Sleep apnea is associated with reduced in-hospital mortality in patients admitted for acute heart disease

<bold>Introduction:</bold> Sleep apnea (SA) is an independent risk factor for cardiovascular diseases. The impact of SA on the outcome of patients hospitalized for cardiovascular diseases is controversial. Recent studies indicated fewer fatal cardiac events associated with SA in a setting where comorbidities may play an important role. <bold>Aims:</bold> The aim of our study was to further investigate the in-hospital mortality of patients hospitalized for acute cardiovascular diseases with or without SA. <bold>Methods:</bold> Data were extracted from a Swiss-wide hospitalization database. All patients hospitalized for acute heart disease were extracted. Among those patients, all patients with a co-diagnosis of SA were extracted together with a 1:1 matched control population without SA. The impact of SA together with other comorbidities was investigated using competing risks survival analysis. <bold>Results:</bold> Between 2010 and 2020, 744,455 hospitalizations due to acute heart disease were monitored in Switzerland among which 21,904 had SA. Patients with SA had a longer length of stay, were more often rehospitalized, had more comorbidities but had a lower in-hospital mortality compared to controls (HR: 0.40 [95% CI: 0.35 to 0.45]; p<0.001). Several comorbidities significantly interacted with SA. Obesity and hypertension were independently associated with a lower in-hospital mortality in both SA and non- SA. Other comorbidities were associated with an increased in-hospital mortality. Shock and acute myocardial infarction were more frequent and significantly more harmful in non-SA. <bold>Conclusions:</bold> SA was associated with a lower in-hospital mortality in patients with acute heart disease. Comorbidities contributed to the protective effect of SA.