Visca D, et al. - Researchers investigated how health-related quality of life (HRQOL) in patients with interstitial lung disease with isolated exertional hypoxia is influenced by ambulatory oxygen. According to findings, ambulatory oxygen seemed to be related to improved HRQOL and could afford an effective intervention for these patients who have few therapeutic options.

Methods

• A prospective, open-label, mixed-method, crossover randomised controlled clinical trial, named AmbOx, was carried out.
• This trial was conducted at three centres for interstitial lung disease in the UK.
• Patients aged 18 years or older, having fibrotic interstitial lung disease, without hypoxia at rest but having a fall in transcutaneous arterial oxygen saturation to 88% or less on a screening visit 6-min walk test (6MWT), and having self-reported stable respiratory symptoms in the previous 2 weeks were considered eligible.
• Randomization (1:1) of participants to either oxygen treatment or no oxygen treatment for 2 weeks, followed by crossover for another 2 weeks, was done via a computer-generated sequence of treatments randomly permuted in blocks of constant size (fixed size of ten).
• The change in total score on the King's Brief Interstitial Lung Disease questionnaire (K-BILD) after 2 weeks on oxygen vs 2 weeks of no treatment was assessed (primary outcome) by intention to treat.
• The analysis was done using general linear models with treatment sequence as a fixed effect.
• Using semi-structured topic-guided interviews in a subgroup of participants, patient views were determined.

Results

• Forty-one patients were randomly assigned to oxygen first and 43 to no oxygen between Sept 10, 2014, and Oct 5, 2016; overall patients were 84.
• The trial was completed by 76 participants.
• Significant improvements in total K-BILD scores (mean 55·5 [SD 13·8] on oxygen vs 51·8 [13·6] on no oxygen, mean difference adjusted for order of treatment 3·7 [95% CI 1·8 to 5·6]; p<0·0001), and scores in breathlessness and activity (mean difference 8·6 [95% CI 4·7 to 12·5]; p<0·0001) and chest symptoms (7·6 [1·9 to 13·2]; p=0·009) subdomains were observed in association with ambulatory oxygen vs no oxygen.
• However, no significant impact on the psychological subdomain was evident (2·4 [–0·6 to 5·5]; p=0·12).
• Upper respiratory tract infections (three in the oxygen group and one in the no-treatment group) were documented as the most common adverse events.
• Five serious adverse events were reported, including the occurrence of two deaths (one in each group), but none were considered to be related to treatment.