[Impact of the mismatch between respiratory event frequency and hypoxic burden on cardiovascular outcomes in patients with obstructive sleep apnea].

Abstract

Objective: To investigate the impact of the mismatch between respiratory event frequency and hypoxic burden on cardiovascular outcomes in patients with obstructive sleep apnea (OSA). Methods: This study enrolled 3 754 adult OSA patients from the Sleep Heart Health Study, a prospective cohort study. Respiratory event frequency and hypoxic burden were assessed using the apnea-hypopnea index (AHI) and the percentage of time spent with oxygen saturation below 90% (T90), respectively. Patients were stratified into three groups based on the tertile alignment of AHI and T90: the matched group (AHI and T90 in the same tertile), the AHI-dominant group (AHI in a higher tertile than T90), and the T90-dominant group (T90 in a higher tertile than AHI). The primary outcome was major adverse cardiovascular events (MACE), defined as a composite of cardiovascular death, myocardial infarction, heart failure, and revascularization. Cox regression analysis was used to explore the association between AHI-T90 matching status and MACE. Kaplan-Meier survival analysis was performed to compare the prognosis among the groups. Restricted cubic spline (RCS) analysis was used to evaluate the association between the relative difference of AHI and T90 and MACE. Results: The age of the participants was 65 (57, 74) years, and 1 997 (53.2%) were men. Among them, 1 745 (46.5%) patients exhibited an AHI-T90 mismatch. There were 2 009 patients in the matched group, 882 in the AHI-dominant group, and 863 in the T90-dominant group. During a mean follow-up of 10.3 years, 974 patients (25.9%) experienced MACE. Kaplan-Meier curves showed that the incidence of MACE was significantly higher in the mismatch groups compared to the matched group (both P_log-rank<0.05). Multivariable Cox regression analysis demonstrated that the AHI-dominant group (HR=1.173, 95%CI 1.004-1.369, P=0.044) and the T90-dominant group (HR=1.187, 95%CI 1.016-1.386, P=0.031) were independently associated with MACE. RCS revealed that the risk of MACE was lowest when the relative difference between AHI and T90 was minimal. Conclusion: Mismatch between respiratory event frequency and hypoxic burden represents a distinct OSA phenotype associated with a higher incidence of MACE.