore, theinfluence of weather on physical activity should be reduced, forexample by discussing back-up activities in case of bad weather.Perhaps COPD-specific physical activity enhancement is notnecessary in the early disease stages; however, to prevent physicalinactivity in later stages, sedentary lifestyles should be addressed.
In patients with (very) severe COPD, higher RV, higher dyspneaseverity, worse leg muscle function, and LTOT use were inde-pendently associated with lower physical activity. Apparently,disease symptoms are the main limiting factor for physical activityin patients with more severe COPD.
A number of variables that we expected to be associated withphysical activity were not (eg, social support, sleep quality,comorbidity). Social support has been shown to improve exercisebehavior.43 In our study, patients with COPD reported low socialsupport scores and might, therefore, hardly experience socialsupport in that area. Involving significant others in the enhance-ment of physical activity could be important. Poor sleep qualitycould lead to fatigue during the day and, consequently, lowerphysical activity. However, although 29% of our patients were
www.archives-pmr.org
Table 2 Stepwise backward linear regression analyses with
percentage locomotion as the dependent variable
Variable B � SE P
Total population (R2Z.56)
Self-efficacy (LIVAS score) .096 � .034 .006
6MWD (m) .015 � .003 <.001
RV (L) �.612 � .200 .003
GOLD stages I and II (R2Z.25)
Self-efficacy (LIVAS score) 0.161 � .051 .003
Season (0Zspring/summer) �1.895 � .745 .014
GOLD stages III and IV (R2Z.66)
RV (L) �0.538 � .170 .003
Dyspnea (mMRC score) �0.763 � .273 .008
Chair stand test (no.) 0.414 � .097 <.001
LTOT (0Zno) �1.529 � .558 .009
NOTE. Analyses were adjusted for age, sex, and height.
Abbreviations: LIVAS, Dutch version of the Perceived Physical Ability
Subscale Questionnaire; mMRC, modified Medical Research Council
dyspnea index.
Physical activity in chronic obstructive pulmonary disease 2401
identified as poor sleepers (assessed by Pittsburgh Sleep QualityIndex score >532), we found no association between sleep qualityand physical activity. Contrary to other studies, we found noassociation between comorbidity and physical activity. Anexplanation could be that other studies used specific diseasegroups and not a composite index score, which is what we used. Inour sample, the numbers of patients in specific disease groupswere too small to analyze separately.
Unexpectedly, sitting time during the day did not differsignificantly between GOLD stages. However, patients with (very)severe COPD sat approximately 40 minutes per day longer thanpatients with mild-to-moderate COPD. This could be clinicallyrelevant because longer sitting time has been found to be associ-ated with an increased risk of mortality, even independent ofleisure time physical activity.44 Promoting breaks in sitting timecould be beneficial because it has been shown that a highernumber of interruptions in sedentary time, independent of totalsedentary time, was beneficially associated with metabolic riskvariables.8,45 This indicates that in addition to promoting physicalactivity, it could also be important to reduce sedentary behavior,for example by promoting breaks in sitting time. Despite what weexpected, use of sleep medication was associated with shortersitting time. However, the patients who used sleep medications
Table 3 Stepwise backward linear regression analyses with
percentage sitting as the dependent variable
Variable B � SE P
Total population (R2Z.26)
LTOT (0Zno) 8.143 � 2.360 .001
Treatment control (IPQ-R score) 0.627 � 0.239 .010
Introjected regulation (SRQ-E score) 1.381 � 0.560 .015
Use sleep medication (0Zno) �4.511 � 2.264 .049
GOLD stages I and II (R2Z.23)
Introjected regulation (SRQ-E score) 1.722 � 0.792 .035
No. of exacerbations 3.312 � 1.476 .030
GOLD stages III and IV (R2Z.16)
LTOT (0Zno) 8.449 � 3.120 .009
NOTE. Analyses were adjusted for age, sex, and height.
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also had a higher lying time compared with the patients who didnot use sleep medication. Apparently, this subset of patients mightlie down rather than sit down during the day when feeling tired.
Study limitations
Our sample size was relatively small; however, a strength of thestudy is that we investigated patients with all severity stages usingan extensive list of both physical and psychosocial measurements.Furthermore, our study lacked a control group, and it would beinteresting to investigate if factors associated with physical activitydiffer between healthy subjects and patients with COPD. Becauseof the cross-sectional design, we are not able to draw definiteconclusions regarding possible cause-effect relations; therefore,longitudinal studies are needed. We have performed backwardregression analyses, which have a limitation that the selection ofvariables is based on automated statistical criteria. Because of thelarge number of potential factors based on the literature, we choseto use this method to explore the factors associated with physicalactivity. Another strength was measuring physical activity witha well-validated accelerometer.17 However, this device is not ableto measure nonambulatory activities, such as cycling. This mayhave led to underestimation of physical activity.
Conclusions
This study showed that both physical and psychosocial factors areassociated with physical activity in patients with COPD.Decreased physical activity was strongest in more severe stages ofthe disease, in which the patients were mainly limited by physicaldisease-specific factors. In patients with less severe COPD,physical activity was associated with more generic and lessCOPD-specific factors. Remarkably, sitting time did not differbetween GOLD stages. Because sitting time or physical inactivityhas not been thoroughly investigated in patients with COPD, webelieve that future studies on physical activity should investigatethis aspect as well.
Suppliers
a. McRoberts, Raamweg 43, 2596 HN The Hague, TheNetherlands.
b. CareFusion Corp, 3750 Torrey View Court, San Diego,CA 92130.
c. Erich Jaeger GmbH, Leibnizstr 7, D-97204, Hoechberg,Germany.
d. Bodystat Ltd, PO Box 50, Douglas, Isle of Man, IM99 1DQ,UK.
e. SPSS Inc, 233 S Wacker Dr, 11th Fl, Chicago, IL 60606-6307.
Keywords
Lung; Motor activity; Pulmonary disease, chronic obstructive;Rehabilitation; Sedentary lifestyle; Self efficacy
Corresponding author
Nick H.T. ten Hacken, MD, PhD, Department of PulmonaryDiseases AA11, University Medical Center Groningen, PO
2402 J.E. Hartman et al
Box 30001, 9700 RB Groningen, The Netherlands. E-mailaddress: [email protected].
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tive pulmonary disease. N Engl J Med 2004;350:1005-12.
27. Stevens M, Bakker van Dijk A, de Greef MH, Lemmink KA,
Rispens P. A Dutch version of the Social Support For Exercise
Behaviors Scale. Percept Mot Skills 2000;90:771-4.
28. Ryan RM, Deci EL. Self-determination theory and the facilitation of
intrinsic motivation, social development, and well-being. Am Psychol
2000;55:68-78.
29. Beck AT, Ward CH, Mendelson M, Mock J, Erbaugh J. An inventory
for measuring depression. Arch Gen Psychiatry 1961;4:561-71.
30. Moss-Morris R, Weinman J, Petrie KJ, Horne R, Cameron LD,
Buick D. The revised Illness Perception Questionnaire (IPQ-R). Psy-
chol Health 2002;17:1-16.
31. Bosscher RJ, Laurijssen L, de Boer E. Measuring physical self-
efficacy in old age. Percept Mot Skills 1993;77:470.
32. Buysse DJ, Reynolds CF III, Monk TH, Berman SR, Kupfer DJ. The
Pittsburgh Sleep Quality Index: a new instrument for psychiatric
practice and research. Psychiatry Res 1989;28:193-213.
33. Jones PW, Quirk FH, Baveystock CM. The St George’s Respiratory
Questionnaire. Respir Med 1991;85(Suppl B):25-31; discussion
33-7.
34. Aaronson NK, Muller M, Cohen PD, et al. Translation, validation, and
norming of the Dutch language version of the SF-36 Health Survey in
community and chronic disease populations. J Clin Epidemiol 1998;
51:1055-68.
35. van der Molen T, Willemse BW, Schokker S, ten Hacken NH,
Postma DS, Juniper EF. Development, validity and responsiveness of
the Clinical COPD Questionnaire. Health Qual Life Outcomes 2003;1:
13.
36. Trost SG, McIver KL, Pate RR. Conducting accelerometer-based
activity assessments in field-based research. Med Sci Sports Exerc
2005;37(11 Suppl):S531-43.
37. Watz H, Waschki B, Meyer T, Magnussen H. Physical activity in
patients with COPD. Eur Respir J 2009;33:262-72.
38. Troosters T, Sciurba F, Battaglia S, et al. Physical inactivity in patients
with COPD, a controlled multi-center pilot-study. Respir Med 2010;
104:1005-11.
39. Steele BG, Holt L, Belza B, Ferris S, Lakshminaryan S, Buchner DM.
Quantitating physical activity in COPD using a triaxial accelerometer.
Chest 2000;117:1359-67.
40. Belza B, Steele BG, Hunziker J, Lakshminaryan S, Holt L,
Buchner DM. Correlates of physical activity in chronic obstructive
pulmonary disease. Nurs Res 2001;50:195-202.
41. McAuley E, Blissmer B. Self-efficacy determinants and consequences
of physical activity. Exerc Sport Sci Rev 2000;28:85-8.
42. Cooper CB. The connection between chronic obstructive pulmonary
disease symptoms and hyperinflation and its impact on exercise and
function. Am J Med 2006;119(10 Suppl 1):21-31.
43. Carron A, Hausenblas H, Mack D. Social influence and exercise:
a meta-analysis. J Sport Exerc Psychol 1996;18:1-16.
44. Katzmarzyk PT, Church TS, Craig CL, Bouchard C. Sitting time and
mortality from all causes, cardiovascular disease, and cancer. Med Sci
Sports Exerc 2009;41:998-1005.
45. Healy GN, Dunstan DW, Salmon J, et al. Breaks in sedentary time:
beneficial associationswithmetabolic risk.DiabetesCare 2008;31:661-6.
www.archives-pmr.org
2402.e1
Supplemental Appendix S1 Validity and Reliability
Information for All TestsPhysical activity in chronic obstructive pulmonary disease
Physical activity: DynaPorta
In comparison with indirect calorimetry, the DynaPort was found to
be one of the best monitors to assess standardized and common
physical activities in the range of intensities relevant to patients
with COPD.1
Supplemental Table S1 Univariate associations between potential pr
Physical Factors
Total Group (NZ113)
% Locomotion
Correlation
Coefficient % Sitting
Age, yjj .183* .098
Height, cmjj .094 .067
Pack-years, y .023 �.001
Exacerbations, no. �.312y .261y
FEV1, Lx .621z �.141*
FEV1/FVC, %xjj .578z �.156*
RV, Ljj �.520z .078
ITGV, Ljj �.466z .120
BMI, kg/m2jj .026 .086
FFM, indexjj .156* .054
VO2peak, mL/min/kgjj .503z �.047
Peak workload, Wjj .569z �.098
6MWD, m .744z �.233y
CIRS-G, total score .013 �.097
mMRC, score �.609z .105
Chair stand, no.jj .404z �.173*
Psychosocial factors
IPQ-R, consequencesjj �.464z .067
IPQ-R, treatment controljj .153* .176*
IPQ-R, illness coherencejj �.168* �.036
IPQ-R, emotional representations �.233y .024
Depression, BDI total score �.229y .009
Self-efficacy, LIVAS total scorejj .324z �.082
SRQ-E, RAI indexjj .210y �.124*
SRQ-E, external regulation �.227y .245y
SRQ-E, introjected regulation �.197y .198y
SRQ-E, identified regulation .046 .109
SRQ-E, intrinsic motivation .094 �.046
Social support, positive of family �.075 .045
Social support, negative of family .012 �.030
Social support, positive friends .070 �.005
Sleep quality, PSQI total score .023 �.047
NOTE. All values are Spearman rho, except as otherwise indicated.
Abbreviations: BDI, Beck Depression Inventory; CIRS-G, Cumulative Illness R
ITGV, intrathoracic gas volume; LIVAS, Dutch version of the Perceived Phy
Council dyspnea index; PSQI: Pittsburgh Sleep Quality Index; RAI, Relative A
* P<.20, the variables indicated with this symbol were included in the regy P<.05, the variables indicated with this symbol were included in the regz P<.001, the variables indicated with this symbol were included in the rex Postbronchodilator.jj Pearson correlation coefficient.
www.archives-pmr.org
Comorbidity: Cumulative Illness Rating Scale forGeriatrics
The Cumulative Illness Rating Scale for Geriatrics2 rates 13 bodysystems on a 5-point (pathophysiological) severity scale. An exten-sive review3 reported that the interrater and test-retest reliability of theCumulative IllnessRatingScale forGeriatrics are good. Furthermore,criterion validity has been confirmed by high correlation coefficientswith scoresbased onautopsies (the criterion standard) andwith scoresbased on health histories and chart reviews. Concurrent validity wasconfirmedby comparisonswith othermeasures of comorbidity. Thereis little evidence to support predictive validity.
edictor variables and percentage locomotion or percentage sitting
GOLD Stages I and II (nZ60)
GOLD Stages III and IV
(nZ53)
% Locomotion
Correlation
Coefficient % Sitting
% Locomotion
Correlation
Coefficient % Sitting
.015 .180* .209* .092
�.004 .146 �.024 .056
�.146 �.077 .000 .074
�.038 .227* �.245* .195*
.029 .130 .478z �.057
.003 �.063 .458y �.053
�.090 �.090 �.426y .024
�.054 �.041 �.430y .058
�.049 .263y �.077 .013
�.007 .294y .071 �.061
.046 .084 .511z �.073
.056 .124 .624z �.134
.438z �.123 .735z �.219*
.115 �.005 �.053 �.151
�.081 .008 �.603z �.076
.200* �.119 .528z �.170
�.190* .166 .296y �.118
.005 .275y .139 .154
.024 �.103 .003 �.064
�.076 .198* �.226* �.156
�.076 .059 �.278y �.090
.202* �.021 .237* �.071
.130 �.036 .191* �.151
�.018 .132 �.316y .302y
�.043 .207* �.283y .219*
.273y .061 �.097 .137
.163 �.077 �.023 .022
.035 �.072 �.126 .041
.040 �.052 �.044 �.027
.050 �.008 �.028 .062
�.067 �.072 .034 .002
ating Scale for Geriatrics; FFM, fat-free mass; FVC, forced vital capacity;
sical Ability Subscale Questionnaire; mMRC, modified Medical Research
utonomy Index; VO2peak, peak oxygen consumption.
ression analyses.
ression analyses.
gression analyses.
2402.e2 J.E. Hartman et al
Pulmonary function: spirometer and bodyplethysmography
Spirometry and body plethysmography measurements were per-formed by trained personnel at the lung function department of thehospital (University Medical Center Groningen). Both were per-formed according to international guidelines.4,5 Forced expiratoryvolume in 1 second, residual volume, total lung capacity, andintrathoracic gas volume were measured.
Dyspnea severity: modified Medical Research Councildyspnea index
The modified Medical Research Council dyspnea index is a ques-tionnaire that consists of 5 statements about perceived breathless-ness: grade 1 (“I only get breathless with strenuous exercise”), grade2 (“I get short of breath when hurrying on the level or up a slighthill”), grade 3 (“I walk slower than people of the same age on thelevel because of breathlessness or have to stop for breath whenwalking at my own pace on the level”), grade 4 (“I stop for breathafter walking 100 meters or after a few minutes on the level”), andgrade 5 (“I am too breathless to leave the house”). The modifiedMedical Research Council dyspnea index was found to be a simpleand valid method of categorizing patients with chronic obstructivepulmonary disease in terms of their disability, which could be usedto complement forced expiratory volume in 1 second in the classi-fication of chronic obstructive pulmonary disease severity.6
Maximal exercise capacity: symptom limitedincremental cycle ergometer test
The symptom limited incremental cycle ergometer testwas performedin line with the American Thoracic Society/American College ofChest Physicians statement on cardiopulmonary exercise testing.7 Amaximal incremental protocol was used with 3 minutes resting, 3minutes unloaded cycling, and approximately 10minutes cyclingwithan individualized incremental load of 5 to 25W per minute.
Functional exercise capacity: six-minute walk distance
The six-minute walk distance was performed according to theAmerican Thoracic Society published guidelines in 2003.8 Patientshad to walk indoors as far as possible during 6 minutes withoutencouragement. Patients were allowed to walk at their own pace, tostop if necessary, and to use oxygen.A practicewalkwas performed,and the highest distance on the 2 tests was used for analyses.
Leg muscle function: 30-second chair stand test
The chair stand test was used to assess leg muscle function. Thetest involves counting the number of times, within 30 seconds, thepatient can come to a full stand from a seated position withoutusing his/her arms. Intraclass reliability was found to be rZ.89(test-retest), and criterion validity related to leg press was found tobe rZ.77 (test-retest).9
Body composition: bioelectrical impedance
Fat-free mass was measured by bioelectrical impedance (Bodystat1500b). Resistance was measured using a 4-surface electrodetechnique at standardized places. Measurements were performed
by trained personnel at the lung function department at thehospital. Fat-free mass was calculated with chronic obstructivepulmonary disease and sex-specific equations.10
Social support for physical activity: Dutch version of theSocial Support for Exercise Behaviors ScaleQuestionnaire
The Dutch version of the Social Support for Exercise BehaviorsScale Questionnaire was originally developed by Sallis et al.11
The questionnaire consists of 3 subscales (friend support posi-tive, family support positive, and family support negative) anda total of 18 items. A study on the internal consistency of theDutch translation of the questionnaire reported Cronbach alpha of.69 (friends support positive), .71 (family support positive), and.26 (family support negative).12
Motivation to exercise: Exercise Self-RegulationQuestionnaire
The Exercise Self-Regulation Questionnaire is one of the Self-Regulation Questionnaires. These questionnaires assess domain-specific individual differences in the types of motivation orregulation. The questions concern the regulation of a particularbehavior (eg, exercising regularly) or class of behaviors (eg,engaging in religious behaviors). The theory behind the ques-tionnaires is the self-determination theory.13 The format for thesequestionnaires was introduced by Ryan and Connell.14 Eachquestionnaire asks why the respondent does a behavior (or class ofbehaviors) and then provides several possible reasons that havebeen preselected to represent the different styles of regulation ormotivation. The first 2 questionnaires were developed for lateelementary and middle school children, and concern school work(Self-Regulation Questionnaire-academic) and prosocial behavior(Self-Regulation Questionnaire-prosocial). Their validation isdescribed in Ryan and Connell.14 Since then, several others havebeen developed that are intended for adults.
Depression: Beck Depression Inventory (BDI)
The Beck Depression Inventory is a self-administrated 21-itemself-report questionnaire on a 3-point rating scale.15 A meta-analysis of the Beck Depression Inventory’s internal consistencyestimated a mean coefficient alpha of .81 for nonpsychiatricsubjects.16 The mean correlations of the Beck Depression Inven-tory with clinical ratings and the Hamilton Psychiatric RatingScale for Depression were .60 and .74, respectively, in nonpsy-chiatric subjects.
Illness perception: Illness Perception Questionnaire
The Illness Perception Questionnaire is a widely used quantitativemeasure of the 5 components of illness representations in theLeventhal self-regulatory model. Analyses provided goodevidence for both the internal reliability of the subscales and theshort- (3wk) and long-term (6mo) retest reliability. The IllnessPerception Questionnaire also demonstrated sound discriminant,known group, and predictive validity.17
www.archives-pmr.org
References
1. Van Remoortel H, Raste Y, Louvaris Z, et al. Validity of six activity
monitors in chronic obstructive pulmonary disease: a comparison with
indirect calorimetry. PLoS One 2012;7:e39198.
2. Linn BS, Linn MW, Gurel L. Cumulative illness rating scale. J Am
Geriatr Soc 1968;16:622-6.
3. de Groot V, Beckerman H, Lankhorst GJ, Bouter LM. How to measure
comorbidity. A critical review of available methods. J Clin Epidemiol
2003;56:221-9.
4. Miller MR, Hankinson J, Brusasco V, et al. Standardisation of
spirometry. Eur Respir J 2005;26:319-38.
5. Wanger J, Clausen JL, Coates A, et al. Standardisation of the
measurement of lung volumes. Eur Respir J 2005;26:511-22.
6. Bestall JC, Paul EA, Garrod R, Garnham R, Jones PW, Wedzicha JA.
Usefulness of the Medical Research Council (MRC) dyspnoea scale as
a measure of disability in patients with chronic obstructive pulmonary
disease. Thorax 1999;54:581-6.
7. American Thoracic Society; American College of Chest Physicians.
ATS/ACCP Statement on cardiopulmonary exercise testing. Am J
Respir Crit Care Med 2003;167:211-77.
8. Brooks D, Solway S, Gibbons WJ. ATS statement on six-minute walk
test. Am J Respir Crit Care Med 2003;167:1287.
9. Jones CJ, Rikli RE, Beam WC. A 30-s chair-stand test as a measure of
lower body strength in community-residing older adults. Res Q Exerc
Sport 1999;70:113-9.
10. Steiner MC, Barton RL, Singh SJ, Morgan MD. Bedside methods
versus dual energy X-ray absorptiometry for body composition
measurement in COPD. Eur Respir J 2002;19:626-31.
11. Sallis JF, Grossman RM, Pinski RB, Patterson TL, Nader PR. The
development of scales to measure social support for diet and exercise
behaviors. Prev Med 1987;16:825-36.
12. Stevens M, Bakker van Dijk A, de Greef MH, Lemmink KA,
Rispens PA. Dutch version of the Social Support for Exercise
Behaviors Scale. Percept Mot Skills 2000;90:771-4.
13. Ryan RM, Deci EL. Self-determination theory and the facilitation of
intrinsic motivation, social development, and well-being. Am Psychol
2000;55:68-78.
14. Ryan RM, Connell JP. Perceived locus of causality and internalization:
examining reasons for acting in two domains. J Pers Soc Psychol
1989;57:749-61.
15. Beck AT, Ward CH, Mendelson M, Mock J, Erbaugh J. An inventory
for measuring depression. Arch Gen Psychiatry 1961;4:561-71.
16. Beck AT, Steer RA, Garbin MG. Psychometric properties of the Beck
Depression Inventory: twenty-five years of evaluation. Clin Psychol
Rev 1988;8:77-100.
17. Moss-Morris R, Weinman J, Petrie KJ, Horne R, Cameron LD,
Buick D. The revised Illness Perception Questionnaire (IPQ-R). Psy-
chol Health 2002;17:1-16.
18. Bosscher RJ, Laurijssen L, de Boer E. Measuring physical self-
efficacy in old age. Percept Mot Skills 1993;77:470.
19. Buysse DJ, Reynolds CF III, Monk TH, Berman SR, Kupfer DJ. The
Pittsburgh Sleep Quality Index: a new instrument for psychiatric
practice and research. Psychiatry Res 1989;28:193-213.
20. Jones PW, Quirk FH, Baveystock CM. The St George’s Respiratory
Questionnaire. Respir Med 1991;85(Suppl B):25-31; discussion
33-7.
21. Jones PW, Quirk FH, Baveystock CM, Littlejohns P. A self-complete
measure of health status for chronic airflow limitation. The St. George’s
Respiratory Questionnaire. Am Rev Respir Dis 1992;145:1321-7.
22. Ware JE Jr, Sherbourne CD. The MOS 36-item short-form health
survey (SF-36). I. Conceptual framework and item selection. Med
Care 1992;30:473-83.
23. van der Zee KI, Sanderman R, Heyink J. A comparison of two
multidimensional measures of health status: the Nottingham Health
Profile and the RAND 36-Item Health Survey 1.0. Quality Life Res
1996;5:165-74.
Physical activity in chronic obstructive pulmonary disease 2402.e3
Self-efficacy for physical activity: Dutch version of thePerceived Physical Ability Subscale Questionnaire
The Dutch version of the Perceived Physical Ability SubscaleQuestionnaire consists of 10 statements referring to physicalcapacities. The patient indicates, on a 5-point Likert scale, wherethey agree or disagree with these statements. The questionnairewas translated in Dutch and tested for use in older adults. Theinternal consistency was found to be high (Cronbach aZ.93), withitem-rest of test correlations ranging from .58 to .84.18
Sleep quality: Pittsburgh Sleep Quality Index
The Pittsburgh SleepQuality Index is a self-rated questionnairewith19 items and 7 component scores (subjective sleep quality, sleeplatency, sleep duration, habitual sleep efficiency, sleep disturbances,use of sleeping medication, and daytime dysfunction). A globalPittsburgh SleepQuality Index score of>5 was found to distinguishgood from bad sleepers (sensitivity 89.6%, specificity 86.5%).19
Acceptable measures of internal consistency (overall CronbachaZ.83), test-retest reliability, and validity were reported.19
Disease-specific health-related quality of life: St.George’s Respiratory Questionnaire
The St. George’s RespiratoryQuestionnaire consists of 76 items thatmeasure 3 components: symptoms (problems caused by specificrespiratory symptoms), activity (restriction of activities by dysp-nea), and impacts (impact on everyday life caused by the disease).The test-retest reliability correlation was found to be rZ.92.20,21
Generic health-related quality of life: RAND 36-ItemShort-Form Health Survey
The Dutch version of the RAND 36-Item Short-Form HealthSurvey22,23 consists of 5 subscales: physical functioning (reli-ability: Cronbach aZ.92), vitality (Cronbach aZ.82), bodily pain(Cronbach aZ.88), general health perceptions (CronbachaZ.81), and change in health status (1-item subscale, no alphaavailable). (Cronbach a from the Dutch manual of the RAND-36.)
Health status: Clinical COPD Questionnaire
The Clinical COPD Questionnaire measured chronic obstructivepulmonary disease-related health status. The questionnaireconsists of 10 items divided into 3 domains (symptoms, func-tional, and mental state), which are scored on a 7-point Likertscale (0Zbest, 6Zworst). Cronbach alpha was found to be high(.91), and good test-retest reliability was reported. Furthermore,significant correlations were found between the Clinical COPDQuestionnaire total score and domains of the Medical OutcomesStudy 36-Item Short-Form Health Survey (rZ.48e.60) and theSt. George’s Respiratory Questionnaire (rZ.67e.72).
Suppliers
a. McRoberts, Raamweg 43, 2596 HN The Hague, TheNetherlands.
b. Bodystat Ltd, PO Box 50, Douglas, Isle of Man, IM99 1DQ, UK.
www.archives-pmr.org
2402.e4 J.E. Hartman et al
Supplemental Appendix S2 Sample Size Calculation
Aim 1: to assess the level and variation of physicalactivity and sitting time in patients with chronicobstructive pulmonary disease
A sample size calculation was performed to establish the adequatesample size that could detect differences in physical activitybetween GOLD stages. This analysis showed that group sizes of30 per GOLD stage (NZ120) would achieve 84% power to detecta difference of 1500 steps between different groups of GOLDstages, assuming that the mean in group GOLD stage I is 6000steps and the mean in group GOLD stage II is 4500 steps, whichestimated group SDs of 2000 (eg, assuming a relatively largespread of the data) and an alpha of 5%.
Supplemental Table S2 Comparisons between groups in percentage o
of variance
Variable
Total Group (NZ113) GOL
% Locomotion % Sitting % Loc
% P % P %
LTOT
User 3.04 <.001y 43.54 .002y
Nonuser 7.33 36.37
Sex
Male 7.10 .182* 37.72 .403 8.85
Female 6.17 36.31 8.54
Smoke status
Current 7.13 .541 36.03 .352 7.99
Not 6.68 37.70 9.28
Work status
Working 7.55 .428 37.87 .790 8.40
Nonworking 6.71 37.18 8.82
Sleep statusz
Good sleeper 6.77 .905 37.85 .233 9.12
Poor sleeper 6.86 35.76 8.07
Use sleep medication
Yes 6.90 .906 32.58 .025y 9.25
No 6.78 37.92 8.69
Living situation
Alone 7.66 .113* 34.64 .046y 9.02
With others 6.49 38.20 8.65
Season
AprileSeptember 7.45 .049y 36.05 .137* 9.47
OctobereMarch 6.17 38.40 7.84
Education level
Low 6.68 .879 36.69 .635 8.51
Middle 6.89 38.48 9.66
High 7.14 37.60 8.40
Abbreviation: NA, not applicable.
* P<.20, the variables indicated with this symbol were included in the regy P<.05, the variables indicated with this symbol were included in the regz Sleep status was based on the Pittsburgh Sleep Quality Index (poor sleep
Aim 2: to assess the independent factors that areassociated with physical activity and sitting time,including physical and psychosocial variables
We performed regression analyses to identify the variables thatwere independently associated with physical activity or sittingtime. With regard to the number of independent variables in themodels to maintain a reliable regression model, we have appliedthe frequently used rule of thumb, stating that you should have atleast 10 cases of data for each independent variable in the model.All variables that had P<0.2 in the univariate analyses wereentered in the model, but the final model included fewer variables.For example, the model of physical activity in the total groupincluded only 6 variables.
f locomotion or percentage of sitting with student t tests or analysis
D Stages I and II (nZ60) GOLD Stages III and IV (nZ53)
omotion % Sitting
%
Locomotion % Sitting
P % P % P % P
NA NA 3.04 .008y 43.54 .025y
5.12 36.86
.726 37.26 .021y 4.70 .646 38.34 .795
32.69 4.37 39.06
.093* 35.78 .809 3.68 .375 37.03 .674
36.22 4.68 38.83
.707 36.01 .989 5.85 .305 41.58 .532
36.05 4.47 38.38
.190* 36.16 .859 4.49 .672 39.50 .230
35.82 4.85 35.65
.617 31.89 .065* 3.77 .422 33.50 .171*
36.68 4.67 39.28
.654 34.28 .177* 5.31 .289 35.27 .201
36.86 4.38 39.50
.030y 35.01 .182* 4.19 .384 37.74 .595
37.40 4.82 39.21
.423 35.50 .566 4.56 .298 38.07 .872
37.78 3.90 39.24
35.60 5.71 39.85
ression analyses.
ression analyses.
er Z Pittsburgh Sleep Quality Index total score >5).
www.archives-pmr.org
Supplemental Table S3 Physical activity per GOLD stage (NZ113)
Variable GOLD Stage I (nZ30) GOLD Stage II (nZ30) GOLD Stage III (nZ32) GOLD Stage IV (nZ21) P
Steps per d 7117.0
(3796.000e18,433.000)
7667.000
(3556.000e13,680.000)
4034.000
(541.000e14,281.000)
2136.000
(236.000e8944.000)
<.001*y
Locomotion time, % per d 8.80�3.30 8.70�2.50 5.40�2.60 3.30�2.10 <.001y
Standing time, % per d 13.20�4.90 13.30�3.90 13.30�5.90 11.00�4.40 .298
Sitting time, % per d 36.10�5.90 36.00�7.80 38.40�10.40 39.00�8.70 .440
Lying time, % per d 40.7 (31.100e59.600) 39.800 (29.500e56.500) 40.100 (30.300e73.200) 43.700 (34.600e67.600) .378*
Physical activity level 1.70�0.03 1.71�0.03 1.56�0.11 1.47�0.12 <.001y
Movement intensity locomotion, g 0.188 (0.151e0.302) 0.207 (0.133e0.286) 0.175 (0.130e0.246) 0.173 (0.131e0.257) .001*z
NOTE. Data are presented as median (range) or mean � SD. Differences between groups were tested with analysis of variance or as otherwise indicated. Physical activity levelZ total energy expenditure/basal
metabolic rate.
Abbreviation: g, average body acceleration.
* Differences between groups were tested with a Kruskal-Wallis test with a Holm-Bonferroni adjustment.y There was no difference between GOLD stages I and II; all other GOLD stages were significantly different from each other.z GOLD stage II was significantly different compared with GOLD stages III and IV.
Supplemental Table S4 Physical activity per BODE quartile (NZ113)
Variable BODE Stage I (nZ37) BODE Stage II (nZ32) BODE Stage III (nZ22) BODE Stage IV (nZ22) P
Steps per d 7906.000
(3556.000e18,433.000)
6689.000
(3557.000e14,281.000)
3940.000
(1082.000e8944.000)
1827.000
(236.000e6737.000)
<.001*y
Locomotion time, % per d 9.30�3.10 7.80�2.50 5.30�2.10 2.80�1.70 <.001z
Standing time, % per d 13.40�4.20 12.60�4.00 13.80�6.70 11.30�4.80 .301
Sitting time, % per d 35.90�6.20 36.90�7.80 38.40�10.70 38.90�9.80 .513
Lying time, % per d 40.300 (31.100e55.500) 39.300 (29.500e59.600) 40.900 (30.300e73.200) 45.900 (35.000e67.600) .183*
Physical activity level 1.73�0.13 1.66�0.13 1.57�0.11 1.44�0.07 <.001z
Movement intensity locomotion, g 0.202 (0.151e0.302) 0.191 (0.133e0.286) 0.178 (0.130e0.257) 0.169 (0.131e0.221) <.001*x
NOTE. Data are presented as median (range) or mean � SD. Differences between groups were tested with analysis of variance or as otherwise indicated. Physical activity level Z total energy expenditure/basal
metabolic rate.
Abbreviation: g, average body acceleration.
* Differences between groups were tested with a Kruskal-Wallis test with a Holm-Bonferroni adjustment.y There was no difference between BODE quartiles I and II; all other BODE quartiles were significantly different from each other.z All BODE quartiles were significantly different.x BODE quartile II was significantly different compared with BODE quartiles III and IV.
Physical
activityin
chronic
obstru
ctivepulmonary
disease
2402.e5
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ives-pmr.o
rg
Supplemental Table S5 Measurement results for potential physical and psychosocial predictors per GOLD stage (NZ113)
Variable GOLD Stage I (nZ30) GOLD Stage II (nZ30)
GOLD Stage III
(nZ32) GOLD Stage IV (nZ21) P
GOLD assessment,
A/B/C/Dxx29/1/0/0 24/4/0/2 0/0/16/16 0/0/3/18 NA
Sex, female 8 (27) 8 (27) 10 (31) 11 (52) z .174
Age, y 68.2�8.9 64.4�6.1 67.2�8.2 57.8�8.7 * <.000jj
Smoke status, current 15 (50) 9 (30) 3 (9) 3 (14) z .001zz
LTOT, yes 0 (0) 0 (0) 3 (9) 11 (52) z <.001jj
BMI, kg/m2 24.8�2.1 26.3�4.3 24.1�3.3 25.3�6.1 * .221
FFM, index 17.0�1.9 17.5�2.5 16.3�1.7 16.2�3.0 * .110
FEV1, % predictedjjjj 94.0 (82.0e119.0) 64.0 (50.0e79.0) 38.0 (30.0e49.0) 23.0 (14.0e29.0) y <.001x
RV, % predicted 122.6�31.3 147.0�36.4 190.7�60.1 247.3�61.6 * <.001x
ITGV%TLC, % 59.1�5.5 63.2�6.9 73.1�6.8 78.6�4.5 * <.001x
VO2peak, mL/min/kg 22.4�4.8 19.7�4.0 14.6�3.7 12.0�4.0 * <.001x
Peak workload, W 135.0�46.0 117.0�34.0 63.0�29.0 35.0�22.0 * <.001{
6MWD, m 512.0 (358.0e646.0) 521.0 (344.0e641.0) 387.0 (60.0e600.0) 351.0 (175.0e576.0) y <.001{
mMRC dyspnea index, score 1.0 (1.0e5.0) 2.0 (1.0e5.0) 2.5 (1.0e5.0) 4.0 (2.0e5.0) y <.001x
BODE Index, score 0.0 (0.0e3.0) 1.0 (0.0e5.0) 3.0 (2.0e8.0) 6.0 (3.0e8.0) y <.001x
CIRS-G, total score 2.5 (0.0e10.0) 3.5 (0.0e6.0) 3.0 (0.0e9.0) 2.0 (0.0e8.0) y .445
CCQ, total score 0.7 (0.2e4.6) 1.6 (0.0e4.6) 1.9 (0.1e4.4) 2.5 (0.6e4.4) y <.001**
Self-efficacy, LIVAS total
score
33.5�7.7 28.7�8.4 26.8�6.8 27.5�5.6 * .004#
SSQ, family positive score 12.0 (10.0e24.0) 14.0 (10.0e40.0) 12.0 (10.0e29.0) 18.0 (10.0e39.0) y .031yy
SSQ, family negative score 3.0 (3.0e9.0) 3.0 (3.0e7.0) 3.0 (3.0e7.0) 3.0 (3.0e7.0) y .456
SSQ, friends positive score 5.0 (5.0e16.0) 5.0 (5.0e20.0) 5.0 (5.0e13.0) 5.0 (5.0e16.0) y .219
BDI, total score 3.0 (0.0e25.0) 5.5 (0.0e30.0) 6.0 (1.0e17.0) 9.0 (1.0e22.0) y .071
NOTE. Data are presented as n (%), mean � SD, or median (range).
Abbreviations: BDI, Beck Depression Inventory; CCQ, Clinical COPD Questionnaire; CIRS-G, Cumulative Illness Rating Scale for Geriatrics; FFM, fat free
mass; ITGV, intrathoracic gas volume; LIVAS, Dutch version of the Perceived Physical Ability Subscale Questionnaire; mMRC, modified Medical Research
Council; NA, not applicable; SSQ, Social Support for Exercise Behavior Scale Questionnaire; TLC, total lung capacity; VO2peak, peak oxygen consumption.
* Differences between groups were tested with analysis of variance.y Differences between groups were tested with a Kruskal-Wallis test.z Differences between groups were tested with a chi-square test with Holm-Bonferroni adjustment.x All GOLD stages were significantly different.jj GOLD stage IV was significantly different than GOLD stages I, II, and III.{ There was no difference between GOLD stages I and II; all other GOLD stages were significantly different from each other.# GOLD stage I was significantly different than GOLD stages III and IV.
** GOLD stage I was significantly different than GOLD stages II, III, and IV; GOLD stage II was significantly different than GOLD stage IV.yy GOLD stage I was significantly different than GOLD stage IV.zz GOLD stage I was significantly different than GOLD stage III and IV.jjjj Postbronchodilator.xx Combined COPD assessment with use of the mMRC scale (GOLD 2011, www.goldcopd.org).
2402.e6 J.E. Hartman et al
www.archives-pmr.org
Supplemental Table S6 Univariate association between quality
of life or health status and percentage locomotion in the total
group (NZ113)
Quality of Life Parameter Correlation Coefficient P
CCQ
Symptom �.257 .006
Functional state �.476 <.001
Mental state �.298 .001
Total score �.418* <.001
SGRQ
Symptoms �.255* .007
Activity �.558* <.001
Impacts �.479 <.001
Total score �.503* <.001
RAND-36
Physical functioning .578 <.001
Social functioning .281 .003
Role physical .478 <.001
Role emotional .235 .012
Mental health .060 .530
Vitality .247* .008
Bodily pain .008 .934
Health perceptions .285* .002
NOTE. A higher score on the CCQ depicts worse health status. A higher
score on the SGRQ depicts worse quality of life. A higher score on the
RAND-36 depicts better quality of life. All correlation coefficient
correlations are Spearman rho or as otherwise indicated.
Abbreviations: CCQ, Clinical COPD Questionnaire; RAND-36, RAND 36-
Item Short-Form Health Survey; SGRQ, St. George’s Respiratory
Questionnaire.
* Pearson correlation coefficient.
Physical activity in chronic obstructive pulmonary disease 2402.e7
www.archives-pmr.org
