title: Comparison of cardiovascular co-morbidities and CPAP use in patients with positional and non-positional mild obstructive sleep apnea.
abstract: BACKGROUND
  This retrospective cohort study aimed to determine if there are differences in cardiovascular co-morbidities, blood pressure (BP) and continuous positive airway pressure (CPAP) use between patients with positional-dependent and nonpositional-dependent obstructive sleep apnea (OSA).
  
  
  METHODS
  Patients who were referred for overnight polysomnography for suspected OSA between 2007 and 2011 were screened. A total of 371 patients with OSA were included for analysis and divided into six groups according to positional-dependency and severity of OSA: positional mild (n = 52), positional moderate (n = 29), positional severe (n = 24), non-positional mild (n = 18), non-positional moderate (n = 70) and non-positional severe group (n = 178). The six groups were compared for anthropometric and polysomnographic variables, presence of cardiovascular co-morbidities, morning and evening BP and the changes between evening and morning BP, and CPAP device usage patterns.
  
  
  RESULTS
  Demographic and anthropometric variables showed non-positional severe OSA had poor sleep quality and higher morning blood pressures. Positional mild OSA had the lowest cardiovascular co-morbidities. Overall CPAP acceptance was 45.6%. Mild OSA patients had the lowest CPAP acceptance rate (10%), followed by moderate group (37.37%) and severe group (61.88%, P < 0.001). However, the significant difference in CPAP acceptance across OSA severity disappeared when the data was stratified by positional dependency.
  
  
  CONCLUSIONS
  This study found that positional mild OSA had less cardiovascular co-morbidities compared with subjects with positional severe OSA. Independent of posture, CPAP acceptance in patients with mild OSA was low, but CPAP compliance was similar in CPAP acceptors regardless of posture dependency of OSA. Since there are increasing evidences of greater cardiovascular risk for untreated mild OSA, improving CPAP acceptance among mild OSA patients may be clinically important regardless of posture dependency.
authors.forename: Yi-Chih
authors.initials: YC
authors.lastname: Huang
authors.forename: Chun-Yao
authors.initials: CY
authors.lastname: Lin
authors.forename: Chou-Chin
authors.initials: CC
authors.lastname: Lan
authors.forename: Yao-Kuang
authors.initials: YK
authors.lastname: Wu
authors.forename: Chor-Shen
authors.initials: CS
authors.lastname: Lim
authors.forename: Chun-Yao
authors.initials: CY
authors.lastname: Huang
authors.forename: Hsuan-Li
authors.initials: HL
authors.lastname: Huang
authors.forename: Kuan-Hung
authors.initials: KH
authors.lastname: Yeh
authors.forename: Yu-Chih
authors.initials: YC
authors.lastname: Liu
authors.affiliation: Division of Pulmonary Medicine, Department of Internal Medicine, Taipei Tzuchi Hospital, the Buddhist Tzuchi Medical Foundation, Xindian Dist, New Taipei City, Taiwan. mimi3461@ms45.hinet.net.
authors.forename: Mei-Chen
authors.initials: MC
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D015992:Body Mass Index; D015897:Comorbidity; D045422:Continuous Positive Airway Pressure; D006970:Disorders of Excessive Somnolence / Q000209:etiology*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D017286:Polysomnography; D011187:Posture; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012890:Sleep; D020181:Sleep Apnea, Obstructive / Q000453:epidemiology* / Q000503:physiopathology* / Q000628:therapy; D013997:Time Factors; D055105:Waist Circumference; D049629:Waist-Hip Ratio