Recent randomized controlled trials did not show cardiovascular benefits of continuous positive airway pressure (CPAP) in adults with coronary artery disease (CAD) and obstructive sleep apnea (OSA) in intention-to-treat analysis. It has been argued that exclusion of OSA patients with excessive daytime sleepiness (EDS), who may be most likely to benefit from CPAP treatment, may be a reason for the null results.
We addressed 1) the effect of concomitant EDS on adverse outcomes in patients with CAD and OSA, and, 2), whether the cardiovascular benefit of CPAP adherence differs between individuals with vs. without EDS.
This was a secondary analysis of the RICCADSA trial, conducted in Sweden between 2005 and 2013. Data were analyzed from 155 CAD patients with OSA (apnea-hypopnea index ≥ 15/h) and EDS (Epworth Sleepiness Scale [ESS] score≥10), who were allocated to CPAP, and 244 patients without EDS (ESS<10), who were randomized to CPAP or no-CPAP. Patients who were allocated to no-CPAP or non-adherent (CPAP usage< 4 hours/night) were compared to adherent patients (CPAP usage ≥ 4 hours/night) at 1-year follow-up. Inverse-probability of treatment weighting was applied to mimic randomization of EDS. The primary end-point was the first event of repeat revascularization, myocardial infarction, stroke or cardiovascular mortality.
The median follow-up was 52.2 months. The incidence of the primary endpoint did not differ significantly between the EDS vs. no-EDS groups in the entire cohort. Within the adherent group, patients without EDS had a significant decreased risk compared to patients with EDS (adjusted hazard ratio 0.41, 95% confidence interval 0.20-0.85; p = 0.02).
Adverse cardiovascular outcomes did not differ by levels of EDS for CAD patients with OSA, who were untreated or non-adherent to treatment. CPAP use, at least 4 hours/night, was associated with reduced adverse outcomes in participants without EDS. Clinical trial registered at Clinicaltrials.gov (NCT00519597).