Baseline characteristics of all patients with follow-up (N = 138).

<p>*Mean (standard deviation)</p><p>^$ Proportion (95% confidence interval)</p><p>Abbreviations: A-a gradient alveolar to arterial gradient, AHI apnea hypopnea index, BMI body mass index, COPD chronic obstructive pulmonary disease, FEV1 forced expiratory volume in 1 second, FVC forced vital capacity, OSA obstructive sleep apnea, OHS the obesity hypoventilation syndrome, PaO₂ arterial partial pressure of oxygen, PaCO₂ arterial partial pressure of carbon dioxide, mmHg millimeter of mercury, 95%CI 95% confidence interval</p><p>Baseline characteristics of all patients with follow-up (N = 138).