Lung; Disease, Fibroid (Chronic) Clinical Trial
Official title:
Randomized, Controlled Crossover Trial to Evaluate the Effects of Ambulatory Oxygen on Health Status in Patients With Fibrotic Lung Disease (FLD).
The main aim of this project is to establish whether ambulatory oxygen in patients with fibrotic ILD whose oxygen saturation falls ≤ 88% on a 6MWT, leads to a significant improvement in health status. The core of the project will be a four week randomised, crossover controlled trial of ambulatory oxygen used during daily activities. The optimal Oxygen flow rate is determined by titration at screening visit and administered during activity for a two-week period, compared to two weeks off oxygen.
The planned non-commercial study is a randomised, controlled crossover trial of ambulatory
oxygen against no ambulatory oxygen over a four week period (two weeks on ambulatory oxygen
and two weeks on air, with no portable devices), to evaluate the effects of ambulatory oxygen
on health status in patients with ILD. A short crossover study in this context has many
advantages, since ambulatory oxygen has immediate effect, with no wash-out period needed
after use. The primary outcome of the study will be the change in health status, as measured
by the K-BILD questionnaire (Thorax 2012 67: 804-810).
At the start of the trial, the effects of ambulatory oxygen on 6 Minute Walk Test (6MWT)
parameters will be evaluated on oxygen and on air-filled canisters, with the patient blind to
the contents of the canister, to assess whether oxygen-induced improvements in 6MWT
parameters can predict its effectiveness in day to day life. The 6MWT is a well established
and highly reproducible test validated in ILD patients, with significant prognostic
implications.
The study design does not include a placebo arm because:
1. The intervention is a combination of possible benefits from oxygen and the disadvantage
of canister weight. These cannot be separated. Placebo control is impossible because
there is no means of providing placebo weight. Attempts to control solely for oxygen use
without taking canister weight into account are clinically meaningless. In a recent
COPD, chronic obstructive pulmonary disease study, cylinder weight was reported as a
barrier to use by 93% of study participants.
2. A positive result against an air-filled canister arm would be clinically
uninterpretable. This is a study design in which the 'placebo' would be actively harmful
to study participants. Carriage of an air-filled cylinder would be expected to lead to
earlier desaturation and reduced exercise tolerance. Such a design would not inform the
real life comparison between oxygen plus cylinder and no intervention.
3. All this aside, blinding is legally impossible (UK health and safety regulations require
that oxygen cylinders for home use must be clearly labelled).
It should also be stressed that objective measures of change are evaluated as secondary
end-points: the investigators expect to explore correlations between these variables and the
primary end-point to exclude the possibility that an observed treatment benefit on the
primary end-point might be confounded by a placebo effect.
A more in depth qualitative assessment of the impact of ambulatory oxygen will be undertaken
via a semi-structured interview, in a subset of 20 patients, to investigate patients' and
their carers' personal perspective on how the ambulatory oxygen has affected their day to day
life. The interview will be conducted within 2 weeks of the end of treatment visit. Patients
from the Royal Brompton Hospital site will be approached by the researcher at the end of
treatment visit and asked if they will participate in the qualitative assessment. If the
patient agrees a date will be agreed for the patient to be interviewed at a venue convenient
to them (usually the patient's home).
During the interviews a semi-structured topic guide will address practical barriers to
optimal oxygen usage, practical, social and psychological difficulties encountered, concerned
about dependency, and views on the information required prior to ambulatory oxygen
prescription. The interviews will also explore patients' (and carers') experience of
participating in the trial. Notes will be written after each interview to aid reflective
analytical processes. Individual feed back on how the system and the service could be
improved will assess how the needs of patients and their future involvement can be
incorporated into the design of more patients and their future involvement can be
incorporated into the design of more patients centred devices.
Qualitative interview analysis: Interviews will be transcribed verbatim. Interview
transcripts will be analysed thematically using a framework approach. Atlas/ti computer
software (http://atlasti.com) will be used to manage and index the data prior to charting,
mapping and interpretation.
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