Characteristics of patients with COPD and nocturnal oxygen desaturation

Background: Significant nocturnal oxygen desaturation occurs in about 40% of patients with severe COPD. In a prevalence study, we could not identify any predictor of this phenomenon. Given the high prevalence and the uncertain management of nocturnal desaturation, we undertook the INOX trial, an international randomized trial of nocturnal oxygen in COPD. Objective: To describe the baseline characteristics of patients randomized in the INOX trial, and to compare them with those obtained in a prevalence study of nocturnal desaturation in COPD conducted as a preliminary step to the trial. Methods: As of January 1 2014, we screened 588 patients; 221 with desaturation (> 30% of oximetry recording time with SpO 2 < 90%) were identified and 190 randomized in the trial. Baseline characteristics included demographics, medication, lung function and nocturnal oximetry parameters. The same characteristics of 49 patients with COPD identified as nocturnal desaturators in the prevalence study were used for comparison. Results: The INOX patients (125 men, 66%) were aged 69 years (± SD: 8), had an FEV 1 of 41% predicted (± 20), a room air PaO 2 of 67 mmHg ± 7, a PaCO 2 of 42 mmHg ± 6, a body mass index of 27 kg/m 2 ± 6, and were all ex-smokers for at least 6 months (pack•years: 63 ± 40). We found no difference between the INOX patients and those of the pilot study with the exception of inhaled medication and nocturnal desaturation indices. Conclusion: Nocturnal desaturation is highly prevalent in severe COPD. This supports the importance of the INOX trial that investigates whether this phenomenon should be treated.