Association between self-reported moderate to vigorous physical activity and the rate of outpatient treated COPD exacerbations: retrospective cohort study

INTRODUCTION: Little has been published regarding the relationship between physical activity (PA) and outpatient treated, mild to moderate acute exacerbation of chronic obstructive pulmonary disease exacerbations (AECOPD). The purpose of this study was to determine the association between self-reported PA and outpatient treated AECOPD over 2 years using real-world data obtained from existing electronic medical records (EMRs). METHODS: We included 44 896 patients with a chronic obstructive pulmonary disease diagnosis from the EMR in this retrospective cohort study. Moderate to vigorous PA was measured via patient self-report, obtained during routine clinical care; patients were classified as inactive (0 min/week), insufficiently active (1–149 min/week) or active (≥150 min/week). AECOPDs were measured using both encounter and prescription fill (antibiotics and/or oral steroids) data. We used Poisson regression models to compare the unadjusted and adjusted rates of outpatient treated AECOPD over 2 years across the PA categories. RESULTS: In adjusted models, the 2-year AECOPD incidence rate ratio (IRR) was not different between the inactive and insufficiently inactive groups (IRR 0.98, 95% CI 0.96 to 1.01) and only marginally meaningful lower for the active group (IRR 0.97, 95% CI 0.95 to 0.98). Sensitivity analyses of patients meeting or not meeting obstructive criteria produced similar results with generally weak or non-significant associations. CONCLUSION: The lack of an association between PA and AECOPD contrasts with previous published findings of a strong relationship between moderate to vigorous PA and hospitalisations for severe AECOPD. This difference could partially be attributed to the imprecision of our measurements for both the exposure and outcome.