Effect Heterogeneity of CPAP on MACE by Nocturnal Hypoxia Burden in Older Adults OSAS: A Propensity Score Matching...

Obstructive sleep apnea syndrome (OSAS) is a common disease closely linked to cardiovascular events, with its prevalence markedly rising among aging populations. The core pathological feature of hypoxia clearly has an impact on cardiovascular health. As standard therapy, continuous positive airway pressure (CPAP) holds undetermined long-term cardiovascular benefits in older OSAS patients, especially across different hypoxia phenotypes.

This multicenter cohort study enrolled 350 older OSAS patients, who were 1:4 matched into the CPAP group (n=70) and non-CPAP group (n=280) via propensity score matching to balance baseline confounders including age, BMI, apnea hypopnea index and comorbidities. With 4-5 years of follow-up and MACE as the primary endpoint, Cox regression and subgroup analyses stratified by OSAS severity and nocturnal hypoxia burden were performed.

Baseline indicators were well-balanced between two groups. Regular CPAP use independently reduced MACE risk in older OSAS patients (adjusted hazard ratio (HR)=0.377, 95% confidence interval (CI): 0.150-0.947, P=0.038). Advanced age and carotid atherosclerosis acted as independent risk factors for MACE (adjusted HR for age = 1.063, adjusted HR for CA = 3.011, both P < 0.001). Notably, subgroup analysis revealed that hypoxia phenotype dictates CPAP's protective efficacy: prominent MACE reduction was observed in patients with high nocturnal hypoxia burden (T90 ≥ 1.5% or 5.0%), individuals under 70 years and overweight populations (aHR_T90≥1.5% = 0.198, aHR_T90≥5.0% = 0.120, aHR_age<70 = 0.110, aHR_overweight = 0.306, all P < 0.05), whereas CPAP yielded no significant cardiovascular benefits in patients with mild hypoxia burden (T90 < 1.5%).

Our findings provide novel clinical evidence that adherent CPAP intervention is significantly associated with reduced long-term cardiovascular risks among older patients with OSAS. Clinically, individualized management tailored to hypoxia phenotypic features, instead of universal CPAP administration, may help maximize potential cardiovascular benefits and optimize comprehensive treatment strategies for this older population.