title: Effect of automatic versus fixed continuous positive airway pressure for the treatment of obstructive sleep apnea: an up-to-date meta-analysis.
abstract: OBJECTIVE
  This study was made to evaluate the effect of automatic continuous positive airway pressure (auto-CPAP) versus fixed continuous positive airway pressure (fixed CPAP) in reducing the apnea-hypopnea index (AHI) and the mean therapy pressure, improving subjective sleepiness, sleep architecture, patient compliance, and preference in patients with obstructive sleep apnea.
  
  
  METHODS
  We searched the electronic databases MEDLINE, EMBASE, the Cochrane Library, and Google Scholar. Randomized controlled trials comparing auto-CPAP with fixed CPAP were reviewed. Continuous variables were presented as mean difference (MD), and dichotomous data as odds ratio (OR), both with 95% confidence intervals (CI).
  
  
  RESULTS
  We identified 19 studies consisting of 845 patients. Compared to fixed CPAP, the use of auto-CPAP reduced mean therapy pressure (MD -1.64; 95% CI -2.46 to -0.82), improved patient compliance (MD 0.23; 95% CI 0.06 to 0.39), increased the percentage of total sleep time (TST) in slow wave sleep (MD 5.11; 95% CI 1.34 to 8.88), and decreased the percentage of TST in stage 2 sleep (MD -4.75; 95% CI -9.38 to -0.11). Moreover, more patients preferred auto-CPAP therapy (OR 3.65; 95% CI 1.27 to 10.53). There were nonsignificant trends towards better outcomes with auto-CPAP for AHI and Epworth Sleepiness Scale (MD -0.43; 95% CI -1.10 to 0.23, and MD -0.24; 95% CI -0.74 to 0.25, respectively), though these are of questionable clinical significance.
  
  
  CONCLUSIONS
  There are some aspects of clinical care, such as a mild improvement in compliance, patient preference, and sleep architecture that appear to favor the use of auto-CPAP compared to fixed CPAP. The clinical relevance of these findings requires further study.
authors.affiliation: Department of Sleep Disorder Center, Nanfang Hospital, Southern Medical University, No. 1838 Guangzhou Dadao Bei, Guangzhou, 510515, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Xu
authors.forename: Taoping
authors.initials: T
authors.lastname: Li
authors.forename: Dongning
authors.initials: D
authors.lastname: Wei
authors.forename: Yuan
authors.initials: Y
authors.lastname: Feng
authors.forename: Lewu
authors.initials: L
authors.lastname: Xian
authors.forename: Haiqing
authors.initials: H
authors.lastname: Wu
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
mesh_terms: D045422:Continuous Positive Airway Pressure / Q000379:methods*; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis / Q000628:therapy; D006801:Humans; D010349:Patient Compliance; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000628:therapy*; D011795:Surveys and Questionnaires; D013813:Therapy, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome