Effect of CPAP Therapy on Cardiovascular Events and Mortality in Patients With Obstructive Sleep Apnea: A Meta-analysis
Guo J, Sun Y, Xue LJ, et al
Sleep Breath. 2016 Feb 12. [Epub ahead of print]
Serious cardiovascular outcomes, including mortality, are associated with obstructive sleep-disordered breathing. Given that obstructive sleep apnea (OSA) is quite common in both men and women aged 50 years or older, it remains important to determine whether treatment of OSA might improve cardiac outcomes of patients who also have cardiovascular disorders. Previous studies have not provided a clear answer, largely because they were underpowered.
The current study was a meta-analysis of 18 large, prospective, randomized, controlled studies with a total of 4146 patients. The included studies had "cardiovascular," "mortality," or "blood pressure" in their titles and comparing outcomes of patients given continuous positive airway pressure (CPAP) with those in patients who received sham therapy or with untreated control participants. The mean age was 63.4 years, and 75% of participants were male. Smokers and patients with type 2 diabetes were included.
The mean duration of CPAP administration was 5 hours per night, and the mean duration of follow-up was 30.5 months. The Epworth Sleepiness Scale was reduced in the CPAP group by -1.78 units (P < .001), suggesting that CPAP had been performed.
The risk for cardiovascular events of any type was slightly reduced in the CPAP group vs control (odds ratio, 0.84), but statistical significance was not reached (P = .53. Mortality, which was recorded in four studies involving 2020 participants), was again only slightly reduced in the CPAP arm (odds ratio, 0.85) and nonsignificant (P =.72). Stroke was similarly slightly lower but also nonsignificant. However, both systolic and diastolic blood pressures were significantly reduced, at -2.03 mm Hg and -1.79 mm Hg, respectively.
Cardiovascular diseases and OSA often go together, particularly because cigarette smoking and obesity are highly prevalent in both disorders. In addition, whenever body mass index and the presence of type 2 diabetes mellitus were recorded included in the meta-analysis, they were almost always present as well. One might say, parenthetically, that whenever a healthcare provider is confronted with one of these conditions, he or she should consider the presence of other comorbidities, regardless of whether they were presenting conditions.
Previous studies have addressed the question of whether using CPAP to treat patients with cardiac conditions and OSA would ameliorate the cardiovascular component and found results similar to the present ones—that is, CPAP had little benefit in terms of cardiovascular events and mortality, but provided some reduction in blood pressure. It is well known that weight loss improves OSA, but it now appears clear that the benefit of CPAP therapy does not extend to a significant reduction in cardiovascular outcomes.
There appears to be a connection between the disorders in question—namely that cardiovascular disorders, obesity, OSA, type 2 diabetes, and possibly metabolic syndrome and COPD are comorbidities.
Medscape Pulmonary Medicine © 2016 WebMD, LLC
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Can CPAP Therapy Improve Cardiovascular Events in Patients With Sleep Apnea? - Medscape - Mar 24, 2016.