The trajectory of chronic obstructive pulmonary disease (COPD) is frequently punctuated by exacerbations, defined as episodes of acute worsening of respiratory symptoms that result in additional therapy.1,2 Acute exacerbations of COPD (AECOPD) account for more than 70% of all COPD-related costs3 and are mainly responsible for patients’ clinical deterioration.1 It is known that AECOPD result in significant decline in muscle strength, functional capacity and lung function, which further impairs patients’ health-related quality of life (HRQoL) and increases their susceptibility to more exacerbations, hospitalisations and death.1,2,4,5 Therefore, treatment goals for patients with AECOPD are to minimise the negative impact of these events and prevent their recurrence.1

Pulmonary rehabilitation (PR) is a well-established intervention for the management of patients with stable COPD.1,6 It has been shown to: (i) improve exercise capacity, functional capacity, muscle strength and HRQoL; (ii) reduce symptoms, hospitalisations and unscheduled healthcare visits; and (iii) enhance self-management and self-efficacy.6 Given these benefits it would seem reasonable to consider PR as a management strategy for AECOPD.7 However, studies assessing the role of PR during AECOPD have shown controversial results;1,8 this is probably related to the settings in which the PR programmes have been conducted and the disease severity of patients included. Most studies have been conducted in hospitalised patients,3,9 who present more severe exacerbations and/or more severe underlying disease than those managed on an outpatient setting.1 Although it is recognised that more than 80% of all AECOPD are managed on an outpatient basis,1 only a few studies have conducted PR programmes on an outpatient setting.10–13 Additionally, those studies did not start their intervention at the onset of the AECOPD but shortly after the AECOPD,10,11 included patients with AECOPD who have previously been hospitalised,12,13 and have found significant results in different outcomes (e.g., exercise capacity,10,12 HRQoL,10–12 and re-exacerbations13). Thus, the potential role of PR programmes during AECOPD in patients managed on an outpatient basis is not yet clarified. Moreover, outpatient basis includes community-based PR (i.e., PR programmes nearby patients’ homes), which may be a promising approach to overcoming the shortcomings of poor access and transport to PR, especially in patients with AECOPD, but has hardly been investigated.14,15

Therefore, this pilot study aimed to explore the feasibility of conducting a community-based PR programme during AECOPD and assess its effects on patients’ symptoms, muscle strength, functionality, impact of the disease, peripheral oxygen saturation and hospitalizations.

Thirty-five outpatients with AECOPD were referred for possible inclusion in the study. From these, three were excluded due to the presence of sequels from a cerebrovascular accident that impaired her/his ability to perform the assessments (n=1), suffering from Parkinson's disease (n=1) and interstitial lung disease (n=1). Thus, 32 patients were invited to participate in the study and allocated to either the EG or CG. Three patients in the EG (1 due to incompatibility of schedules and 2 no reason given) and six in the CG (2 due to incompatibility of schedules and 4 no reason given) dropped out of the study. Therefore, 23 patients (19 males, 67.3±8.0 years, forced expiratory volume in 1s 57.2±23.9%predicted), 12 in the EG and 11 in the CG, were included (Fig. 2).

Figure 2.

Flow diagram of participants through the study.

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There were no significant differences between completers and dropouts in terms of age (p=0.551) and gender (p=0.303). Participants’ characteristics are summarised in Table 1. No significant differences were observed between groups at baseline (p>0.05).

All patients in the EG completed the full PR programme (i.e., 6/6 sessions, attendance=100%) and no adverse events were reported.

After the community-based PR programme, significant improvements were found in the EG in symptoms of dyspnoea at rest (Pre 3 [0.5; 3.8] vs. Post 1 [0.0; 2.8], p=0.008), respiratory rate (Pre 24 [20.5; 27] vs. Post 20.5 [18; 23.5], p=0.004), SpO2 (Pre 94 [89.3; 96] vs. Post 96 [94.3; 96], p=0.031), quadriceps muscle strength (Pre 21 [19.7; 27.2] vs. Post 25 [22.4; 28.8], p=0.012) and CAT score (Pre 23 [19.3; 24.8] vs. Post 14.5 [6.3; 19.5], p=0.008). No differences were found in the remaining outcome measures (p>0.05). The CG did not present any significant differences after the intervention (Fig. 3).

Figure 3.

Median difference and interquartile range Pre/Post the intervention per group in: (a) the modified British Medical Research Council dyspnoea questionnaire (mMRC); (b) heart rate (beats per minute, bpm); (c) respiratory rate (cycles per minute, cpm); (d) peripheral oxygen saturation (SpO2); (e) symptoms of dyspnoea at rest in the modified Borg scale (mBorg); (f) symptoms of fatigue at rest in the modified Borg scale (mBorg); (g) quadriceps muscle strength; (h) the 5-repetition sit-to-stand test (5-STS); and (i) the COPD assessment test (CAT) total score.

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In the between groups comparison, the EG showed significant improvements when compared to the CG in respiratory rate (EG −3.5 [−4; −0.5] vs. CG 2 [0; 4], p=0.015), quadriceps muscle strength (EG 3.1 [1.9; 7.2] vs. CG −0.5 [−2.8; 1.4], p=0.021) and CAT (EG −6 [−15; −4.0] vs. CG 0 [−8; 3], p=0.013). No additional differences were found (Fig. 3).

There was a significantly higher number of patients improving above the MCID of CAT in the EG than in the CG (EG 11 vs. CG 5, p=0.027). No differences were found for the remaining outcome measures.

None of the patients, either in the EG or in the CG, needed to be hospitalised or made unscheduled use of the healthcare services during the 3 weeks of intervention.

This quasi-experimental pilot study showed that community-based PR might be effective during mild-to-moderate AECOPD. Significant improvements were found in symptoms, vital signs, quadriceps muscle strength and impact of the disease and no adverse events were reported. However, patients were allowed to choose their group allocation.

Symptoms are key features of COPD41 and have been considered important outcomes of PR during exacerbations.3,42 In this study, after PR there was a significant decrease in dyspnoea levels at rest and most patients improved above the MCID in the mMRC and mBorg. Nevertheless, although positive improvements have been found for the EG, there were no significant differences in between group comparisons, which is probably related with the small sample size. Furthermore, no significant improvements have been found for fatigue, possibly because of the relatively low baseline fatigue scores found in our patients. These results must be carefully interpreted as dyspnoea and fatigue are multifactorial symptoms that should be described considered as both patients’ subjective perception and a performance component, and the mMRC and the mBorg are unidimensional tools that measure only a specific moment and were applied at rest.43,44 Therefore, these instruments might have failed to capture dyspnoea and the overall impact of fatigue. Multidimensional and disease-specific scales should be used in future studies to allow a multifactorial assessment of these symptoms and contribute to a better understanding of their behaviour during a PR programme in AECOPD.45 Moreover, the available MCIDs for the mMRC and the mBorg have been established for patients with AECOPD receiving standard of care.32 Future studies exploring MCIDs for patients with AECOPD undergoing PR are needed to better understand the added value of this intervention.

Despite the importance of assessing symptoms individually, it is their combination that impacts on patients’ HRQoL,9,41 hence a comprehensive symptom assessment is necessary.1 CAT is a short, simple, multidimensional and easy to administer questionnaire that has been developed to cover the most burdensome symptoms and limitations perceived by patients.46 Recent literature has shown that CAT is responsive to treatment47,48 and provides relevant prognostic information,49 therefore its use to assess PR during AECOPD has been advocated.9,47 In this study, the significant improvements and number of patients improving above the MCID show that CAT is sensitive to changes and supports its routine use in clinical practice.

Vital signs and SpO2 are measures previously used in PR programmes conducted in hospitalised patients with AECOPD and improvements, or patterns of improvement, have been reported,50–53 suggesting that PR is a safe approach during AECOPD. This pilot study corroborates these findings for PR implemented in the community. No adverse events were reported; however, a systematic assessment of adverse events was not conducted. Future studies should carefully assess occurrence of adverse events and the need for unscheduled healthcare visits during and after each session of PR to establish effectiveness and safeness of this intervention.

Quadriceps muscle weakness is a well-known systemic consequence of COPD1 that affects patients’ HRQoL and survival.54 During AECOPD there is a more accentuated decline in muscle function, resulting in long-term losses on functional capacity.55 This study, similarly to previous research, has shown that PR can prevent muscle dysfunction by improving quadriceps muscle strength during AECOPD,13,54,56,57 thus becoming a key intervention to manage peripheral muscle weakness and prevent further clinical decline.

It has been recognised that functionality, a vital outcome for patients’ daily life, is severely impaired during AECOPD.41,58 In this study, no differences were found in patients’ functionality after PR. This finding is likely to be due to the ceiling effect observed in the 5-STS and not to the ineffectiveness of the intervention. At baseline, patients already presented a good functional status as they were performing the test below the cut off for risk of falling (i.e., 12s),59 so with little room for improvement. Given the importance of this outcome, further research on the most appropriate outcome measure to assess functionality in patients with AECOPD is needed.

This study presents some limitations that need to be acknowledged. Firstly, patients were not randomised and assessors were not blinded. However, efforts were made to minimise the risk of bias by ensuring that patients characteristics at baseline were similar and implementing a well-defined assessment protocol and standardised intervention. Secondly, physical activity levels were not monitored during the AECOPD and it is possible that patients willing to participate in the PR programme were also more willing to be physically active. Nevertheless, baseline physical activity levels were no different between the groups. We registered however, a higher drop-out rate in the control group, probably due to patients’ lack of motivation60 and lack of perceived benefit of their participation.15 It is known that patients who have chosen not to attend PR are also less likely to participate in respiratory-related research61 and, thus, more likely to drop out. Third, pharmacological treatment was not standardised, but rather prescribed according to pulmonologists’ best judgement of patients’ clinical condition. Although no differences have been found regarding medication on baseline assessment, it must be acknowledged that different combinations of drugs might have influenced patients’ recovery. Fourth, exercise capacity, which is a key outcome of PR, was not assessed in this study due to lack of space to perform commonly used field exercise capacity tests (e.g., six-minute walk test and incremental shuttle walk test) at patients’ home, although aerobic training was performed. Future studies should explore the effects of community-based PR during AECOPD on patients’ exercise capacity using alternative field-tests. Since informative and promising results were obtained, there is now the need to adjust the outcome measures used and personalise PR to patients’ needs, in a randomised controlled trial.

Community-based PR seems feasible and offers promise to provide timely and effective management of patients with mild-to-moderate AECOPD. The addition of PR to standard of care resulted in improvements in respiratory rate, symptoms, quadriceps muscle strength and impact of the disease, parameters usually associated with an increased risk of AECOPD recurrence and poor prognosis,37,62,63 and no adverse events reported. Future research should focus on randomised studies with larger samples to clarify the role of community-based PR during AECOPD.

This work was funded by Programa Operacional de Competitividade e Internacionalização – POCI, through Fundo Europeu de Desenvolvimento Regional – FEDER (POCI-01-0145-FEDER-007628), Fundação para a Ciência e Tecnologia (PTDC/DTP-PIC/2284/2014 and PTDC/SAU-SER/28806/2017) and under the project UID/BIM/04501/2013 and UID/BIM/04501/2019.

The authors report no conflict of interest.