Repeating pulmonary rehabilitation: Prevalence, predictors and outcomes

The effect of inspiratory muscle training and detraining on the respiratory metaboreflex

NEW FINDINGS

What is the central question of this study? Is the attenuation of the respiratory muscle metaboreflex preserved after detraining? What is the main finding and its importance? Inspiratory muscle training increased respiratory muscle strength and attenuated the respiratory muscle metaboreflex as evident by lower heart rate and blood pressure. After 5 weeks of no inspiratory muscle training (detraining), respiratory muscle strength was still elevated and the metaboreflex was still attenuated. The benefits of inspiratory muscle training persist after cessation of training, and attenuation of the respiratory metaboreflex follows changes in respiratory muscle strength.

ABSTRACT

Respiratory muscle training (RMT) improves respiratory muscle (RM) strength and attenuates the RM metaboreflex. However, the time course of muscle function loss after the absence of training or 'detraining' is less known and some evidence suggest the respiratory muscles atrophy faster than other muscles. We sought to determine the RM metaboreflex in response to 5 weeks of RMT and 5 weeks of detraining. An experimental group (2F, 6M; 26 ± 4years) completed 5 weeks of RMT and tibialis anterior (TA) training (each 5 days/week at 50% of maximal inspiratory pressure (MIP) and 50% maximal isometric force, respectively) followed by 5 weeks of no training (detraining) while a control group (1F, 7M; 24 ± 1years) underwent no intervention. Prior to training (PRE), post-training (POST) and post-detraining (DETR), all participants underwent a loaded breathing task (LBT) to failure (60% MIP) while heart rate and mean arterial blood pressure (MAP) were measured. Five weeks of training increased RM (18 ± 9%, P < 0.001) and TA (+34 ± 19%, P < 0.001) strength and both remained elevated after 5 weeks of detraining (MIP-POST vs. MIP-DETR: 154 ± 31 vs. 153 ± 28 cmH2O, respectively, P = 0.853; TA-POST vs. TA-DETR: 86 ± 19 vs. 85 ± 16 N, respectively, P = 0.982). However, the rise in MAP during LBT was attenuated POST (-11 ± 17%, P = 0.003) and DETR (-9 ± 9%, P = 0.007) during the iso-time LBT. The control group had no change in MIP (P = 0.33), TA strength (P = 0.385), or iso-time MAP (P = 0.867) during LBT across all time points. In conclusion, RM and TA have similar temporal strength gains and the attenuation of the respiratory muscle metaboreflex remains after 5 weeks of detraining.

Efficacy of Repeating Pulmonary Rehabilitation in People with COPD: A Systematic Review

Background

Pulmonary rehabilitation is an effective intervention for people with chronic obstructive pulmonary disease (COPD). People with COPD undertake repeat programs, but synthesis of evidence regarding such practice has not been undertaken. The aim of this systematic review was to establish the effects of repeating pulmonary rehabilitation subsequent to an initial program in people with COPD.

Methods

Studies where participants with COPD undertook >1 pulmonary rehabilitation program were included, incorporating RCT (randomized controlled trial) and non-randomized studies. Electronic database searches were undertaken. Two authors independently undertook study identification, data extraction and risk of bias assessment. The primary outcome was health-related quality of life (HRQoL); secondary outcomes were exercise capacity, hospitalizations and exacerbations, adherence, mortality and adverse events. Narrative synthesis was undertaken for clinically heterogeneous trials. Data from RCTs and non-randomized studies were not combined for analysis.

Results

Ten included studies (2 RCTs) involved 907 participants with COPD (n=653 had undertaken >1 program). The majority of studies were at high risk of bias. One RCT (n=33) reported no difference in HRQol after a repeat program vs usual care following exacerbation (Chronic Respiratory Disease Questionnaire dyspnea domain score MD 0.4, 95% CI -0.5 to 3). In stable patients, clinically important and statistically significant improvements in HRQoL and exercise capacity were reported after repeat programs, but of a smaller magnitude than initial programs. There was evidence for reductions in exacerbations and hospitalizations, and shorter hospital length of stay for patients who repeated a program twice in 12 months compared to those who repeated once. No data for mortality or adverse events were available.

Conclusion

This systematic review provides limited evidence for benefits of repeating pulmonary rehabilitation in people with COPD, including improved HRQoL and exercise capacity, and reduced hospitalizations. However, most studies have high risk of bias, which reduces the certainty of these conclusions.

Study Registration

PROSPERO (CRD42020215093).

Trajectories of COPD patients' response to repeated pulmonary rehabilitation programs

BACKGROUND AND OBJECTIVE

Pulmonary rehabilitation (PR) is essential in the management of chronic obstructive pulmonary disease (COPD), but the long-term effects and the outcomes of repeated programs especially in non-responders remain to be clarified. The aim of this study is to evaluate the long-term effect of PR 12 months after and the effect of repeated PR depending on the patient's response to the first PR.

METHODS

This is a single center retrospective analysis of COPD patients admitted to two or three PR programs between January 2012 and December 2017, using the 6-min walking distance (6MWD) to determine the functional response to PR.

RESULTS

One hundred ninety patients completed PR twice and 62 completed PR three times with 10-14 months delay between programs. The effect of the first PR program (PR1) on 6MWD was mostly lost after one year. The 6MWD change after the second PR program (PR2) was smaller than after PR1 (+65 ± 30 m post-PR1, +44 ± 20 m post-PR2; p = 0.001). Out of the 149 responders post-PR1, 44 (30%) became non-responders post-PR2. Out of the 41 non-responders post-PR1, 23 (56%) became responders post-PR2. Patients with long term oxygen therapy and severe exercise dyspnea were most likely to remain non-responders to repeated PR.

CONCLUSION

This study showed that most of the 6MWD improvement following PR disappears over 12 months and emphasized the clinical relevance of repeating PR including for non-responders to initial PR. However, some patients did not respond systematically to PR and may require specific PR modalities to improve their functional status.

"Willingness to Pay": The Value Attributed to Program Location by Pulmonary Rehabilitation Participants

The "contingent valuation" method is used to quantify the value of services not available in traditional markets, by assessing the monetary value an individual ascribes to the benefit provided by an intervention. The aim of this study was to determine preferences for home or center-based pulmonary rehabilitation for participants with chronic obstructive pulmonary disease (COPD) using the "willingness to pay" (WTP) approach, the most widely used technique to elicit strengths of individual preferences. This is a secondary analysis of a randomized controlled equivalence trial comparing center-based and home-based pulmonary rehabilitation. At their final session, participants were asked to nominate the maximum that they would be willing to pay to undertake home-based pulmonary rehabilitation in preference to a center-based program. Regression analyses were used to investigate relationships between participant features and WTP values. Data were available for 141/163 eligible study participants (mean age 69 [SD 10] years, n = 82 female). In order to undertake home-based pulmonary rehabilitation in preference to a conventional center-based program, participants were willing to pay was mean $AUD176 (SD 255) (median $83 [IQR 0 to 244]). No significant difference for WTP values was observed between groups (p = 0.98). A WTP value above zero was related to home ownership (odds ratio [OR] 2.95, p = 0.02) and worse baseline SF-36 physical component score (OR 0.94, p = 0.02). This preliminary evidence for WTP in the context of pulmonary rehabilitation indicated the need for further exploration of preferences for treatment location in people with COPD to inform new models of service delivery.

Why do people with chronic obstructive pulmonary disease repeat pulmonary rehabilitation? Perspectives of patients and health professionals

Many people with chronic obstructive pulmonary disease (COPD) undertake pulmonary rehabilitation more than once. This study examined patient experiences and health professional perspectives regarding repeating pulmonary rehabilitation. Participants were 14 patients with COPD and 15 health professionals. Patients had undertaken pulmonary rehabilitation at a tertiary hospital; health professionals were doctors, physiotherapists, and nurses. Semi-structured interviews were conducted, and data were analyzed using thematic analysis. Patients described improved fitness and better breathing after repeating pulmonary rehabilitation; however, some also reported that repeating required confronting their disease progression. Improved confidence and motivation were an important outcome of repeating. Although most participants had attended community-based exercise classes, they valued the greater intensity of exercise and closer supervision that came with repeating pulmonary rehabilitation. Health professionals reported referring patients to repeat pulmonary rehabilitation if they had worsening functional capacity, an exacerbation, or hospitalization. There was no agreement regarding the optimal time for repeating and many would only re-refer if the patient demonstrated motivation to attend. In conclusion, patients with COPD reported many symptomatic benefits from repeating pulmonary rehabilitation and gained confidence from a supervised program. There was no agreement between health professionals regarding the optimal time to repeat pulmonary rehabilitation.

Magnitude of exercise capacity and quality of life improvement following repeat pulmonary rehabilitation in patients with COPD

Background

Maintenance and repeated pulmonary rehabilitation programs (PRPs) for patients with COPD have attempted to prolong PRP benefits beyond 12–24 months. However, there is limited evidence as to the magnitude of benefit or the ideal interval between repeating the program under “real-world” conditions in which patients are referred based on clinical necessity. Therefore, we reviewed the effects of repeating PRP in a physician-referred cohort of patients with COPD.

Methods

A total of 141 individuals with COPD completed PRP twice and 35 completed PRP three times over a 12-year period. We used linear mixed-effects models to quantify the magnitude and change in 6-minute walk distance (6MWD), St George’s Respiratory Questionnaire (SGRQ), and Hospital Anxiety and Depression Scale (HADS) for each PRP. One-way analysis of variance with Tukey’s post hoc analysis compared the effects of different time intervals on 6MWD, SGRQ, and HADS between PRPs.

Results

Despite 39 mL/year average decrease in forced expiratory volume in 1 second, overall 6MWD improved following each PRP (PRP1=58 m, P<0.0001; PRP2=42 m, P<0.0001; PRP3=32 m, P<0.003). Mean SGRQ decreased after PRP1 (−7.0 units; P<0.001) and PRP2 (−4.9 units; P<0.0001) but not after PRP3 (−3.2 units; P=0.10). HADS decreased after PRP1 (−1.9 units; P<0.0001) and PRP2 (−1.7 units; P=0.0001) but not after PRP3 (−0.4 units; P=0.63).

Conclusion

In physician-referred patients who underwent repeat PRP as clinically required, there were clear benefits in functional exercise capacity following each repeat PRP, which was not affected by the time interval between PRPs. Health-related quality of life and mood improved after the first two PRPs, but not after a third.

Time to adapt exercise training regimens in pulmonary rehabilitation--a review of the literature

Exercise intolerance, exertional dyspnea, reduced health-related quality of life, and acute exacerbations are features characteristic of chronic obstructive pulmonary disease (COPD). Patients with a primary diagnosis of COPD often report comorbidities and other secondary manifestations, which diversifies the clinical presentation. Pulmonary rehabilitation that includes whole body exercise training is a critical part of management, and core programs involve endurance and resistance training for the upper and lower limbs. Improvement in maximal and submaximal exercise capacity, dyspnea, fatigue, health-related quality of life, and psychological symptoms are outcomes associated with exercise training in pulmonary rehabilitation, irrespective of the clinical state in which it is commenced. There may be benefits for the health care system as well as the individual patient, with fewer exacerbations and subsequent hospitalization reported with exercise training. The varying clinical profile of COPD may direct the need for modification to traditional training strategies for some patients. Interval training, one-legged cycling (partitioning) and non-linear periodized training appear to be equally or more effective than continuous training. Inspiratory muscle training may have a role as an adjunct to whole body training in selected patients. The benefits of balance training are also emerging. Strategies to ensure that health enhancing behaviors are adopted and maintained are essential. These may include training for an extended duration, alternative environments to undertake the initial program, maintenance programs following initial exercise training, program repetition, and incorporation of approaches to address behavioral change. This may be complemented by methods designed to maximize uptake and completion of a pulmonary rehabilitation program.