Snoring Survivors: the impact of obstructive sleep apnoea and continuous positive airway pressure use on in-hospital mortality, length of stay and costs among patients hospitalised with acute cardiovascular disease - A retrospective analysis of 2016-2019 National Inpatient Sample Data.

Background: The routine administration of supplemental oxygen to non-hypoxic patients with acute myocardial infarction (AMI) has been abandoned for lack of mortality benefit. However, the benefits of continuous positive airway pressure (CPAP) use in patients hospitalised with acute cardiovascular disease and concomitant obstructive sleep apnoea (OSA) remain to be elucidated.

Methods: In this retrospective case-control analysis, using 10th International Classification of Diseases, Clinical Modification (ICD-10) codes, we searched the 2016-2019 Nationwide Inpatient Sample for patients diagnosed with unstable angina (UA), AMI, acute decompensated heart failure (ADHF) and atrial fibrillation with rapid ventricular response (AFRVR), who also carried a diagnosis of OSA. We identified in-hospital CPAP use with ICD-10-Procedure Coding System codes. In-hospital death, length of stay (LOS) and hospital charges were compared between patients with and without OSA, and between OSA patients with and without CPAP use.

Results: Our sample included 2 959 991 patients, of which 1.5% were diagnosed with UA, 30.3% with AMI, 37.5% with ADHF and 45.8% with AFRVR. OSA was present in 12.3%. Patients with OSA were more likely to be younger, male, smokers, obese and have chronic obstructive pulmonary disease, renal failure and heart failure (p<0.001 for all). Patients with OSA had significantly lower in-hospital mortality (aOR 0.71, 95% CI (0.7 to 0.73)). Among patients with OSA, CPAP use significantly increased the odds of in-hospital death (aOR 1.51, 95% CI (1.44 to 1.60)), LOS (adjusted mean difference of 1.49 days, 95% CI (1.43 to 1.55)) and hospital charges (adjusted mean difference of US$1168, 95% CI (273 to 2062)).

Conclusion: Our study showed that patients with recognised OSA hospitalised for AMI, ADHF and AFRVR had significantly lower mortality regardless of CPAP use, while CPAP treatment among these patients was associated with significantly higher in-hospital mortality and resource utilisation. The routine use of CPAP during acute cardiovascular encounters could neutralise the impact of chronic intermittent ischaemic preconditioning.