title: Continuous positive airway pressure therapy in non-sleepy patients with obstructive sleep apnea: results of a meta-analysis.
abstract: BACKGROUND
  Although continuous positive airway pressure (CPAP) has become the first line of therapy for obstructive sleep apnea (OSA), it remains controversial whether non-sleepy patients could benefit from CPAP treatment.
  
  
  METHODS
  We searched the online databases Medline, Embase, the Cochrane library and the Cochrane Central Registry of Controlled Trials to select eligible control trials, including non-sleepy OSA patients and those patients treated by CPAP or either sham CPAP or no CPAP.
  
  
  RESULTS
  Seven eligible studies (1,541 patients) were included. The pooled estimates of the mean changes after CPAP treatment for the systolic blood pressure (SBP) and diastolic blood pressure (DBP) were -0.51 mmHg (95% CI, -3.39 to 2.38 mmHg; P=0.73) and -0.92 mmHg (95% CI, -1.39 to -0.46 mmHg; P<0.001), respectively. CPAP should not improve subjective sleepiness in the minimally symptomatic OSA patients, as the change in the Epworth sleepiness scale (ESS) was -0.51 (95% CI, -1.68 to 0.67; P=0.397). However, CPAP can effectively reduce AHI or ODI by 15.57 events/h (95% CI, -29.32 to -1.82; P=0.026) compared to controls. However, the risk of cardiovascular events did not significantly decrease [odds ratio (OR), 0.80; 95% CI, 0.50 to 1.26; P=0.332] in the end.
  
  
  CONCLUSIONS
  CPAP treatment can reduce OSA severity in non-sleepy patients and minutely reduce the DBP, but CPAP seems to have no overall beneficial effects on subjective sleepiness, SBP, or cardiovascular risk.
authors.affiliation: Department of Respiratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Respiratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China.
authors.forename: Jinmei
authors.initials: J
authors.lastname: Luo
authors.affiliation: Department of Respiratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China.
authors.forename: Yixian
authors.initials: Y
authors.lastname: Qiao
authors.affiliation: Department of Respiratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xiao
keywords: Sleep apnea; cardiovascular diseases; continuous positive airway pressure/method (CPAP/method); hypertension; obstructive/complications/therapy