Pulmonary rehabilitation for interstitial lung disease.

BACKGROUND

Interstitial lung disease (ILD) is characterised by reduced functional capacity, dyspnoea and exercise-induced hypoxia. Pulmonary rehabilitation is often used to improve symptoms, health-related quality of life and functional status in other chronic lung conditions. There is accumulating evidence for comparable effects of pulmonary rehabilitation in people with ILD. However, further information is needed to clarify the long-term benefit and to strengthen the rationale for pulmonary rehabilitation to be incorporated into standard clinical management of people with ILD. This review updates the results reported in 2014.

OBJECTIVES

To determine whether pulmonary rehabilitation in people with ILD has beneficial effects on exercise capacity, symptoms, quality of life and survival compared with no pulmonary rehabilitation in people with ILD. To assess the safety of pulmonary rehabilitation in people with ILD.

SEARCH METHODS

We searched CENTRAL, MEDLINE (Ovid), Embase (Ovid), CINAHL (EBSCO) and PEDro from inception to April 2020. We searched the reference lists of relevant studies, international clinical trial registries and respiratory conference abstracts to look for qualifying studies.

SELECTION CRITERIA

We included randomised controlled trials and quasi-randomised controlled trials in which pulmonary rehabilitation was compared with no pulmonary rehabilitation or with other therapy in people with ILD of any origin.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, extracted data and assessed risk of bias. We contacted study authors to request missing data and information regarding adverse effects. We specified a priori subgroup analyses for participants with idiopathic pulmonary fibrosis (IPF) and participants with severe lung disease (low diffusing capacity or desaturation during exercise). There were insufficient data to perform the prespecified subgroup analysis for type of exercise training modality.

MAIN RESULTS

For this update, we included an additional 12 studies resulting in a total of 21 studies. We included 16 studies in the meta-analysis (356 participants undertook pulmonary rehabilitation and 319 were control participants). The mean age of participants ranged from 36 to 72 years and included people with ILD of varying aetiology, sarcoidosis or IPF (with mean transfer factor of carbon dioxide (TLCO) % predicted ranging from 37% to 63%). Most pulmonary rehabilitation programmes were conducted in an outpatient setting, with a small number conducted in home-based, inpatient or tele-rehabilitation settings. The duration of pulmonary rehabilitation ranged from three to 48 weeks. There was a moderate risk of bias due to the absence of outcome assessor blinding and intention-to-treat analyses and the inadequate reporting of randomisation and allocation procedures in 60% of the studies. Pulmonary rehabilitation probably improves the six-minute walk distance (6MWD) with mean difference (MD) of 40.07 metres, 95% confidence interval (CI) 32.70 to 47.44; 585 participants; moderate-certainty evidence). There may be improvements in peak workload (MD 9.04 watts, 95% CI 6.07 to 12.0; 159 participants; low-certainty evidence), peak oxygen consumption (MD 1.28 mL/kg/minute, 95% CI 0.51 to 2.05; 94 participants; low-certainty evidence) and maximum ventilation (MD 7.21 L/minute, 95% CI 4.10 to 10.32; 94 participants; low-certainty evidence). In the subgroup of participants with IPF, there were comparable improvements in 6MWD (MD 37.25 metres, 95% CI 26.16 to 48.33; 278 participants; moderate-certainty evidence), peak workload (MD 9.94 watts, 95% CI 6.39 to 13.49; low-certainty evidence), VO (oxygen uptake) peak (MD 1.45 mL/kg/minute, 95% CI 0.51 to 2.40; low-certainty evidence) and maximum ventilation (MD 9.80 L/minute, 95% CI 6.06 to 13.53; 62 participants; low-certainty evidence). The effect of pulmonary rehabilitation on maximum heart rate was uncertain. Pulmonary rehabilitation may reduce dyspnoea in participants with ILD (standardised mean difference (SMD) -0.36, 95% CI -0.58 to -0.14; 348 participants; low-certainty evidence) and in the IPF subgroup (SMD -0.41, 95% CI -0.74 to -0.09; 155 participants; low-certainty evidence). Pulmonary rehabilitation probably improves health-related quality of life: there were improvements in all four domains of the Chronic Respiratory Disease Questionnaire (CRQ) and the St George's Respiratory Questionnaire (SGRQ) for participants with ILD and for the subgroup of people with IPF. The improvement in SGRQ Total score was -9.29 for participants with ILD (95% CI -11.06 to -7.52; 478 participants; moderate-certainty evidence) and -7.91 for participants with IPF (95% CI -10.55 to -5.26; 194 participants; moderate-certainty evidence). Five studies reported longer-term outcomes, with improvements in exercise capacity, dyspnoea and health-related quality of life still evident six to 12 months following the intervention period (6MWD: MD 32.43, 95% CI 15.58 to 49.28; 297 participants; moderate-certainty evidence; dyspnoea: MD -0.29, 95% CI -0.49 to -0.10; 335 participants; SGRQ Total score: MD -4.93, 95% CI -7.81 to -2.06; 240 participants; low-certainty evidence). In the subgroup of participants with IPF, there were improvements at six to 12 months following the intervention for dyspnoea and SGRQ Impact score. The effect of pulmonary rehabilitation on survival at long-term follow-up is uncertain. There were insufficient data to allow examination of the impact of disease severity or exercise training modality. Ten studies provided information on adverse events; however, there were no adverse events reported during rehabilitation. Four studies reported the death of one pulmonary rehabilitation participant; however, all four studies indicated this death was unrelated to the intervention received.

AUTHORS' CONCLUSIONS: Pulmonary rehabilitation can be performed safely in people with ILD. Pulmonary rehabilitation probably improves functional exercise capacity, dyspnoea and quality of life in the short term, with benefits also probable in IPF. Improvements in functional exercise capacity, dyspnoea and quality of life were sustained longer term. Dyspnoea and quality of life may be sustained in people with IPF. The certainty of evidence was low to moderate, due to inadequate reporting of methods, the lack of outcome assessment blinding and heterogeneity in some results. Further well-designed randomised trials are needed to determine the optimal exercise prescription, and to investigate ways to promote longer-lasting improvements, particularly for people with IPF.