Study parameters
| Parameters | Baseline | Follow-up |
| Before 6MWT | ||
| Demographics, smoking history, diagnosis, basis for the diagnosis, year of diagnosis | X | |
| Comorbidities, medications, resting oxygen saturation | X | |
| Pulmonary function (FEV1, FVC, DLCO) | X | |
| LTOT, dose and duration | X | X |
| GAP/GOLD stage | X | |
| KBILD | X | X |
| CAT | X | X |
| MRC score | X | X |
| 6MWT with COB and DODS | X | |
| After 6MWT | ||
| Patient preferences for COB or DODS (“Which system do you prefer?”) | X | |
| Comfort measured by a Likert scale | X | X |
| Reliability measured by a Likert scale | X | X |
| Qualitative interviews about patients’ view on AOT with COB/DODS | X | |
| Registration of adverse events | X | X |
AOT, ambulatory oxygen therapy; CAT, Chronic Obstructive Pulmonary Disease Assessment Test; COB, continuous oxygen with bottles; DLCO, diffusing capacity of the lungs for carbon monoxide; DODS, demand oxygen delivery system; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; GAP, gender-age-physiology; GOLD, Global Initiative for Chronic Obstructive Lung Disease; KBILD, The King’s Brief Interstitial Lung Disease Questionnaire; LTOT, long-term oxygen therapy; MRC, Medical Research Council; 6MWT, 6-minute walk test.