title: A randomized cross-over study of auto-continuous positive airway pressure versus fixed-continuous positive airway pressure in patients with obstructive sleep apnoea.
abstract: OBJECTIVE
  To compare the efficacy of auto-CPAP (AutoSet Spirit, ResMed) versus fixed-CPAP (S6 Elite, ResMed) in improving daytime sleepiness, health status, objective compliance and the ultimate treatment preference in patients with severe OSA.
  
  
  METHODS
  The study recruited 43 subjects aged 18-65 years with newly diagnosed severe OSA (AHI >30/h). Patients were initially treated with either auto-CPAP or fixed-CPAP for 2 months and then crossed over after a washout period of 1 week for another 2 months.
  
  
  RESULTS
  The study was completed by 41 patients. Results are presented as mean (SE). Use of auto-CPAP in the first and the second month was significantly higher than that of fixed-CPAP [129.7 (9.9) and 130.5 (10.7) h vs 115.2 (9.5) and 113.2 (9.4) h, P = 0.04 and 0.01], whereas mean hourly use per night was 4.3 and 4.4 h versus 3.8 and 3.7 h, respectively. The Epworth sleepiness scores improved after 1 month in both treatments (13.4 to 8.5 and 8.2, P < 0.01 for both). The Sleep apnoea quality of life index improved in the first month in both compared with baseline [4.6 (0.2) to 5.0 (0.2) for auto-CPAP and 4.9 (0.2) for fixed-CPAP, P = 0.01 and 0.04, respectively], with no difference between the two treatments. Nine and 30 patients preferred auto-CPAP and fixed-CPAP, respectively, at the end of the trial, whereas 14 and 25 patients would have chosen the same treatments if cost had not been a consideration.
  
  
  CONCLUSIONS
  Auto-CPAP and fixed-CPAP were equally effective in improving symptoms and health status in patients with severe OSA. Usage was higher with auto-CPAP, but more patients ultimately chose fixed-CPAP.
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong, China.
authors.forename: Kin W
authors.initials: KW
authors.lastname: To
authors.forename: Wing C
authors.initials: WC
authors.lastname: Chan
authors.forename: Kah L
authors.initials: KL
authors.lastname: Choo
authors.forename: Wai K
authors.initials: WK
authors.lastname: Lam
authors.forename: Kwan K
authors.initials: KK
authors.lastname: Wong
authors.forename: David S
authors.initials: DS
authors.lastname: Hui
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D045422:Continuous Positive Airway Pressure / Q000379:methods*; D018592:Cross-Over Studies; D006304:Health Status; D006723:Hong Kong; D006801:Humans; D008875:Middle Aged; D010349:Patient Compliance; D017060:Patient Satisfaction; D011788:Quality of Life; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000628:therapy*; D016896:Treatment Outcome