(HealthDay News) – Untreated obstructive sleep apnea (OSA) is associated with increased cardiovascular mortality in women, but continuous positive airway pressure (CPAP) treatment reduces the risk of mortality, according to a study published in the January 17 issue of the Annals of Internal Medicine.

Francisco Campos-Rodriguez, M.D., from Valme University Hospital in Seville, Spain, and colleagues observed 1,116 women, consecutively referred to two sleep clinics for suspected OSA, from 1998 to 2007. The controls had an apnea-hypopnea index (AHI) of <10. OSA was defined as an AHI of ≥10 (classified as mild to moderate [AHI of 10 to 29] or severe [AHI of ≥30]). Patients were classified according to CPAP treatment, as treated (adherence four hours or more per day) or untreated (adherence less than four hours per day or not prescribed). Participants were followed up until December 2009 for a primary end point of cardiovascular death.

The researchers found that the control group had a significantly lower cardiovascular mortality rate (0.28 per 100 person-years) than the untreated groups with mild to moderate OSA or severe OSA (0.94 per 100 person-years and 3.71 per 100 person-years, respectively). Compared with the control group, the fully adjusted hazard ratios for cardiovascular mortality were 3.50 and 0.55 for the untreated and treated, severe OSA groups, respectively, and 1.60 and 0.19 for the untreated and treated, mild to moderate OSA groups, respectively.

“Severe OSA is associated with cardiovascular death in women, and adequate CPAP treatment may reduce this risk,” the authors write.

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