Background: Pulmonary rehabilitation (PR) improves performance in the 6-min walk test (6MWT) in a subset of patients with fibrotic idiopathic interstitial pneumonia (f-IIP); however, a large proportion of patients does not respond to PR.
Aim: To investigate the effects of a PR program on cardiorespiratory responses during a 6MWT and to identify the characteristics of patients who do not show improved performance after PR.
Design: An observational study.
Setting: Patients were recruited from the Competence Centre for Rare Pulmonary Diseases at Lille University Hospital, France and completed an 8-week home-based PR program.
Population: A total of 19 patients with f-IIP; 12 with idiopathic pulmonary fibrosis (IPF) and 7 with fibrotic non-specific interstitial pneumonia.
Methods: Patients underwent spirometry and completed a 6MWT before and after an 8-week PR program. Gas exchange, heart rate, and pulse O2 saturation were measured continuously during the 6MWT. Quality of life, dyspnea, and anxiety/depression were assessed using the Short-Form 36 (SF-36), the baseline/transition dyspnea index (BDI/TDI), and the Hospital Anxiety and Depression Scale (HADS) questionnaires.
Results: Patients who did and did not improve the distance walked in the 6MWT by at least 30 m after PR were classified as responders (N.=9) and non-responders (N.=10), respectively. O2 uptake, ventilation rate, and distance covered during the 6MWT were significantly improved only in the responder group (P<0.05). Changes in SF-36, BDI/TDI, and HADS scores did not differ significantly between responders and non-responders. The non-responder group contained significantly more patients with IPF (P<0.05) and experienced greater arterial oxygen desaturation during the 6MWT compared with the responder group.
Conclusions: Failure to improve performance in the 6MWT after PR was associated with a diagnosis of IPF, non-improvement in gas exchange, and greater arterial oxygen desaturation.
Clinical rehabilitation impact: Most f-IIP patients who did not respond to PR were diagnosed with IPF and displayed greater hypoxemia during exercise. Clinical practitioners should seek to determine why patients fail to improve exercise performance after PR and propose an alternative exercise regimen to these patients.