Effect of respiratory muscle training and Pulmonary rehabilitation on exercise capacity in patients with ILD – A prospective quasi-experimental study

Background: Interstitial lung diseases(ILDs) are associated with skeletal muscle dysfunction, worsening exercise capacity and poor health related quality of life(HRQoL). The clinical relevance of respiratory muscle training(RMT) as part of pulmonary rehabilitation(PR) in ILD patients largely remains unknown with limited research evidence.
Objective: To evaluate effect of PR on exercise capacity in patients with ILD and study its relation with disease severity.
Methods: Twenty-five patients diagnosed as ILD(clinical, radiological or histopathological basis ATS/ERS criteria) and willing for PR, were enrolled in this prospective observational study between 2016-2017 after informed consent. All cases were subjected to supervised exercise training thrice weekly for 8 weeks, tailored as per their capacity, in addition to pharmacologic and supportive treatment. Outcome measures including six minute walk test(6MWT), respiratory muscle pressure(RMP), dyspnea(Borg scale), and spirometry were evaluated at baseline, eight weeks and six months following completion of program and recorded in a pre-structured Proforma.
Results: The mean age of patients was 63.28±10.88 years with majority being non-smokers(88%) and females(60%). There was significant improvement in mean 6MWT distance(p=0.02), inspiratory muscle pressure(p=0.047) and dyspnoea after exercise training when compared at 8 weeks from the baseline. The change in spirometry values was non-significant. The improvement in outcome parameters was transient with no significant difference from baseline at 6 months after stopping PR.
Conclusion: Exercise training significantly improves the respiratory muscle strength and functional capacity in patients with ILD. Larger studies with multidimensional analysis are required to investigate the promising outcome of pulmonary rehabilitation in such patients.