Severe physical inactivity in chronic obstructive pulmonary disease: changes in systemic inflammation after pulmonary rehabilitation – a pilot study

Abstract

Background The purpose was to investigate whether severe physical inactivity (SPI) is associated with altered levels of common inflammatory markers as compared to higher Physical activity levels (PALs), and whether pulmonary rehabilitation would reduce the levels of systemic inflammation in SPI in patients with COPD. Methods This prospective, cohort study was conducted in four rehabilitation centers in Region Zealand, Denmark. We included patients with COPD referred for 7-12 weeks of pulmonary rehabilitation (2-hours of exercise therapy and education twice weekly). We measured b-eosinophils, p-fibrinogen, p-CRP, s-IL-6, s-CD 163, nasal lavage-IL-8, and daily physical activity, using a validated activity monitor, SenseWear®, at baseline and after rehabilitation. SPI was defined as PAL <1.4.Results In total, 31 of 57 patients were SPI at baseline, and seven (23%) of these patients improved to non-SPI after pulmonary rehabilitation. We observed no significant differences in the primary endpoint i.e. change in systemic inflammation between patients who remained SPI at both time pints vs. patients who improved PAL from SPI at baseline to non-SPI at follow-up. At baseline, SPI was associated with significantly higher p-fibrinogen levels (p=0.04) than non-SPI, but no other differences were observed between SPI and non-SPI Conclusion In a cohort of patients with COPD attending pulmonary rehabilitation, we could not demonstrate any differences or changes in systemic inflammation or PAL following rehabilitation between patients with SPI and non-SPI. This might be a true negative finding or due to a high pro-inflammatory drive in all patients regardless of SPI status or study limitations such as suboptimal levels of rehabilitation intensity and SPI cut-off level. The study was registered at ClinicalTrials.gov (NCT01700296), https://register.clinicaltrials.gov. Registered in November 2012.