(1171) Chronic Hypoxemia Is Associated With Reduced Positive Pressure Ventilation Usage in COPD-OSA Overlap

Introduction: Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) have been termed COPD-OSA overlap syndrome when present as comorbidities. Using the National Inpatient Sample, we previously found that surprisingly, during hospitalization for acute exacerbation of COPD (AECOPD), COPD-OSA overlap is associated with lower mortality compared to patients with COPD alone. We hypothesized that this association may be partly driven by mechanisms of hypoxic preconditioning. To examine this relationship, this study evaluated the association between chronic hypoxemia and utilization of positive pressure ventilation.

Methods: The National Inpatient Sample was used to examine utilization of non-invasive positive pressure ventilation (NIPPV) and mechanical ventilation (MV) in patients with COPD-OSA overlap hospitalized for AECOPD. ICD codes were used to identify NIPPV and MV utilization, as well as diagnoses like chronic hypoxemia. A matched pairs design was used to stratify patients by presence of OSA, and comorbidity burden was compared using the Charleston Comorbidity Index. Multivariable logistic regression modeling was used to compare NIPPV and MV usage and control for diagnoses that affect utilization.

Results: 43,628 patients with chronic hypoxemia were identified, and this condition was associated with reduced usage of NIPPV (OR 0.782; 95% CI 0.745 – 0.820), of MV for less than 96 hours (OR 0.227; 95% CI 0.192 – 0.267), and of MV for greater than 96 hours (OR 0.254; 95% CI 0.198 – 0.327). This association was unique compared to other diagnoses controlled for using regression modeling, namely OSA, chronic hypercapnia, myocardial infarction, heart failure, asthma, and pneumonia. OSA was associated with increased usage of NIPPV (OR 2.128; 95% CI 2.099 – 2.157) and MV for less than 96 hours (OR 1.131; 95% CI 1.098 – 1.165) but did not have a statistically significant difference in usage of MV greater than 96 hours (OR 1.008; 95% CI 0.967 – 1.050).

Conclusions: In the context of hospitalization for AECOPD in patients with COPD-OSA overlap, a diagnosis of chronic hypoxemia was associated with reduced utilization of NIPPV and MV. Chronic hypoxemia may be protective in the acute setting as mechanisms of hypoxic preconditioning may make patients less likely to require positive pressure support.