Rationale: It is unknown whether obstructive sleep apnea (OSA) may be a risk factor for incident cardiovascular events in women.
Objectives: We sought to investigate whether OSA increases the incidence of a composite of stroke or coronary heart disease (CHD) in women, and the role of continuous positive airway pressure (CPAP) treatment on this association.
Methods: This was a prospective, observational study conducted in two Spanish teaching hospitals between 1998 and 2007. Consecutive women referred for suspected OSA and free of previous stroke and CHD were analyzed. Women with an apnea-hypopnea index (AHI) less than 10 comprised the control group, and those with an AHI greater than or equal to 10 were diagnosed with OSA and classified as CPAP-treated (adherence ≥ 4 h/d) or untreated (adherence < 4 h/d or not prescribed). The follow-up ended in December 2010.
Measurements and main results: A total of 967 women were studied (median follow-up, 6.8 yr; interquartile range, 5.2-8.2). The untreated OSA group showed a greater incidence rate of the composite outcome than the control group (2.19 vs. 0.54 per 100 person-years; P < 0.0005). Compared with the control group, the fully adjusted hazard ratios for the composite outcome incidence were 2.76 (95% confidence interval [CI], 1.35-5.62) for the untreated OSA group, and 0.91 (95% CI, 0.43-1.95) for the CPAP-treated group. When the type of cardiovascular event was separately assessed, untreated OSA showed a stronger association with incident stroke (adjusted hazard ratio, 6.44; 95% CI, 1.46-28.3) than with CHD (adjusted hazard ratio, 1.77; 95% CI, 0.76-4.09).
Conclusions: In women, untreated OSA is associated with increased incidence of serious cardiovascular outcomes, particularly incident stroke. Adequate CPAP treatment seems to reduce this risk.
Keywords: continuous positive airway pressure; coronary heart disease; female sex; obstructive sleep apnea; stroke.