| | A Randomized Clinical Trial of an Activity and Exercise Adherence Intervention in Chronic Pulmonary DiseaseAbstract Steele BG, Belza B, Cain KC, Coppersmith J, Lakshminarayan S, Howard J, Haselkorn JK. A randomized clinical trial of an activity and exercise adherence intervention in chronic pulmonary disease. ObjectivesTo evaluate the effectiveness of an exercise adherence intervention to maintain daily activity, adherence to exercise, and exercise capacity over 1 year after completion of an outpatient pulmonary rehabilitation program. DesignA 2-group, experimental design was used with randomization into intervention and usual care groups. SettingOutpatient pulmonary rehabilitation program in a university-affiliated medical center. ParticipantsOne hundred six subjects (98 men; 98 with chronic obstructive pulmonary disease) with a mean age of 67 years and chronic lung disease. InterventionTwelve-week adherence intervention (weekly phone calls and home visit) including counseling on establishing, monitoring, and problem-solving in maintaining a home exercise program. Main Outcome MeasuresPrimary outcomes included daily activity (accelerometer), exercise adherence (exercise diary), and exercise capacity (six-minute walk test). All measures were performed at baseline, after the pulmonary rehabilitation program (8wk), after the adherence intervention (20wk), and at 1 year. ResultsA rank-based analysis of covariance showed less decline at 20 weeks in exercise adherence (intervention mean, +3min; control mean, −13min; P=.015) and exercise capacity (intervention mean, −10.7m; control mean, −35.4m; P=.023). There were no differences in daily activity at 20 weeks or any differences in any primary variable at 1 year. ConclusionsThe intervention enhanced exercise adherence and exercise capacity in the short term but produced no long-term benefit. These findings are in part attributed to the disappointing measurement characteristics of the accelerometer used to measure daily activity. The intervention was acceptable to participants. Further study is needed to fashion interventions that have more persistent benefit. CHRONIC PULMONARY DISEASE is a major cause of morbidity and mortality in modern society. Chronic obstructive pulmonary disease (COPD), the most prevalent chronic lung disease, is on the increase and is anticipated to be the fourth leading cause of death by 2020.1, 2 Even more compelling than the lethality of COPD, the chronicity and increasing debilitation associated with it often plays out over decades, with gradual loss of physical function and reduced quality of life (QOL) due to dyspnea, fatigue, and other symptoms. Pulmonary rehabilitation improves physical functioning, dyspnea, and QOL and is now considered an integral part of optimal care for persons with severe lung disease.1, 2, 3 Because most pulmonary rehabilitation programs involve only a few months of supervised outpatient exercise classes and education, fundamental questions persist about the long-term benefits of these programs because adherence to regular exercise does not appear to continue after supervised classes stop.4, 5, 6 In contrast to traditional, facility-based pulmonary rehabilitation, exercise programs carried out in the homes of COPD patients can be effective in maintaining dyspnea reduction and exercise endurance.7, 8, 9, 10 In a controlled trial, Strijbos et al11 found that a home-based exercise program with visiting physical therapists resulted in equal improvements in maximal cycle work, distance walked, and dyspnea reduction compared with a similarly rigorous hospital-based outpatient program. Perhaps more significantly, these investigators also found that the home exercise program resulted in better postprogram sustained improvement in maximal exercise tolerance and walking distance compared with a hospital-based exercise group at the end of the 18-month follow-up period. Consistent with the extensive literature on exercise adherence of Dishman,12, 13 others have concluded that chronic pulmonary disease patients are more likely to incorporate regular exercise into their lifestyles and maintain functional gains from pulmonary rehabilitation if they attend programs that combine hospital or clinic-based outpatient programs with dyspnea management training and supervised home exercise.11, 14, 15 These findings have been echoed by others who have recommended supervised home exercise programs for the frail elderly.16, 17 More recently, Ries et al18 performed a randomized trial of an exercise maintenance intervention that included weekly phone calls and a monthly supervised exercise session in people with COPD who had just completed pulmonary rehabilitation. They found that their intervention produced only modest retention of program benefits over a 2-year period. Ries did not attempt to measure exercise adherence during this study, although a post hoc analysis of their data by Heppner et al19 evaluated walking exercise in this group. They found that regular walkers had significantly better QOL, less dyspnea, and better walking self-efficacy than people who walked less consistently. These findings suggest that post−pulmonary rehabilitation adherence to exercise, which is largely reflected by walking in this group, may play a role in the maintenance intervention and functional outcomes such as 6-minute walk distance. The purpose of this study was to evaluate the effectiveness of an exercise adherence intervention after a pulmonary rehabilitation program to maintain program levels of daily activity and exercise as well as standard pulmonary rehabilitation outcomes such as exercise capacity, symptom experiences, QOL, health status, and walking self-efficacy. We compared the effects of the adherence intervention with those of usual care after pulmonary rehabilitation, at completion of the 3-month intervention (20wk) and at 1 year. To our knowledge, this study is unique in that, unlike previous work, it prospectively evaluated relationships between exercise adherence (daily activity and exercise duration) during home-based exercise sessions, with standard pulmonary rehabilitation outcomes such as exercise capacity, QOL, and symptom experiences over time. Knowledge of these relationships is important to better understand the role of continued postprogram, unsupervised exercise and daily activity in the persistence of pulmonary rehabilitation functional outcomes and to inform interventions to support these gains. Methods  Design The study was a randomized controlled trial of an exercise adherence intervention and used an intention-to-treat format. The study was approved by the institutional review board. Patients who completed an 8-week, outpatient pulmonary rehabilitation program were randomized to receive either the intervention (n=52) or usual care (n=54). There were several components to protocol implementation and randomization: (1) recruitment; (2) eligibility screening and time 1 (baseline) testing; (3) pulmonary rehabilitation exercise and educational program at weeks 8 through 10 and time 2 (prerandomization) measurement during the final week of pulmonary rehabilitation, then randomization into intervention and control groups using a block design of 10 subjects per block (5 intervention, 5 control); (4) exercise adherence intervention, weeks 9 through 20; and (5) short-term, postintervention testing (time 3) around week 20 and long-term testing (time 4) around 1 year. Study Sample We recruited subjects with chronic lung disease and shortness of breath from the outpatient clinics of a university-affiliated medical center between January 2001 and July 2004; all but 5 subjects were recruited from the pulmonary and general internal medicine clinics. Recruitment was accomplished by flyers provided to health care providers and posters announcing the study in clinic waiting areas. Inclusion criteria were self-reported diminished physical functioning related to a pulmonary problem, pulmonary function impairment, ambulatory, able to read and speak English, and at least 45 years old. Exclusion criteria were inpatient admission within the past 2 months, asthma with episodic abnormality in pulmonary function, pulmonary exacerbation within the past 2 weeks, unstable cardiopulmonary or sensorimotor problems, daily use of a motorized cart, already exercising at least 30 minutes 3 or more days a week, impairment of cognition or communication, active malignancy or rapidly declining clinical course with expected survival of less than 1 year, suboptimal medical management, and/or history of drug or alcohol treatment within the past 6 months. In all, 156 subjects were entered into the study. Approximately one third of these participants (n=50) did not complete pulmonary rehabilitation because of illness exacerbation, travel difficulties, or lack of interest. One hundred six subjects completed pulmonary rehabilitation and were randomized into intervention and control groups. The control group consisted of continuing care with the referring provider and individual recommendations for continuation of the exercise program. Patients were also invited to attend the lung club group sessions. Over the course of the intervention, 4 subjects were lost because of lack of interest, malignancy, and death; over the follow-up period after the intervention, 9 subjects were lost because of COPD exacerbation, malignancy, pain problems, lack of interest, or death. Measurement All measures were performed at 4 time points with the exception of the Charlson Comorbidity Index (CCI),20 which was evaluated at baseline and 1 year. Primary outcomes were (1) daily activity, (2) self-reported daily exercise, and (3) functional capacity. Secondary outcomes included QOL, symptom experiences, health status, and walking self-efficacy. Comorbidities Comorbid conditions may be substantial in persons who have chronic pulmonary disease and impact variables of interest over the study. We used the CCI to assess the burden of comorbid medical conditions.20 Daily activity Daily activity was defined as all physical activity when awake and was measured as body movement in vector magnitude units (VMU), a raw index of movement, using the RT3 accelerometera on four, 6-day measurements at home. An average of the daily activity in VMU performed over the 6 days was computed (VMU summed over 6 full days of wearing divided by 6) to arrive at a value for daily activity. Accelerometers have attained criterion standard status in the measurement of energy expenditure, comparing favorably with such criterion measures as oxygen consumption, doubly labeled water, and direct observation of physical activity.21, 22, 23, 24, 25 These findings are supported by our previous work in pulmonary patients using the TriTrac-R3D.26, 27, 28 Since our earlier studies, the TriTrac-R3D has been substantially modified, although performance data cited at the Stayhealthy.com web site29 showed similar excellent measurement characteristics. Exercise adherence Subjects completed a daily activity diary each evening the accelerometer was worn. Exercise adherence was defined as those activities undertaken for exercise purposes, not routine daily activities. Daily exercise was computed by adding up the total minutes of exercise each day. QOL and symptom management The Seattle Obstructive Lung Disease Questionnaire (SOLDQ) is a self-administered questionnaire measuring 4 dimensions of QOL in chronic pulmonary disease: physical and emotional functioning, coping skills, and treatment satisfaction. The tool has excellent reliability, validity, and responsiveness to outcomes of pulmonary rehabilitation in COPD patients.30, 31, 32 Functional capacity Functional capacity, defined as the maximal physical potential for each person, was measured as the best of 2 sequential 6-minute walks. Unlike conventional maximal exercise testing, walking tests are thought to be a better measure of functional exercise capacity, defined as a person’s ability to undertake physically taxing activities encountered in everyday life.28 Research conducted over the past 2 decades has determined that the 6-minute walk has excellent criterion validity compared with the criterion standard of maximal exercise testing as well as good reliability and responsiveness to changes in exercise capacity.33, 34 Symptom experiences Dyspnea, the most prevalent and disabling symptom experienced in chronic lung disease, was measured as dyspnea level today and during the past 30 days using the dyspnea subscales of the Functional Status and Dyspnea Questionnaire.33, 34, 35, 36 Fatigue, also highly prevalent in chronic lung disease, was measured using the Multidimensional Assessment of Fatigue Scale (MAFS).37, 38 The MAFS contains 16 items and measures a global fatigue index as well as 5 dimensions of fatigue: degree, severity, distress, impact on activities of daily living, and timing. Health status The 36-Item Short-Form Health Survey (SF-36V) was used to measure general health status and included the following domains: physical functioning, role−physical functioning, bodily pain, vitality, social functioning, role−emotional functioning, and mental health.39 Prior versions of the SF-36 have been used to measure functional outcomes in pulmonary patients during pulmonary rehabilitation and other interventions.40 Walking self-efficacy Walking self-efficacy is self-administered and was measured using the Walking Self-Efficacy Questionnaire.41 The questionnaire asks subjects to endorse or reject 9 statements describing a full range of walking intensity. Measurements of self-efficacy expectations for walking have shown good concurrent validity with measures of pulmonary function, diffusing capacity, exercise tolerance, and arterial blood gases.42 Pulmonary Rehabilitation Program and Exercise Adherence Intervention Pulmonary rehabilitation Before being randomized to either the exercise adherence intervention or the control group, all subjects completed a comprehensive pulmonary rehabilitation program that included exercise and education consistent with guidelines of the American Association of Cardiopulmonary Rehabilitation.43 The 1-hour exercise sessions were conducted in a supervised setting with groups of 3 to 6 participants, 2 times a week for 8 weeks. Each session consisted of warm-up and cool-down exercises, progressive resistance exercises with hand weights, elastic resistance tubing, and/or weight machines. Cardiovascular and endurance training included use of treadmills, stationary cycles, NuStep,b and upper-extremity ergometers. The duration and intensities were advanced as tolerated. All participants were monitored throughout the exercise sessions (electrocardiogram, oxygen saturation, heart rate, and blood pressure pre-exercise, during, and postexercise). The education component combined instruction and participation in the topics of pulmonary disease overview, self-management strategies, pharmacology, nutrition, and exercise, presented by topic-specific health care professionals. Exercise adherence intervention The exercise adherence intervention was divided into 2 phases: (1) weeks 1 through 4: establishing a home- and community-based exercise program with emphasis on walking, including skills development in exercise equipment and monitoring devices and (2) weeks 5 through 12: implementing a regular program of exercise, at least 20 minutes, 4 days a week. The latter included more emphasis on self-monitoring and recording of exercise sessions, development of problem-solving skills to prevent or manage exercise lapses, and encouragement to participate in exercise outside the home at least once a week, preferably with another person or group. The adherence intervention consisted of weekly phone calls and 1 home visit over 3 months. The phone calls followed a short, semistructured interview format, including queries about exercise adherence, problem-solving about exercise maintenance, discussion and recommendations about health problems, and encouragement. The home visit evaluated home safety and provided assistance in establishing an individualized exercise routine for home and community use in local senior centers, parks, and other venues. In addition, the experimental group received a digital pedometer for self-monitoring and an exercise handbook that described aspects of the program in more detail. Statistical Analysis The investigation was powered on daily activity change after the adherence intervention. The primary reason the investigators chose to power the study on daily activity was because previous work using the TriTrac-R3D accelerometer showed significant differences in daily activity on pulmonary rehabilitation days compared with preprogram days and at-home exercise days when no exercise was reported.2 These findings predicted that 60 subjects in each group would result in a power of 90% to detect differences of 0.6 standard deviations (SDs) in change in daily activity between intervention and control groups. An additional, compelling reason to use the quantitative accelerometer measure to infer exercise adherence from daily activity was the well-known superiority of these devices to measure exercise duration compared with self-report.21, 24, 44 Means and SDs were computed for all outcome variables at each time point and displayed in tables and plots. Because not all subjects had follow-up data on selected variables, we elected to include only those subjects in the initial and prerandomization analysis who had either short- or long-term follow-up data on that variable. Many of the outcome variables are non-normally distributed. Conover and Iman45 have proposed a method for nonparametric analysis of covariance (ANCOVA) in such a case. The rank transformation is first applied to the outcome variable and to each covariate, meaning that the data values are replaced by their ranks. Then a standard ANCOVA is performed using the rank-transformed covariates and the factor of interest (study group) to predict the rank-transformed outcome variable. At both short-term and long-term outcome measurement points, this nonparametric ANCOVA procedure was used to test for treatment differences in each outcome variable at that time, while controlling for the values of the outcomes variable at baseline and prerandomization. Results As seen in figure 1, 102 of 111 randomized subjects provided outcome data at week 20 while data were missing on 9 subjects at week 20. However, 4 of these 9 missing subjects did later provide data at week 52, so that the total number of subjects providing some follow-up data at either 20 or 52 weeks was 106, 54 in the control group and 52 in the intervention group. Eighty-five of the 106 subjects had COPD. Twelve subjects in the intervention group and 9 in the control group had interstitial lung disease, apnea-hypoventilation syndrome, or sleep apnea. The intervention group included 32 participants who had either severe or very severe COPD, whereas the control group had 38 in these staging groupings. For subjects with COPD, staging of disease severity was defined in accordance with the Global Initiative for Chronic Obstructive Lung Disease (GOLD).1 See table 1 for a breakdown of GOLD staging in both groups. | | |  | GOLD Stage | Intervention Group (n=50) | Control Group (n=52) | |
|---|
| No COPD | 12 | 9 | | | Stage I: mild (%FEV1 >80%) | 0 | 0 | | | Stage II: moderate (%FEV1 >50% and <80%) | 8 | 7 | | | Stage III: severe (%FEV1 >30% and <50%) | 24 | 22 | | | Stage IV: very severe (%FEV1 <30%) | 8 | 16 | | | | |
Thirty-six (45%) of participants used oxygen for at least 8 hours a day, and 4 (5%) were current smokers. Participants improved significantly after pulmonary rehabilitation with regard to exercise capacity, dyspnea reduction, health status, and QOL. The rank-based ANCOVA of daily activity at completion of the adherence intervention (short term) showed no statistically significant difference between the intervention and control groups (P>.20). However, analysis of exercise capacity measured by 6-minute walk and self-report of daily activity did show an intervention benefit. Six-minute walk distance showed a significantly longer short-term distance in the intervention group compared with the control group, after controlling for prerandomization values (P=.023). Table 2, Table 3 show primary outcomes before and after randomization and table 4 shows the secondary outcomes. The 6-minute walk distance decreased less during the exercise adherence intervention in the intervention group (mean ± SD, –10.7±63.1m) than in the control group (mean, –35.4±49.1m). Self-reported minutes of exercise activity also shows a significant difference (P=.015). Minutes of activity increased during the intervention in the intervention group (mean, 3±39min) and decreased in the control group (mean, –13±26). At 1 year (time 4), there are no significant differences between the intervention and control groups after controlling for prerandomization values on any of the 3 outcome measures. The time point means differ for the intervention and control groups in some instances—for example, control group, time 2, because the means were computed only on those subjects who had study data for the time points represented. With regard to the conduct and cost of the intervention, 2 physical therapists phoned study participants, on average, 11.0±1.1 times; 47 of 50 subjects who completed the intervention received at least 11 phone calls, and 3 received at least 9. Regarding home visits, most were conducted in the homes of participants (n=45 [90%]), with a few visits (n=5 [10%]) conducted at the Veterans Affairs exercise facility or at other community settings. The duration of each home visit was 58.5±11.7 minutes. Additional intervention costs included pedometers at $15 each and intervention material printing costs of about $3 per unit. The total mean cost of the intervention for each subject in the adherence intervention group was $134±$36; the range of costs was between $76 to $221, including phone calls and travel expenses. The usual care control group did not include any planned contact with pulmonary rehabilitation participants after the program so there was no related cost. Discussion This largely home-based intervention showed short-term maintenance of self-reported adherence to exercise and persistence of exercise capacity benefits compared with a nonintervention control group. Like other programs that used an adherence intervention post hoc, however, results persisted for only the duration of the intervention. The primary endpoint of daily activity measures by accelerometer did increase more during the exercise adherence intervention in the intervention group than in the control group, but after controlling for baseline differences this was not statistically significant. However, self-reported exercise activity did show a significant intervention effect, even though this effect did not persist long term. The apparent difference between null findings at 20 weeks on daily activity and significantly better self-reported exercise adherence in the experimental group could be due to reporting bias in the self-report measure, because these subjects were aware of their membership in the experimental group and might have been motivated to overreport their exercise duration. There were statistically significant improvements in the 6-minute walk distance in the intervention group that persisted in the long term. This is an indirect measurement of exercise activity, but it is more objective and less subject to reporting bias than is self-reported activity, supporting the idea that the intervention did have a real, functional benefit. This improvement in function is similar to that described by Ries et al18 who used a similar randomized trial of a phone-based intervention to maintain gains after pulmonary rehabilitation. Ries18 also reported benefits of the intervention for 6-minute walk distance and health status but no difference in symptoms or QOL, which declined after pulmonary rehabilitation. This decline continued for all outcomes over the second year postrehabilitation but did not quite reach prerehabilitation baseline. A thorough comparison of their outcomes with the present study is difficult, however, because the Ries study did not control for baseline differences in daily activity and other variables. Heppner, a coinvestigator on the Ries study, evaluated patient adherence to regular walking and its role in long-term maintenance of improved symptoms and QOL after pulmonary rehabilitation in a separate, post hoc analysis.19 Controlling for baseline measures of lung function, QOL, dyspnea, and age, she found that regular walkers had significantly better QOL, less dyspnea, and better walking self-efficacy than people who walked less consistently. Heppner’s findings19 suggest that adherence to exercise, which is largely reflected by walking in this group, is a key mediating variable between any intervention and functional outcomes such as 6-minute walk distance. With regard to our current work, although the intervention was not successful in preventing the regression of post−pulmonary rehabilitation health outcomes over time, it is noteworthy that participant performance remained above pre−pulmonary rehabilitation levels with respect to self-reported exercise and 6-minute walking distance despite the well-known declining trajectory of function in this population. This finding suggests that pulmonary rehabilitation benefits in general are more subtle, possibly related to persistence of walking. Exercise Adherence After Pulmonary Rehabilitation There are few long-term studies of the persistence of benefits from pulmonary rehabilitation. Overall, benefits seem to decline after 6 to 12 months after a formal program and remain somewhat improved compared with control participants after 6 months in most studies.4, 5, 46, 47 Various strategies to maintain pulmonary rehabilitation benefits have been investigated. Distractive stimuli such as listening to music seems to have a short-term benefit.48 Continuing rehabilitation for a more prolonged period, attending a maintenance program with telephone support, or repeating a course of rehabilitation all seem to provide minimal adherence benefit.20, 49, 50 On the other hand, Strijbos et al11 and other investigators6 found that COPD patients were more likely to have pulmonary rehabilitation gains persist and even continue to improve up to a year when they attended programs that combined a supervised home exercise component using home care nurses or physical therapists with the traditional outpatient pulmonary rehabilitation program. The confluence of research regarding home exercise programs suggests that an adherence intervention that is home-based might result in more successful adoption of long-term exercise because (1) they diminish the travel burden on participants, (2) exercise is more readily integrated into daily routines when it is performed at home, and (3) more expensive outpatient program visits are less frequent and are focused on getting the patients started, determining safety, and establishing baseline knowledge about managing the disease. Predictors of Exercise Adherence Fairly strong baseline personal predictors of short-term postintervention daily activity and exercise that reached statistical significance (P<.05) are daily activity, 6-minute walk distance, age, level of obstructive lung disease, and walking self-efficacy. In this study, subjects who felt greater confidence in their abilities to undertake higher levels of daily activity were more likely to do so. This finding is similar to that reported by Heppner et al.19 We found that self-reported short-term daily activity is predicted by baseline values of daily activity, age, CCI score, and walking self-efficacy. These findings are consistent with those of Garcia-Aymerich et al,50 who found that in general, comorbidities, health-related QOL, and oxygen dependence were independent predictors of physical activity in patients with COPD. Our study sample included a high proportion of people in both the intervention and control groups with severe and very severe COPD by GOLD staging. Persons with this level of illness are more likely to be severely compromised functionally because of the oppressive symptom load of dyspnea and fatigue and are more prone to frequent, often immobilizing exacerbations of their illnesses.1 It is possible that these people may be less responsive to an adherence intervention than would persons with better lung health and functional capacity. Short-term improvement in accelerometer activity from baseline correlated negatively with self-reported activity at baseline. This finding may be the result of a regression toward the mean of people who report exercising less at baseline. This group might be expected to show greater improvement with an intervention that supports increasing their exercise levels. Short-term improvement in self-reported activity from baseline correlated negatively with age and CCI score, meaning that people who were older and had more comorbidities reported a lesser improvement in daily exercise. Long-term data show general weaker, nonsignificant correlations compared with short-term measures. This may reflect an inadequate “dose” of the intervention. The intervention was inexpensive and readily integrated into the clinical responsibilities of study staff. Equipment used, such as pedometers and exercise bands, were readily available, and minimal time was needed to instruct participants in their use. Likewise, although the initial development of the exercise handbook did require considerable time in terms of literature review and preparation, the updating and selected tailoring of the handbook regarding exercise venues and the like for individual participants was not prohibitive. Study Limitations This study was limited by a lack of sufficient power to detect change in the primary outcome, daily activity; a number of design issues, including lack of a sham control group; selection of subjects, the intervention itself, and measurement issues. We powered the study on a quantitative measure of daily activity, because previous studies have shown that motion sensors measure exercise duration better than self-report, which is constrained by memory and other factors. We also assumed, based on our previous work, that persistence of exercise duration after pulmonary rehabilitation would be great enough to be reflected in daily activity with this highly sedentary group.27 This assumption may have contributed to a type 2 error. The likelihood of a type 2 error is further increased by lower than anticipated enrollment. We enrolled around 50 subjects in each group, about 10 subjects short of the anticipated 60 subjects per group determined by our power analysis. Another factor that may explain the lack of differences between the intervention and control groups in the accelerometer measure of daily activity was the finding that the RT3 data had a high signal-to-noise ratio that swamped any differences in daily activity. This finding is evidenced by large day-to-day variations in VMU, further contributing to low power of the RT3 measurement of daily activity. We suspect that an arduous side-by-side comparison of the performance characteristics of the TriTrac-R3D and the RT3 might have shown that the TriTrac-R3D had a better signal-to-noise ratio, which would help explain why this device was able to detect subtle differences in daily activity in people who were exercising for greater durations. This was not done, because preventive maintenance and recalibration of the TriTrac-R3D units in our possession were no longer available and the TriTrac-R3D could no longer be purchased. The inclusion of an attention control or sham treatment group in addition to the intervention and usual care groups might have helped control for the fact that study participants were not blinded to their group randomizations and received considerable contact from study staff. Most studies of this nature do not include an attention control group because of the fundamental difficulty of selecting an appropriate contact intervention that makes sense, yet provides minimal meaningless burden to subjects. Another limitation was the finding of baseline differences between intervention and control groups with respect to the primary outcomes, including daily activity, 6-minute walk, and self-reported exercise, although only the latter was statistically significant. In addition, more subjects in the control group had very severe COPD by GOLD staging.1 Randomization that included some matching would have ensured that the groups were comparable on the 3 major outcomes and GOLD staging. The sample was composed predominantly of men; therefore, the findings should be generalized to women with caution. After randomization, there was an unexpected loss of participants due to COPD exacerbation and other causes, thus contributing to a loss of statistical power. Another potential limitation was the actual adherence intervention, and the question of whether the intervention was strong enough to effect and maintain behavior change. Although flexible and tailored to meet individual needs, the timing of the intervention may have occurred too late in the process of exercise or activity adoption to provide optimal benefit for behavioral practice and persistence. Likewise, although specific components of the home visit (safety assessment, home exercise facilitation) and phone calls (assessment of exercise, problem-solving, encouragement) were semistructured across subjects, perhaps more inclusive scripting of the phone intervention should have been provided; in this regard, the intervention might have been more effective at maintaining behavioral change if a standard format using motivational interviewing had been used. Clinical Relevance and Recommendations for Further Study Exercise interventionists in rehabilitation care practice in varied settings that are not limited to cardiac and pulmonary rehabilitation; these therapists share a keen interest in improving outcomes. The exercise-based therapeutics that they administer are similar to the dosing of medicinal treatments in that beneficial outcomes do not occur in the absence of adherence to the therapeutic regimen. Our findings of improved adherence in self-reported exercise and concomitant persistence in exercise tolerance gains over a period of 12 weeks after a standard pulmonary rehabilitation program suggest that incorporation of a relatively simple, highly feasible, inexpensive program for imbedding exercise into the lives of participants can appreciably augment the benefit of these programs and increase the potential for long-term benefit for some patients. Further study might address the following: (1) the potential benefit of integrating this or similar adherence interventions in the body of the pulmonary rehabilitation program rather than after its completion, (2) the inclusion of specific self-management strategies to prevent disease exacerbations that contribute to nonadherence, and (3) the development of exercise venues with limited professional staffing supported by the rehabilitation program for graduates of exercise-based programs. Studies addressing these issues might be particularly attractive to capitation-based health care organizations providing existing preventive health programs in weight management, nutrition, and nicotine dependency. Conclusions The benefits of the adherence intervention that included individualized coaching and a home visit provided only limited short-term improvement in exercise capacity and self-reported maintenance of exercise after pulmonary rehabilitation in this highly sedentary group of patients with chronic lung disease. No long-term benefits were evident. We recommend caution in the use of the RT3 accelerometer to measure free-living daily activity because of the unacceptably high signal-to-noise ratio evident in this sedentary population. Continued research will be necessary to identify more effective activity measures and to better structure pulmonary rehabilitation adherence interventions to optimize benefits over time. Suppliers Acknowledgment The views expressed in this article are those of the authors and do not necessarily represent the views of the U.S. Department of Veterans Affairs. Appendix 1. Overview of Exercise Adherence Intervention | Phase 1. Transitioning to home exercise (weeks 1−4): Home Visit | | | •Establish a home exercise program with emphasis on walking–Develop skill in using resistance training equipment –Develop expertise in using the digiwalker and exercise monitoring strategies –Obtain at least 1 piece of exercise equipment for home use (optional) •Develop a realistic plan for community-based exercise | | | Phase 2. Making exercise a habit (weeks 5−8): Weekly Telephone Follow-Up | | | •Carry out a regular program of exercise, at least 20 minutes, 4 days a week •Carry out self-monitoring and recording of exercise sessions •Develop problem-solving skills to prevent exercise lapses •Participate in at least 1 activity outside the home per week that involves exercise | | | Phase 3. Overcoming exercise barriers (weeks 5−12): Weekly Telephone Follow-Up | | | •Continued self-monitoring and recording of exercise sessions •Identify barriers to exercise and actively problem-solve solutions as they occur •Participate in exercise sessions with 1 or more other people (optional) •Identify new or continuing individual benefits of the exercise program | | | | |
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a Primary Care and Specialty Medicine Service, Department of Veterans Affairs Puget Sound Health Care System, Seattle, WA b University of Washington School of Nursing, Seattle, WA c VA Health Services Research and Development, VA Puget Sound Health Care System, Seattle, WA d Department of Veterans Affairs Puget Sound Health Care System, Rehabilitation Care Service and Departments of Rehabilitation Medicine and Epidemiology, University of Washington, Seattle, WA.  Reprint requests to Bonnie G. Steele, PhD, VA Puget Sound Medical Center (S-111-B), 1660 Columbian Way S, Seattle, WA 98108
Supported by the Department of Veterans Affairs, Veterans Health Administration, Health Services Research and Development Service (grant no. NRI 98-194) and the University of Washington School of Nursing (research and intramural funding grant). No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the authors are associated. PII: S0003-9993(07)01746-7 doi:10.1016/j.apmr.2007.11.003 © 2008 American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved. | |
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