The comprehensive study by Carrieri-Kohlman et al1 provides 10 months of follow-up data of an earlier report comparing the benefits of 0, 4, and 24 exercise training sessions combined with a dyspnea self-management program (DM) for 2 months in patients with stable chronic obstructive pulmonary disease (COPD).2 The DM program included individualized education, recommended home walking and completion of an daily exercise log, as well as biweekly telephone calls by a nurse. Both DM and exercise training can be considered as components of a comprehensive pulmonary rehabilitation program. The primary outcome of the study was the intensity of dyspnea as measured by 2 different approaches-questionnaires related to activities of daily living and patient-reported ratings during walking tests. The exercise tests included the 6-minute walking distance (6MW) as well as incremental and endurance treadmill exercise. The major finding was that dyspnea ratings were reduced with the combination of DM and 24 training sessions over the follow-up period as measured during incremental treadmill exercise compared with the other two groups. However, this benefit was not observed with the 6MW, endurance treadmill exercise, or the dyspnea questionnaires.
This clinical trial was challenging for both subjects and investigators. Testing was performed at baseline and every 2 months for 1 year. At these visits, patients had to answer questions about breathlessness, health status, and health resource utilization; perform spirometry; and rate dyspnea before and at the end of the 6MW test and during incremental as well as endurance treadmill exercise. These sequential and serial tests certainly required a high level of motivation and effort for both subjects and staff. Although the slope of dyspnea/time during endurance treadmill exercise did not show a benefit beyond 2 months, the testing protocol required that subjects perform the endurance test following the incremental test once their vital signs had returned to baseline (at least 30 minutes). It is possible that any leg "fatigue" experienced by the patients could have influenced the results. Concurrent ratings of leg discomfort along with dyspnea may have addressed this possibility.3
It is unclear why the DM-24 exercise training sessions group did not show greater relief of dyspnea based on questionnaires related to activities of daily living [Chronic Respiratory Questionnaire (CRQ) and Transition Dyspnea Index] compared with the other two groups. Previous studies have clearly demonstrated improvements in dyspnea as measured on these clinical instruments following pulmonary rehabilitation.4,5 In fact, the group who received dyspnea self-management alone (ie, no exercise training) exhibited dramatic improvements in the dyspnea component of the CRQ compared with baseline that exceeded the changes observed in the DM-24 trainings sessions group. I agree with the statement of the authors in the discussion that these changes presumably reflect the efficacy of the dyspnea self-management program. However, in a meta-analysis, Warsi et al6 reported that self-management educational programs, in general, have resulted in only small to moderate benefits for select chronic disorders. Accordingly, a prospective study comparing DM with a control group (eg, educational program on strategies to enhance memory or some other task) would be required to address the specific benefits of dyspnea self-management.
Importantly, the results provide further support that exercise is good for our patients with COPD. Pitta et al7 recently documented the sedentary lifestyle of patients with COPD by monitoring their daily activities using a triaxial accelerometer. On average, the 50 patients with COPD (FEV1 = 43% +/- 18% predicted) spent about 80% of a 12-hour day either standing or sitting! Thus, any physical activity should contribute to both physiologic and/or perceptual improvements, and more frequent exercise training sessions are clearly better. Possible mechanisms whereby exercise training activities might relieve dyspnea include a reduction in ventilatory demand as mediated by physiologic training responses and/or enhanced mechanical efficiency as well as psychologic factors.
The authors should be congratulated for enrolling a large cohort of subjects to study the role of dyspnea self-management along with a few versus many exercise training sessions. However, in clinical practice, the plaguing question remains, "Why don't more of our patients participate in pulmonary rehabilitation programs?" Despite my best efforts, only about 50% of patients for whom I recommend a pulmonary rehabilitation actually participate in the program. The patients offer both creative and interesting reasons for their unwillingness to join a program. Yet, the scientific literature is clear that exercise training is the "key" ingredient to pulmonary rehabilitation, and that there are numerous benefits to the patient who is willing to exercise.4 Perhaps our patients with respiratory disease are merely representative of the general population who choose not to expend extra energy riding a cycle ergometer or walking on a treadmill "that goes nowhere." For those patients who experience angina or a myocardial infarction, physician referral to cardiac rehabilitation program is automatic and patient participation is widely accepted. Yet, for those patients who seek medical attention because of "shortness of breath" or have experienced an exacerbation of COPD, overall enthusiasm for pulmonary rehabilitation program is quite variable.
How should the medical community engage our patients with symptomatic respiratory disease to start exercising at home and/or to join a pulmonary rehabilitation program? (1) Should we advertise our programs in the newspaper and on the radio? (2) Should we explore exercise opportunities for our patients that are fun and inspirational? (3) Should we modify cycle ergometry into a spinning class with an instructor and music? (4) Should we show a video of a marathon race or people hiking to inspire our patients while they are walking on the treadmill? I suggest that our efforts need to be more ingenious to interest/cajole our dyspneic patients to join/continue pulmonary rehabilitation. As an example, Steele et al8 observed that a tailored adherence intervention (written materials, a home visit, and 12 weekly phone calls) after completion of pulmonary rehabilitation maintained short-term activity and exercise improvement in the patients compared with no scheduled follow-up.
Over the past decade, investigators have developed the scientific evidence that has advanced our knowledge of the multiple benefits of pulmonary rehabilitation. For the next decade, I propose that we focus our efforts to further explore the social-behavioral-psychologic factors that influence an individual's decision whether or not to exercise. Isn't that the next step?
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