Background: In the outpatient setting, untreated obstructive sleep apnea (OSA) is associated with myriad adverse clinical outcomes including myocardial infarction, heart failure, arrhythmias, and cerebrovascular disease.  However, little is known about the impact of treated versus untreated OSA on short-term outcomes in patients hospitalized with acute illness. We propose that the recurrent hypopnea and apnea that characterize OSA may lead to a higher risk of adverse outcomes in hospitalized patients who are likely to be simultaneously exposed to other physiologic stressors.

Methods: We retrospectively reviewed records of 852 hospitalized patients with a diagnosis of OSA to determine if inpatient CPAP usage was associated with adverse outcomes. Patients were classified as “compliant” with CPAP if they used the device for at least 4 hours each night. 

Results: Patients were 58% male with a mean age of 60 years old and an average hospital length of stay of 6 days. 52% of patients were categorized as compliant with CPAP during hospitalization. Multivariate regression analysis revealed that non-compliance with CPAP was associated with a nearly 40% increased risk of in-hospital myocardial infarction [adjusted odds ratio (95% CI) = 0.593 (0.372-0.946) p=0.028]. No statistically significant association was found between CPAP compliance and arrhythmias, heart failure, respiratory failure, cerebrovascular event, or death.

Conclusions: Among hospitalized patients with a diagnosis of OSA, noncompliance with CPAP was associated with an almost 40% increase in risk of MI during hospitalization. Additional research is needed to validate this finding and clarify the factors that underlie this association.