RESUMO
RATIONALE: Hypoxemia in obese patients is likely to be associated with a high prevalence of sleep-disordered breathing. Supplemental oxygen is commonly used to treat chronic hypoxemia but carries some risk in obese individuals due to unrecognized comorbid obstructive sleep apnea (OSA) and obesity hypoventilation syndrome (OHS). OBJECTIVES: The first step in the estimation of this risk is to determine the prevalence of OSA and OHS in obese individuals with chronic, awake hypoxemia. METHODS: A single-center retrospective cohort study was performed to assess the prevalence and severity of OSA and OHS among obese individuals with hypoxemia. One hundred eighty-four individuals underwent arterial blood gas testing and polysomnography. One hundred fifty-eight of these individuals also had spirometry. MEASUREMENTS AND MAIN RESULTS: The prevalence of OSA was 80%, and the prevalence of OHS was 51%. Chronic obstructive pulmonary disease (COPD) was confirmed by spirometry in 49% of the cohort, and OSA was found in 69% of those individuals. The severity of hypoxemia in this cohort was not statistically related to COPD, OSA, or OHS. CONCLUSIONS: OSA and OHS are highly prevalent in obese patients with chronic awake hypoxemia, and OSA frequently coexists with COPD. Evaluation of chronic, awake hypoxemia solely based on arterial blood gas measurements and pulmonary function testing is not sufficient to identify OSA and OHS. Further diagnostic sleep testing should be performed to identify those who could benefit from alternative therapies and to avoid potential harm from treatment with supplemental oxygen alone.