Tools for Practice


#218 CPAP—Breath of life, or just hot air?


CLINICAL QUESTION
Does continuous positive airway pressure (CPAP) reduce cardiovascular disease (CVD) or mortality in patients with obstructive sleep apnea?

BOTTOM LINE
There is a lack of convincing evidence that CPAP reduces CVD or mortality in patients with moderate-to-severe obstructive sleep apnea. Adherence to CPAP treatment in most clinical trials is low (1.4-5.8 hours/night at one year). Modest clinically important improvements in daytime sleepiness have been demonstrated. Quality of life scales have also demonstrated improvement, although clinical significance is unclear. 


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EVIDENCE
  • Three meta-analyses of randomized controlled trials (RCTs).1,2,3 Patients were predominantly male, mean age >60 years, with moderate-to-severe obstructive sleep apnea. 
    • No statistical different in CPAP versus standard care or sham:  
      • CVD:1-3 7% CPAP versus 8% control (seven trials, 4,562 patients).1 
      • Cardiovascular death:1,2 9% CPAP versus 8% control (seven trials, 5,476 patients).1 
      • Acute coronary syndrome:1,2 3% CPAP versus 3% control (seven trials, 4,562 patients).1 
      • Stroke:1-3 4% CPAP versus 4% control (six trials, 4,171 patients).1 
    • Post-hoc analysis did not identify any significant relationship between CPAP and CVD regardless of apnea severity, length of follow-up, or adherence.1 
    • Limitations: Included studies somewhat heterogeneous with inclusion of central apnea patients in some outcomes, differences in length of follow-up (2-68 months), and adherence to CPAP (1.4-5.8 hours/night at one year).  
Context:  
  • Obstructive sleep apnea is associated with increased risk of CVD and mortality.4,5 
  • CPAP modestly improves daytime sleepiness by 1.6-3.8 on a 24-point scale, which is likely clinically detectable.6-10 
  • CPAP is associated with modest improvements in quality of life measures (example ~3.3-9.7 improvement on a 100-point scale)11 with uncertain clinical relevance.  
  • CPAP significantly decreases blood pressure (mean reduction 2.5 mmHg systolic and 2 mmHg diastolic).12 
  • Observational data suggests that CPAP use significantly reduces motor vehicle accidents.13 A large RCT (2,717 patients) reports a non-statistically significant trend towards injury reduction (7.4% versus 8.8%, p = 0.06).14 
August 20, 2018

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Author(s):

  • Christina Korownyk MD CCFP
  • Peter (Ran) Yang BScPharm ACPR

1. Yu J, Zhou Z, McEvoy RD, et al. JAMA. 2017; 318:156-66.

2. Abuzaid AS, Al Ashry HS, Elbadawi A, et al. Am J Cardiol. 2017; 120:693-9.

3. Guo J, Sun Y, Xue LJ, et al. Sleep Breath. 2016; 20:965-74.

4. Laratta CR, Ayas NT, Povitz M, et al. CMAJ. 2017; 189(48):E1481-88.

5. Kendzerska T, Mollayeva T, Gershon AS, et al. Sleep Med Rev. 2014; 18(1):49-59.

6. Giles TL, Lasserson TJ, Smith BH, et al. Cochrane Database Syst Rev. 2006; (3):CD001106.

7. Campos-Rodriguez F, Queipo-Corona C, Carmona-Bernal C, et al. Am J Respir Crit Care Med. 2016; 194(10):1286-94.

8. Phillips CL, Grunstein RR, Darendeliler MA, et al. Am J Respir Crit Care Med. 2013; 187:879-87.

9. Patel S, Kon S, Nolan C, et al. Am J Respir Crit Care Med. 2018; 197(7):961-3.

10. Dauvilliers Y, Bassetti C, Lammers GJ, et al. Lancet Neurol. 2013; 12(11):1068-75.

11. Kuhn E, Schwarz EI, Bratton DJ, et al. Chest. 2017; 151:786-94.

12. Bratton DJ, Gaisl T, Wons AM, et al. JAMA. 2015; 314(21):2280-93.

13. Tregear S, Reston J, Schoelles K, et al. Sleep 2010; 33:1373-80.

14. McEvoy RD, Antic NA, Heeley E, et al. N Engl J Med. 2016; 375(10):919-31.

Authors do not have any conflicts of interest to declare.