Prognostic Implications of OSA in Acute Coronary Syndrome by Obesity Status

Background: A close relationship exists between OSA and obesity. The impact of obesity on the prognostic significance of OSA in patients with acute coronary syndrome (ACS) remains unclear.

Research question: Do the effects of OSA on subsequent cardiovascular events in patients with ACS vary with obesity status?

Study design and methods: This is a prospective cohort study. Patients 18 to 85 years of age who were hospitalized for ACS were consecutively enrolled and underwent portable sleep monitoring after clinical stabilization. OSA was defined as an apnea hypopnea index ≥ 15 events/h. The primary end point was major adverse cardiovascular and cerebrovascular event (MACCE), including cardiovascular death, hospitalization for ACS, stroke, ischemia-driven revascularization, or hospitalization for heart failure.

Results: Among 1,920 patients enrolled (84.5% male; mean age ± SD, 56.4 ± 10.5 years), 1,013 (52.8%) had OSA, and 718 (37.4%) were obese (BMI ≥ 28 kg/m²). During 2.9 years (1.5, 3.6 years) follow-up, the incidence of MACCE was significantly higher in patients with obesity than in patients without obesity (hazard ratio [HR], 1.29; 95% CI, 1.06-1.58; P = .013). Although the prevalence of OSA was lower in patients without obesity than in those with obesity (43.9% vs 67.5%; P < .001), OSA independently predicted the incidence of MACCE only in patients without obesity (adjusted HR, 1.34; 95% CI, 1.03-1.75; P = .03), but not in patients with obesity (adjusted HR, 1.10; 95% CI, 0.78-1.55; P = .58). No significant interaction between obesity and OSA was noted (P for interaction = .35). The incremental risk associated with OSA in patients without obesity might be explained by more hospitalization for ACS and ischemia-driven revascularization.

Interpretation: For patients with ACS, OSA was independently associated with an increased risk of subsequent events, particularly among patients without obesity. These findings highlight the importance of identifying OSA in nonobese patients with ACS.

Clinical trial registration: ClinicalTrials.gov; No.: NCT03362385; URL: www.

Clinicaltrials: gov.