Home oxygen therapy reduces risk of hospitalisation in patients with chronic obstructive pulmonary disease: a population-based retrospective cohort study, 2005-2012.

Abstract

This study evaluated the effect of home oxygen therapy (HOT) on hospital admissions in chronic obstructive pulmonary disease (COPD) patients. Using nationwide health insurance claims from 2002-2012, we conducted a longitudinal population-based retrospective cohort study. Individuals who were aged 40 years or above and newly diagnosed with COPD in 2005. The primary outcome was total number of hospitalisations during the study period. Participants were matched using HOT propensity scores and were stratified by respiratory impairment (grade 1: FEV1 ≤25% or PaO2 ≤55 mm Hg; grade 2: FEV1 ≤30% or PaO2 56-60 mm Hg; grade 3: FEV1 ≤40% or PaO2 61-65 mm Hg; 'no grade': FEV1 or PaO2 unknown), then a negative binomial regression analysis was performed for each group. Of the 36,761 COPD patients included in our study, 1330 (3.6%) received HOT. In a multivariate analysis of grade 1 patients performed before propensity score matching, the adjusted relative risk of hospitalisation for patients who did not receive HOT was 1.27 (95% CI 1.01 to 1.60). In a multivariate analysis of grade 1 patients performed after matching, the adjusted relative risk for patients who did not receive HOT was 1.65 (95% CI 1.25 to 2.18). In grade 2 or grade 3 patients, no statistical difference in hospital admission risk was detected. In the 'no grade' group of patients, HOT was associated with an increased risk of hospitalisation. HOT reduces the risk of hospital admission in COPD patients with severe hypoxaemia. However, apart from these patients, HOT use is not associated with hospital admissions.