Associations of Obstructive Sleep Apnea With Risk of Serious Cardiovascular Events. A Systematic Review and Meta-Analysis

Loke, Y., Brown, J., Kwok, C., Niruban, A., Myint, P.

Cir Cardiovascular Qual Outcomes. 2015;5:720-728.

PMID: 22828826

       The relationship between obstructive sleep apnea (OSA) and cardiovascular events remains unclear. This current study searched MEDLINE and EMBASE in January 2011 for prospective studies that followed up patients with OSA for incident heart disease, stroke, and cardiovascular mortality. They identified 9 relevant studies from 1731 citations. OSA was associated with incident stroke in a meta-analysis of 5 studies (8435 participants), odds ratio (OR) 2.24; 95% confidence interval (CI), 1.57-3.19. A significant association was seen in studies that were predominantly on men: OR, 2.87 (95% CI: 1.91-4.31), whereas data on women were sparse. In the overall analysis of 6 studies (8785 participants), OSA was no significantly associated with ischemic heart disease (OR: 1.56; 95% CI: 0.83-2.91). OSA was linked to cardiovascular death in 2 studies involving 2446 participants (OR: 2.09; 95% CI: 1.20-3.65). Regression analysis showed greater likelihood of stroke or cardiovascular events with increasing apnea-hypopnea index values.

       OSA appears to be associated with stroke, but the relationship with ischemic heart disease and cardiovascular mortality needs further research.

Future implications: The data was derived mainly from studies with predominance (55-79%) of men. There is much less evidence to accurately quantify the risk in women. Existing trials of continuous positive airway pressure (CPAP) have generally been of short duration, and focused on the assessment of surrogate markers rather than hard end points. More high-quality studies are need to evaluate these relationships and how the risk associated with OSA compares with other modifiable cardiovascular risk factors (ie: hypertension, diabetes mellitus, and smoking). Additional studies are need to determine whether better management of OSA leads to fewer cardiovascular events.

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