Continuous positive airway pressure (CPAP) was effective for preventing cardiovascular disease in patients with severe obstructive sleep apnea (OSA), although patients with very severe OSA still had a high rate of events, according to a study published in the Journal of Cardiology.

A total of 91 patients (mean age, 57.3 ± 13.4 years; 75% men; mean body mass index, 26.0±4.24 kg/m2) with OSA were included in the analysis. In this cohort, the mean apnea hypopnea index (AHI) was 35.6 ± 21.9 events/hour, and 66% of patients had hypertension, 13.2% had diabetes mellitus, and 24.2% had dyslipidemia. Participants had initiated medication for their specific condition prior to study start.

All patients who had an indication for CPAP were treated and categorized into 3 groups: mild/moderate OSA (group S), with AHI <30 events/hour (n=44); severe OSA (group SS) with AHI 30 to 55 events/hour (n=29); and very severe OSA (group VSS) with AHI >55 events/hour (n=18). The study’s primary endpoint was the composite outcome of fatal and nonfatal coronary artery disease, hospitalization for heart failure, stroke, and any cause of death.

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The primary event rate in the 5-year follow-up for the SS group (3 events, 7%) was the same as that in the S group (3 events, 10%). However, the VSS group had a significantly higher primary event rate compared with the other 2 groups (6 events, 33%; P < .05). The VSS group had the highest hazard ratio compared with other risk factors in a Cox regression analysis.

Study limitations include the small sample size and event rate and the lack of a control group. In addition, many participants had other CVD risk factors.

“In most previous studies, patients with very severe OSA were included in the severe OSA group; thus, the group differences might affect the previous results of studies evaluating CPAP efficacy,” noted the researchers. “Systemic medical treatment for the OSA-related risk burden, in addition to strict CPAP treatment, might be needed to prevent cardiovascular events in patients with very severe OSA.”


Hamaoka T, Murai H, Takata S, et al. Different prognosis between severe and very severe obstructive sleep apnea patients; five year outcomes [published online June 30, 2020]. J Cardiol. doi:10.1016/j.jjcc.2020.06.010

This article originally appeared on The Cardiology Advisor