Nocturnal oxygen has no effect on survival of COPD patients: NEJM

Delhi: Nocturnal oxygen neither has a positive or negative impact on survival or progression to long-term oxygen therapy in COPD patients, suggests a recent study in the New England Journal of Medicine.

Long-term oxygen therapy helps in improving survival in chronic obstructive pulmonary disease (COPD) patients with chronic severe day time hypoxemia. However, the effectiveness of oxygen therapy for the management of isolated nocturnal hypoxemia is not known. So, the researchers determined whether the administration of nocturnal oxygen for a period of 3 to 4 years would decrease mortality or the worsening of disease such that patients meet current specifications for long-term oxygen therapy, in patients with COPD having nocturnal arterial oxygen desaturation without qualifying for long-term oxygen therapy. 

For the purpose, the researchers designed a double-blind, placebo-controlled, randomized trial. In which, patients with an oxygen saturation of less than 90% for at least 30% of the recording time on nocturnal oximetry were assigned to receive either nocturnal oxygen or ambient air from a sham concentrator (placebo) in a 1:1 ratio. 

The primary outcome was a composite of death from any cause or a requirement for long-term oxygen therapy as defined by the Nocturnal Oxygen Therapy Trial (NOTT) criteria in the intention-to-treat population.

Recruitment had to be stopped prematurely because of recruitment and retention difficulties after 243 patients, of a projected 600, had undergone randomization at 28 centers.

The researchers found that at 3 years of follow-up, 39.0% of the patients assigned to nocturnal oxygen (48 of 123) and 42.0% of those assigned to placebo (50 of 119) met the NOTT-defined criteria for long-term oxygen therapy or had died. 

"Our underpowered trial did not show evidence of an effect of nocturnal oxygen therapy on survival or progression to long-term oxygen therapy in patients with COPD with isolated nocturnal oxygen desaturation," concluded the authors. "Because enrollment in the trial was stopped before we had reached our proposed sample size, the trial was underpowered."