Background: Interstitial lung disease (ILD) is characterised by exertional dyspnoea, exercise limitation and reduced quality of life. The role of exercise training in this diverse patient group is unclear. The aims of this study were to establish the safety of exercise training in ILD; its effects on exercise capacity, dyspnoea and quality of life; and whether patients with idiopathic pulmonary fibrosis (IPF) had similar responses to those with other types of ILD.
Methods: Fifty-seven subjects with ILD (thirty-four IPF) were randomised to receive eight weeks of supervised exercise training or weekly telephone support. The six-minute walk distance (6MWD), incremental exercise test, modified Medical Research Council (MRC) dyspnoea score and Chronic Respiratory Disease questionnaire (CRDQ) were performed at baseline, following intervention and at six months.
Results: Eighty percent of subjects completed the exercise program and no adverse events were recorded. The 6MWD increased following training (mean difference to control 35 m, 95% confidence interval (CI) 6-64 m). A significant reduction in MRC score was observed (0.7 points, 95% CI 0.1-1.3) along with improvements in dyspnoea (p = 0.04) and fatigue (p < 0.01) on the CRDQ. There was no change in VO2peak; however exercise training reduced heart rate at maximum workload (p = 0.01). There were no significant differences in response between those with and without IPF. After six months there were no differences between the training and control group for any outcome variable.
Conclusions: Exercise training in ILD improves exercise capacity and symptoms in patients with ILD, however these benefits are not sustained six months following intervention.
Editor's Comment. Pulmonary rehabilitation recommendations, using data from studies on patients with chronic obstructive pulmonary disease (COPD), have been extrapolated to a variety of lung diseases. This study is welcomed as the first randomized trial of exercise training in patients with interstitial lung diseases. Its value is somewhat reduced by the heterogeneous patient population, but it does answer some important questions. The first is that the exercise benefit seen in these patients falls short of that anticipated in COPD and the 35-m 6MWD difference between exercise and control groups falls short of being clinically meaningful, despite its statistical significance. The fact that even this is not sustained at 6 months is likely a consequence of multiple contributing factors-the small initial improvement itself and the impact of (unspecified in the article) treatment are likely important, but the foremost indicator of poor durability of effect was a 220-ml mean fall in the forced vital capacity observed over the 6-month period, suggesting a disease course far more rapidly progressive than is seen in COPD.
This study suggests that COPD-based recommendations should not be generalized to patients with ILDs and that exercise training in these patients should be critically appraised by looking at the effort (and expense of time and money) on the one hand and the small benefit on the other. At the very least, this study permits a data-based assessment of the anticipated benefits of a palliative intervention in patients with potentially progressive diseases. -SK