Self-reported Snoring Patterns Predict Stroke Events in High-Risk Patients With OSA: Post Hoc Analyses of the SAVE Study

Background: The relation of snoring to risks of stroke and other major cardiovascular (CV) events is uncertain.

Research question: We aimed to determine associations of snoring patterns and major CV events in relation to OSA among participants of the international Sleep Apnea cardiovascular Endpoints (SAVE) trial.

Study design and methods: Post hoc analyses of the SAVE trial, which involved 2,687 patients with coexisting moderate-to-severe OSA and established coronary or cerebral CV disease, who were randomly allocated to CPAP treatment plus usual care or usual care alone, and followed-up for a median 3.5 years. Associations of self-reported snoring patterns (frequency and loudness) and breathing pauses collected on the Berlin questionnaire at baseline and multiple times during follow-up, and adjudicated composites of CV outcomes (primary, CV death, nonfatal myocardial infarction, nonfatal stroke, and hospitalization for unstable angina, heart failure, or transient ischemic attack; and separately of cardiac and cerebral events), were evaluated in time-dependent Cox proportional hazards models adjusted for various confounders including the apnea-hypopnea index.

Results: Increase (per category) of snoring frequency (adjusted hazard ratio [HR], 1.10; 95% CI, 1.02-1.20; P = .015), loudness (HR, 1.16; 95% CI, 1.06-1.27; P = .001), and breathing pauses (HR, 1.16; 95% CI, 1.08-1.25; P < .001) at any time point during follow-up were each associated with the primary composite CV outcome. These associations were driven by significant associations for cerebral rather than cardiac events, and positive interactions between the three snoring patterns for cerebral events. There was no significant interaction between CPAP treatment and snoring variables for cerebral events.

Interpretation: Snoring in patients with OSA with established CV disease is associated with greater risks of cerebral but not cardiac events, independent of CPAP treatment and frequency of apnea and hypopnea events.

Trial registry: ClinicalTrials.gov; No.: NCT00738179; URL: www.clinicaltrials.gov.