title: Clinical, polysomnographic, and CPAP titration features of obstructive sleep apnea: Mixed versus purely obstructive type.
abstract: OBJECTIVE
  To determine whether obstructive sleep apnea syndrome (OSAS) patients with mixed sleep apnea (MSA) have different clinical, polysomnographic, and continuous positive airway pressure (CPAP) titration findings compared to OSAS patients without MSA.
  
  
  METHODS
  We retrospectively reviewed the records of OSAS patients who had undergone CPAP titration and categorized them into pure-OSA and mixed-OSA groups. Demographic features, daytime sleepiness, and apnea severity were compared between the two groups using univariate and multivariate analyses. CPAP titration findings were also compared between the two groups.
  
  
  RESULTS
  One hundred and ninety-five subjects (n=126 pure-OSA; n=69 mixed-OSA) were included in the analysis. Compared to the pure-OSA group, the mixed-OSA group had a higher percentage of males (p=0.003) and a higher body mass index (p=0.044), Epworth Sleepiness Scale score (p=0.028), and apnea-hypopnea index (AHI) (p<0.001). In logistic regression analysis, older age, male sex, and higher body mass index were independently associated with mixed-OSA before PSG study. When using AHI as a covariable, the higher AHI with older age, male sex, and daytime sleepiness was independently related to mixed-OSA. The mixed-OSA group had a higher percentage of patients with complex sleep apnea, a lower percentage of patients with optimal titration, and a higher titrated pressure than the pure-OSA group.
  
  
  CONCLUSIONS
  Severe OSA, older age, male sex, obesity, and daytime sleepiness were related to mixed-OSA. Complex sleep apnea, less optimal titration, and a higher titrated CPAP were also associated with MSA in OSAS patients.
authors.affiliation: Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea. Electronic address: salee@amc.seoul.kr.
authors.forename: Sang-Ahm
authors.initials: SA
authors.lastname: Lee
authors.affiliation: Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Gha-Hyun
authors.initials: GH
authors.lastname: Lee
authors.affiliation: Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Yoo-Sam
authors.initials: YS
authors.lastname: Chung
authors.affiliation: Department of Pulmonary Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Woo Sung
authors.initials: WS
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D045422:Continuous Positive Airway Pressure; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012189:Retrospective Studies; D012891:Sleep Apnea Syndromes / Q000175:diagnosis*; D020181:Sleep Apnea, Obstructive / Q000145:classification* / Q000175:diagnosis*
keywords: Apnea–hypopnea index; CPAP titration; Central sleep apnea; Complex sleep apnea; Continuous positive airway pressure; Mixed sleep apnea; Obstructive sleep apnea