Abstract
Background.
People with chronic obstructive pulmonary disease (COPD) are very sedentary; increasing light physical activity (LPA) may help to promote long-term maintenance of physical activity.
Objectives.
We evaluated feasibility and acceptability of Active for Life with COPD, a self-efficacy-enhancing intervention designed to increase LPA.
Methods.
The 10-week intervention included walking, functional circuit training, and behavioral and educational strategies. Measures included attrition, adherence, objectively measured physical activity, and qualitative interviews.
Results.
Thirty-six subjects enrolled in the study; 26 completed the intervention and 19 completed the two-month follow-up. Subjects reported the intervention was enjoyable and beneficial, but disliked the activity log and buddy system. Subjects increased mean time spent standing/stepping by 36 (SD=82) minutes/24 hours (P>0.05); they retained a gain of 21 (SD=88) minutes/24 hours at the two-month follow-up (P>0.05).
Conclusions.
The Active for Life with COPD intervention is feasible, acceptable, and may support long term maintenance of physical activity.
Keywords: light physical activity, sedentary behavior, COPD, self-efficacy
Introduction
The sedentary behavior of individuals with chronic obstructive pulmonary disease (COPD)1–8 places them at increased risk for multiple negative health outcomes, including frailty,9 COPD exacerbations, and mortality.10–20 Although pulmonary rehabilitation is effective in increasing exercise capacity and health-related quality of life, it does not increase the day-to-day time spent in physical activity (PA).2,21,22
Current PA guidelines for older adults23 focus on moderate-intensity exercise that is not feasible for long-term maintenance of physical activity in many people with COPD. Accumulating evidence suggests that substantial health benefits are associated with increasing amounts of light physical activity (LPA).24–30 A systematic review of studies using the National Health and Nutrition Examination Survey dataset found that LPA is favorably associated with obesity, markers of lipid and glucose metabolism, and mortality.31 Replacing 30 minutes of sedentary behavior with LPA has been associated with a 14% reduced mortality risk.32 Recent studies indicate that regular PA is associated with better lung health for people with COPD, including a reduced risk of hospitalization for COPD,12,13 a slower rate of decline in lung function,33 and fewer acute exacerbations.11,14
Comprehensive exercise-specific self-efficacy interventions have been successful in promoting exercise adherence in older adults34 and in people with COPD.35 An exercise-specific self-efficacy enhancing intervention designed to increase moderate-to-vigorous physical activity (MVPA) in people with COPD produced increases in LPA, but not MVPA.35 The increase in LPA was unexpected, but worth pursuing given the growing evidence that supports the benefits of LPA. The exercise-specific self-efficacy enhancing intervention may be more powerful for this population if it targeted LPA instead of MVPA.
We designed a self-efficacy-enhancing intervention to increase LPA in people with COPD, Active for Life with COPD. This manuscript describes the feasibility and acceptability of the Active for Life with COPD intervention and presents preliminary results in a small sample. The primary outcomes of interest for the intervention were objectively measured PA and sedentary behavior. Secondary outcomes of interest included time spent in LPA and MVPA, and the distance walked during a six-minute walk test.
Methods
Study design
This mixed methods study was approved by the appropriate institutional review board; all subjects provided informed consent. The feasibility and acceptability of Active for Life with COPD was examined in two overlapping phases: (1) a small randomized trial to determine subjects’ preference for a 6-week vs 10-week version of the Active for Life with COPD intervention, followed by (2) a quasi-experimental single-arm study to further examine the feasibility and acceptability of individual components of the Active for Life with COPD intervention. Physical activity outcomes were measured before and after the structured intervention and at two months following completion of the intervention. Interviews were conducted at the end of the intervention and at two-month follow-up.
The first phase of the Active for Life with COPD study was conducted to determine the appropriate duration of the intervention; subjects were randomized to either a 6-week or 10-week version. After the first wave of subjects (n=6), it was apparent that some subjects did not believe LPA was beneficial; hence, an educational component focusing on the health benefits of LPA was added to the intervention. The randomization process then continued for a total of 23 randomized subjects (6 from the original intervention prior to the addition of LPA education and 17 from the LPA educationally enhanced intervention), at which point it was clear from interviews that subjects preferred the 10-week intervention. The first 6 subjects (original intervention) helped determine the preferred duration of the intervention and their data were used to calculate attrition because the subject burden for the original intervention was the same as the burden for the LPA educationally enhanced intervention. However, data from the first 6 subjects (original intervention) were not used in analysis of outcomes because the LPA educationally enhanced version of the intervention was thought to be more powerful than the original version.
Thirteen subjects enrolled in the 10-week, single-arm, quasi-experimental second phase of the Active for Life with COPD study, which retained the LPA educational component. In total, 19 subjects completed the intervention and all follow-up measures, but as noted above, 6 of them did not receive the educational component. The flow of subjects is depicted in Figure 1. We report in detail on the 13 subjects who completed the LPA educationally enhanced Active for Life with COPD (hereinafter referred to simply as Active for Life with COPD) and all follow-up measures.
Participants
Participants were diagnosed with COPD and recruited from a local health system. Inclusion criteria were age ≥ 50 years, at least moderate airflow obstruction as reflected by pulmonary function tests with a ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC) of < 0.70 and FEV1 <80% normal predicted value,36 a sedentary lifestyle with < 30 minutes of moderate physical activity five days a week, no other major health problems that limited physical activity, and clinically stable at the time of enrollment. Potential participants were excluded if they had participated in a structured exercise program or pulmonary rehabilitation within the past year.
Intervention
The Active for Life with COPD intervention challenged subjects to increase their total PA (combined LPA and MVPA) by at least 60 minutes per day, with an emphasis on LPA. To accomplish this goal, subjects selected their preferred activities, and adjusted the intensity and duration of each bout of exercise/physical activity based on symptoms and rate of exertion. Physical activities had to be at least LPA and performed in the standing position.
The intervention was composed of structured exercises, a behavioral component that focused on exercise/physical activity, specific self-efficacy-enhancing activities, and an educational component. It included two laboratory-based sessions and one home-based session per week for either 4 or 8 weeks, followed by a 2-week transition to home training that included one laboratory-based session and two home-based sessions a week for a total of either 6 or 10 weeks of structured training.
Each laboratory-based session included (1) 20 minutes of walking, (2) 20–30 minutes of behavioral/educational activities, (3) approximately 1 hour of functional circuit training, and (4) 10–15 minutes of stretching, in that order. Minimal equipment—elastic bands, small balls, and a chair—was required for the functional circuit training and other exercises. Subjects spent as much time as they needed to complete each of the 13 structured activities/stations, and rested as needed to recover from breathlessness. They typically completed one circuit during each lab-based session. The intensity of the exercises and the speed of execution was adjusted to attain a rating of perceived exertion equal to somewhat hard to hard at the end of each circuit, or 13 to 15 on the 20-point Borg scale.37 Subjects were taught how to do the exercises at home and were given a booklet demonstrating each exercise.
Appendix Table 1 summarizes aspects of the behavioral and educational components of the intervention. The behavioral component of the intervention was designed to maximize each of the four sources of self-efficacy: mastery, social modeling, social persuasion, and interpretation of physiological and psychological dimensions.38 Behavioral strategies included wearing a pedometer, setting SMART goals (specific, measurable, attainable, realistic and timely), completing an activity log to document goals and activities accomplished during each week, and a buddy system for social support. The educational component included principles of exercise, health benefits of LPA and negative effects of sedentary time, relapse prevention, and managing physical activity during and after an exacerbation.
Measures
Feasibility.
The feasibility of Active for Life with COPD was measured by recruitment, completion rate, adherence to the intervention, and adherence to physical activity monitoring. Adherence to the intervention was facilitated by allowing subjects to reschedule any sessions missed due to planned absences or unexpected illness.
Acceptability.
Acceptability was assessed by semi-structured interviews at the completion of the structured intervention and at the two-month follow-up. Subjects were asked to describe their general experience with the program, their response to each element of the intervention, and the appropriate duration of the intervention, so that the research team could further refine the intervention. A researcher not otherwise engaged in the study administered interviews, which were audiotaped and transcribed verbatim. Participant names were not recorded on the transcripts to protect confidentiality.
Physical Activity and Sedentary Behavior.
Physical activity and sedentary behavior were objectively measured with two devices: ActivPAL and ActiGraph. Participants wore both devices at baseline, after the structured intervention, and at two-month follow-up. The ActivPAL3 accelerometer (PALtechnologies, Glasgow, Scotland) was used to measure time spent standing, stepping, and sitting/lying. This small rectangular device was taped to the anterior aspect of the thigh, wrapped in plastic film to allow bathing, and worn 24 hours/day for a 7-day period. Substantial evidence supports the reliability and validity of the ActivPAL as a measure of physical activity; it is considered the gold standard measure for sedentary behavior.39,40
The ActiGraph GT3X accelerometer (ActiGraph, Pensacola, FL) was used to measure the intensity of physical activity. The GT3X is a small, light device that is worn clipped to the waist band or belt. Subjects wore it during waking hours for the same 7-day period, but removed it during bathing and other water activities. The ActiGraph is widely used; strong evidence supports its reliability and validity.41,42
Function.
The six-minute walk distance test, which is used widely in pulmonary rehabilitation research,43 was employed in this study as an endurance-based measure of lower extremity physical function. This test was completed at baseline, after the intervention, and at two-month follow-up. Subjects completed the walk in an indoor 100-foot-long hallway. Their oxygen saturation was monitored before and after the test, as well as their ratings of perceived fatigue and shortness of breath.
Sample characteristics
Documented sample characteristics included age, gender, body mass index, airflow obstruction as measured by spirometry, number of comorbid conditions as measured by the Functional Comorbidity Index,44 and lower extremity function as measured by the Short Physical Performance Battery (SPPB).45 SPPB scores range from 0–12, with higher scores indicating better function.45
Data analysis
Quantitative data from the 13 subjects who completed Active for Life with COPD and the two-month follow-up were analyzed with descriptive statistics, repeated measures ANOVA, and nonparametric statistics using IBM SPSS Statistics 24. No differences between the 6-week and 10-week groups were found in PA outcomes (Mann-Whitney U test, P = 0.469). Both groups received the identical educationally enhanced intervention, just delivered over different timeframes, so they were combined for purposes of this analysis. In addition, nonparametric statistics were used to perform a limited analysis of outcomes in 2 subgroups defined by an increase in standing/stepping by a mean of (1) more than or (2) less than 30 minutes/24 hours from baseline to two months after completion of the intervention.
Qualitative interviews were analyzed for all 13 subjects who completed Active for Life with COPD and the two-month follow-up interview. Data were coded with Atlas.ti7 and compared to laboratory notes for context. Initial coding was performed by KW, then reviewed by JLL. Disagreements were discussed and resolved by consensus.
We identified statements related to the experience of participating in the Active for Life with COPD intervention and follow-up: perceptions, impressions, and recommendations regarding each element of the intervention. A subgroup comparison was performed to determine if experiences differed based on the outcome of the intervention, again comparing the experiences of subjects who increased physical activity by at least 30 minutes/day (n=7) or less than 30 minutes/day (n=6) by two-month follow-up.
Results
Fifty-four people who expressed interest were screened for eligibility; 36 were eligible and attended at least one Active for Life with COPD session (Figure 1). Seventy-two percent of subjects (n=26) completed Active for Life with COPD (either original or educationally enhanced), 58% (n=21) completed the intervention and outcome measurements at the end of the structured intervention, and 53% (n=19) completed the intervention and outcome measurements at the end of structured intervention and at the two-month follow-up. The most common reasons for not completing the intervention were related to health (n=5) and transportation (n=3). Two were related to the intervention: one subject could not manage the time commitment and one was not happy with the program and facilities. Overall, subjects attended 79% of sessions. Subjects who completed the Active for Life with COPD intervention (N=26) attended 97% of sessions and the others (N=10) attended 32% of the sessions prior to termination of their participation. No significant differences were found in age, body mass index, airflow obstruction (FEV1 percent predicted and FEV1/FVC), number of comorbid conditions, and distance walked in six minutes between those who did and did not complete the program (See Appendix Table 2).
Adherence to the home-based physical activity component of the intervention was suggested by an increase in time spent standing and stepping, measured at the end of the intervention and described below. Adherence to the process of documenting home-based activities was low. Subjects turned in 42% of the weekly activity logs. Of the activity logs that were turned in, 56% were completely filled out (full 7 days of activity recorded), 38% were partially completed, and 6% were not completed at all. Adherence to physical activity monitoring was high. Subjects wore the ActivPAL device for a mean of 6.8 (SD=0.76) days and the ActiGraph device for a mean of 6.1 (SD=1.1) days at each data collection.
Six men and seven women completed Active for Life with COPD and the two-month follow-up. Their mean age was 70 years (SD=7) and forced expiratory volume in one second was 46% of predicted normal values (SD=17). The number of comorbidities ranged from 1 to 9 and the SPPB scores ranged from 7 to 12. At baseline the mean time spent standing and stepping was 287 (SD=128) minutes/24 hour day. Sample characteristics are described in Table 1.
Table 1.
aResponders n=7 | bNonresponders n=6 | Comparison of responders and nonresponders | Total n=13 | |
---|---|---|---|---|
Gender; male, N (%) | 7 (100%) | 1 (17%) | 8 (62%) | |
Mean (SD) | Mean (SD) | cP | Mean (SD) | |
Age, years | 69.1 (5.0) | 70.7 (9.8) | 0.534 | 70.1 (7.3) |
Forced expiratory volume, % predicted | 35.9 (7.0) | 57.0 (17.8) | 0.035* | 45.6 (16.7) |
Forced expiratory volume/forced vital capacity | .41 (.11) | .56 (.13) | 0.073 | .48 (.14) |
Body mass index | 26.4 (4.6) | 26.6 (8.1) | 0.836 | 26.5 (6.1) |
Functional Comorbidity Index | 4.0 (2.5) | 3.5 (2.9) | 0.628 | 3.8 (2.7) |
Short physical performance battery, total score | 11.4 (0.8) | 9.7 (2.3) | 0.234 | 10.6 (1.9) |
Six-minute walk distance, feet | 1424 (329) | 1243 (277) | 0.295 | 1340 (308) |
Standing/stepping, minutes/24 hour. | 208 (120) | 380 (54) | 0.022* | 287 (128) |
Sit/lie, minutes/24 hours | 1232(120) | 1060 (54) | 0.022* | 1153 (128) |
Abbreviation: SD, standard deviation
Responders increased time spent standing and stepping by ≥ 30 minutes/24 hours as measured by ActivPal.
Nonresponders increased time spent standing and stepping by < 30 minutes/24 hours as measured by ActivPal.
Mann-Whitney U Test
p-value <0.05
In general, subjects were very pleased with Active for Life with COPD. The majority (12/13) found it to be enjoyable and beneficial; some asked to enroll in future Active for Life with COPD groups. The individual elements were rated as highly beneficial and motivating: goal setting (by 9/13 subjects), pedometers (12/13), breathing problems action plan (10/13), and follow-up phone coaching (9/13). A minority of subjects found the home-based activity log and the buddy system to be helpful.
Although this study was not powered to detect treatment effects, the data provide a preliminary indication of potential effects (Table 2). Subjects increased the mean time they spent standing/stepping by 36 (SD=82) minutes/24 hours at the end of structured training and retained a gain of 21 (SD=88) minutes/24 hours at two months after completion of training, and time spent sitting/lying decreased proportionately; however, this was not statistically significant. ActiGraph data demonstrated no significant change in the time spent in LPA or moderate physical activity. The distance walked in six minutes increased by 128 (SD=162) feet at the end of structured training and a gain of 61 (SD=119) feet was retained at the two-month follow-up (univariate repeated measures ANOVA; P=0.012).
Table 2.
Physical Activity Measure | Before Mean (SD) | After up Mean (SD) | 2-month follow-up Mean (SD) | P |
---|---|---|---|---|
ActivPAL, sitting/lying minutes/24 hours | 1153(128) | 1115 (135) | 1131(115) | .247 |
ActivPAL, standing/stepping minutes/24 hours | 287 (128) | 324 (134) | 309 (115) | .254 |
ActiGraph, LPA minutes/day (waking hours) | 203(96) | 227 (116) | 214(95) | .214 |
ActiGraph, MVPA minutes/day (waking hours) | 3 (3) | 13 (20) | 12 (17) | .055 |
Six minute walk distance, feet | 1,340 (308) | 1,468 (276) | 1,401 (305) | .012* |
Abbreviations: SD, standard deviation; LPA, light physical activity; MVPA, moderate-to-vigorous physical activity
Repeated measures ANOVA, univariate two-tailed test
p-value <0.05
Sixty-nine percent of subjects demonstrated some increase in their physical activity at two months after completion of the Active for Life with COPD intervention, but the magnitude of increase ranged widely from 14 minutes/24 hours to 132 minutes/24 hours. To identify potential predictors of response, we created 2 subgroups: responders (n=7), who increased standing/stepping by more than 30 minutes/24 hour and non-responders (n=6), with a smaller or no increase. Comparison of baseline measures for the two subgroups demonstrated a significant difference in the degree of airflow obstruction and the 6-minute distance walk. Responders had greater airflow obstruction at baseline, with a mean forced expiratory volume of 35.9% of predicted normal values (SD=7) and lower minutes standing/stepping at baseline (mean=208, SD=120) compared to non-responders (Mann-Whitney U test, P=.035 and P=0.022). There were no other statistically significant differences (Table 1).
Based on interview data, subject experiences for both subgroups were fairly similar. However, two differences were noted: the non-responders had more serious comorbid conditions and faced barriers like lack of social support from their families. See Appendix Table 3 for qualitative data summary.
Discussion
The results suggest that the Active for Life with COPD intervention is both feasible and acceptable for people with COPD and moderate-to-severe airflow obstruction. Among those who completed the study, adherence was high and most components of the intervention were found to be useful.
The high attrition rate observed in this study is not surprising, given the health status of people with COPD and the nature of the intervention, but it is concerning. Clinical trial guidelines recommend no more than 20% attrition to avoid biasing results. However, this is challenging in COPD studies, because people with COPD have multiple comorbid conditions and their physical activity is limited during acute exacerbations.46 The latest Cochrane review of pulmonary rehabilitation in COPD47 reported average attrition rates of 20% for 53 clinical trials; 43% of those trials exceeded 20% and 23% exceeded 30%. In this preliminary study, the relatively short two-month follow-up period increased attrition, because subjects did not have time to recover from an exacerbation, return to LPA before the end of the follow-up, and complete follow-up measures.
We observed very high adherence to the laboratory-based portion of the intervention, but did not directly monitor adherence to the home-based portion of the intervention. The unusually high level of attendance of people who completed the intervention was facilitated by our policy that allowed people to schedule make-up sessions within a few weeks in cases of illness or planned absence. This level of flexibility is important with a complex and challenging intervention, because people with COPD are dealing with fluctuating symptoms, acute exacerbations, and multiple comorbid conditions. The high level of adherence is strong evidence for the acceptability of this intervention.
Subjects also provided evidence for the acceptability of individual elements of the Active for Life with COPD intervention. Most elements of the program were viewed positively, but two, the home-based activity log and buddy system, were not considered helpful and should be omitted from future versions of the intervention.
The retained gain of 21 minutes/day of LPA may sound modest, but it adds up to 147 minutes a week, which is close to the recommended 150 minutes a week of moderate physical activity recommended for older adults, albeit less intense.23 It also has the benefit of reducing sedentary time. The observed increase in LPA is consistent with an earlier version of this intervention that was designed to increase MVPA.35 In that study, subjects had increased LPA by the end of a 4-month intervention by a mean of 21 (SD=30) minutes/day; subjects in two control groups decreased LPA by −22 (SD=48) minutes/day and −25.73 (SD=52) minutes/day. However, all gains were lost by one-year follow-up. The participants in the Active for Life with COPD study were encouraged to increase LPA with the idea that the intervention would be more sustainable over time. Subjects did retain 42% of the gains in physical activity for two months.
The minimal clinically important difference for the six-minute walk distance in people with COPD is 82 feet.48 So the observed increase in six-minute walk distance was clinically significant immediately after the intervention, but not at two-month follow-up. This is not surprising, as the Active for Life with COPD intervention does not address speed of walking.
While some individuals exceeded the goal of increasing LPA by 60 minutes a day, the group as a whole fell short of the goal, which raises a question about its appropriateness, since an overly ambitious goal could have a negative effect on self-efficacy. However, the goal was well within the exercise guidelines established by the American Thoracic Society/European Respiratory Society (ATS/ERS)49 and the American Association of Cardiovascular and Pulmonary Rehabilitation (AACVPR),50 which recommend higher intensity activity. Based on the results of this study we conclude that the 60-minute goal for LPA is challenging for subjects, yet feasible when it can be accomplished with very light activities such as standing. Nevertheless, it warrants further evaluation.
At baseline, responders had significantly greater airflow obstruction and lower physical activity levels, but a slightly higher functional capacity as reflected by the six-minute walk test than did non-responders. This would suggest that responders had been functioning on a day-to-day basis at a lower fraction of their functional capacity and thus had more room to increase physical activity levels.51 These results are interesting, but should be interpreted with caution because of the small sample size.
Limitations of this research include the small sample size and lack of power to detect potential effects of the intervention. There was no control group and the post-intervention follow-up was short.
Conclusion
We conclude that the Active for Life with COPD intervention is feasible with high adherence; however, high attrition occurred due to subjects’ health status. The intervention is acceptable with two modifications: deletion of the home-based activity log and the buddy system. Physical activity benefits were sustained for two months after the end of the intervention, suggesting that Active for Life with COPD may support long term maintenance of PA. A larger RCT with longer follow-up will be required to determine long-term maintenance effects of the Active for Life with COPD intervention.
Highlights.
The Active for Life with COPD intervention is feasible and acceptable
Subjects were very pleased with the Active for Life with COPD intervention
Light physical activity increased by 36 minutes/24 hours after the intervention
Acknowledgments:
K.E.W. is supported by T32 predoctoral fellowship NIH/NINR NR016914-01, Complexity: Innovations in Promoting Health & Safety.
Abbreviations:
- PA
physical activity
- LPA
light physical activity
- MVPA
moderate to vigorous physical activity
Appendix Table 1.
Activities used to optimize each source of self-efficacy |
---|
Mastery
|
Social modeling
|
Social persuasion
|
Physiological and psychological feedback system
|
Educational component |
Physical activity education:
|
Physical activity relapse prevention for:
|
Breathing Problems Action Plan
|
Follow-up activities to support long-term maintenance |
|
Abbreviations: PA, physical activity; COPD, chronic obstructive pulmonary disease; LPA, light physical activity; MVPA, moderate-to-vigorous physical activity
Appendix Table 2.
aCompleters n=26 | bNoncompleters n=10 | Comparison of completers and noncompleters | Total n=36 | |
---|---|---|---|---|
Mean (SD) | Mean (SD) | P | Mean (SD) | |
Age, years | 70.4 (6.8) | 66.8 (9.2) | 0.133 | 69.1 (7.5) |
Forced expiratory volume, % predicted | 45.6 (15.8) | 54.1 (17.0) | 0.816 | 47.8 (10.3) |
Forced expiratory volume/forced vital capacity | .46 (.13) | .51 (.14) | 0.713 | .48 (.13) |
Body mass index | 28.8 (6.7) | 26.2 (6.3) | 0.913 | 28.1 (6.6) |
Functional Comorbidity Index | 4.0 (2.3) | 4.0 (1.6) | 0.181 | 4.0 (2.1) |
Short physical performance battery, total score | 10.7 (1.6. | 10.8 (1.7) | 0.896 | 10.7 (1.6) |
Six-minute walk distance, feet | 1302 (345) | 1370 (443) | 0.835 | 1321 (370) |
Abbreviation: SD, standard deviation
Completers finished the Active for Life intervention.
Noncompleters started but did not finish the Active for Life intervention
Appendix Table 3.
Subject Groups by Intervention Outcome | Subject Experiences | Example Quotes |
---|---|---|
Increased physical activity by at least 30 minutes |
|
|
N=7 | ||
Did not improve physical activity |
|
|
N=6 |
Abbreviations: LPA, light physical activity; AECOPD, acute exacerbation of chronic obstructive pulmonary disease; PA, physical activity
Footnotes
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Declarations of interest: none
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