Condition category
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status
Results overdue

Plain English Summary

Not provided at time of registration

Trial website

Contact information



Primary contact

Dr Yves Lacasse


Contact details

Centre de Pneumologie
Hôpital Laval
2725 chemin Ste-Foy
G1V 4G5
+1 418 656 4747

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title


CANOX trial

Study hypothesis

Long-term oxygen therapy (LTOT) is the only component of the management of chronic obstructive pulmonary disease (COPD) that improves survival in patients with severe daytime hypoxemia. In Canada, LTOT is usually provided by a stationary oxygen concentrator and is recommended to be used for at least 15 - 18 hours a day. Several studies have demonstrated a deterioration in arterial blood gas pressures and oxygen saturation during sleep in patients with COPD. Sleep-related oxygen desaturation often occurs in patients not qualifying for LTOT. The suggestion has been made that the natural progression of COPD to its end stages of chronic pulmonary hypertension, severe hypoxemia, right heart failure, and death is dependent upon the severity of desaturation occurring during sleep. This is an attractive hypothesis and is supported by the fact that hypoxemic episodes during sleep are accompanied by substantial increases in pulmonary arterial pressure and often by important cardiac arrhythmias. Supplemental nocturnal oxygen alleviates both the acute increases in pulmonary arterial pressure and the cardiac arrhythmias.

It has been suggested that, over the long run, nocturnal oxygen therapy (N-O2) may halt the progression of long-standing cor pulmonale and prolong survival. Probably due to the fact that the recommendations of scientific societies regarding the indications for and use of N-O2 in COPD not qualifying for conventional LTOT are presently imprecise, a number of patients are currently treated with N-O2 although the beneficial effects of this therapy have not been confirmed.

In patients with Chronic Obstructive Pulmonary Disease (COPD) not qualifying for Long Term Oxygen Therapy (LTOT) but who present significant nocturnal arterial oxygen desaturation, nocturnal oxygen therapy provided for a period of 3 years is effective in decreasing mortality or delaying the requirement for LTOT, and is cost-effective and favourably compares to other medical interventions

Ethics approval

Pending as of 20/10/2006.

Study design

A 3-year, multicentre, placebo-controlled, randomised trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet


Chronic obstructive pulmonary disease (COPD)


1. Nocturnal oxygen therapy group: N-O2 will be delivered overnight to allow the oxygen saturation to be greater than 90%
2. Placebo: the patients allocated in the control group will receive room air delivered by sham concentrator

Intervention type



Not Specified

Drug names

Nocturnal oxygen therapy

Primary outcome measure

The primary outcomes of this trial are mortality from all cause or requirement for LTOT (composite outcome).

Secondary outcome measures

1. Quality of life and utility measures
2. Costs from a societal perspective
3. Compliance with oxygen therapy

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Patients with a diagnosis of COPD supported by an history of past or current smoking and obstructive disease with forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) less than 60%
2. Presence of mild-to-moderate daytime hypoxemia with a daytime partial pressure of oxygen in arterial blood (paO2) in the range of 56 - 69 mmHg
3. Patients fulfilling our definition of nocturnal oxygen desaturation: greater than or equal to 30% of the recording time with transcutaneous arterial oxygen saturation less than 90% on two consecutive recordings

Participant type


Age group

Not Specified


Not Specified

Target number of participants


Participant exclusion criteria

1. Patients fulfilling the usual criteria for continuous oxygen therapy (CONT-O2) at study entry:
1.1. PaO2 less than or equal to 55 mmHg, or
1.2. PaO2 less than or equal to 59 mmHg with clinical evidence of at least one of the following:
1.2.1. Pulmonary hypertension
1.2.2. Right ventricular hypertrophy
1.2.3. Cor pulmonale
1.2.4. Haematocrit greater than or equal to 55%
2. Patients with sleep apnea (defined by an apnoea/hypopnoea index of greater than or equal to 15 events/hour
3. Patients currently on nocturnal oxygen therapy (N-O2)
4. Patients with known left heart or congenital heart diseases, interstitial lung diseases, bronchiectasis as the main cause of their obstructive disease, lung carcinoma or other severe diseases that could influence survival (hepatic cirrhosis and chronic renal failure)

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Centre de Pneumologie
G1V 4G5

Sponsor information


Laval University (Canada)

Sponsor details

Cité Universitaire
C.P. 2208
G1K 7P4

Sponsor type




Funder type

Research organisation

Funder name

Canadian Institutes of Health Research (CIHR) (Canada) - (ref: MOP-36329)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes