The effect of supplemental oxygen in obesity hypoventilation syndrome

Rationale: Supplemental oxygen is commonly prescribed to patients with obesity hypoventilation syndrome (OHS). However, there is paucity of data regarding its efficacy and safety. Objectives: To assess the medium-term treatment efficacy of adding supplemental oxygen therapy to commonly prescribed treatment modalities in OHS. Methods: In this post-hoc analysis of a previous randomized controlled trial, we studied 302 sequentially screened OHS patients who were assigned to positive airway pressure (PAP) or lifestyle modification. Outcomes at two months included arterial blood gases, symptoms, quality of life, blood pressure, polysomnography, spirometry, six-minute walk distance, and hospital resource utilization. Statistical analysis comparing patients with and without oxygen therapy in the two treatment groups was performed using an intention-to-treat analysis. Results: In the PAP group, those receiving supplemental oxygen had a lower clinical and quality of life improvement than in the group of patients with PAP alone. However, supplemental oxygen led to greater reduction of systolic blood pressure and emergency room visits. In the lifestyle modification group, supplemental oxygen increased compensatory metabolic alkalosis without any significant benefit. Conclusion: Oxygen therapy added to PAP produced mixed results that were insufficient to consider it, globally, as beneficial or deleterious. In the lifestyle modification group, supplemental oxygen therapy did not result in any significant benefits at medium-term. Long-term studies examining outcomes such as healthcare resource utilization, incident cardiovascular morbidity and mortality are necessary.