title: Progression of obstructive sleep apnoea syndrome in Japanese patients.
abstract: OBJECTIVE
  The aggravation of obstructive sleep apnoea syndrome (OSAS) is reportedly associated with weight gain. The present study investigated the factors associated with worsening of respiratory functional parameters in Japanese OSAS patients who showed no body weight change during the follow-up period.
  
  
  METHODS
  A follow-up polysomnography (PSG) was performed in 82 patients with a mean of 7.5 years after the diagnostic PSG, and the apnoea-hypopnoea index (AHI), respiratory event duration, minimum percutaneous oxygen saturation (SpO2), baseline SpO2, and 3 % oxygen desaturation index (ODI) during sleep were compared between the two PSGs. Furthermore, factors associated with worsened AHI, respiratory event duration, and minimum SpO2 were investigated using logistic regression analysis.
  
  
  RESULTS
  No significant differences were observed in AHI, baseline SpO2, and 3 % ODI between the two PSGs. However, there was a significantly increased respiratory event duration and decreased minimum SpO2 observed. In addition, 17 patients had a ≥25 % AHI increase, and the age of 40-60 years and initial OSAS severity (mild and moderate) were the significantly associated factors. Age of ≥60 years and a baseline body mass index (BMI) of ≥25 kg/m(2) were significantly associated with prolonged respiratory event duration. The age of 40-60 years was significantly associated with decreased minimum SpO2.
  
  
  CONCLUSIONS
  Untreated middle-aged patients may be at a high risk for worsened AHI and SpO2 even without weight gain.
authors.affiliation: Japan Somnology Center, Neuropsychiatric Research Institute, Tokyo, Japan.|Sleep and Stress Clinic, Tokyo, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Hayashida
authors.affiliation: Japan Somnology Center, Neuropsychiatric Research Institute, Tokyo, Japan.|Department of Somnology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Mina
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: Japan Somnology Center, Neuropsychiatric Research Institute, Tokyo, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Namba
authors.affiliation: Sleep and Stress Clinic, Tokyo, Japan.|Department of Somnology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Ueki
authors.affiliation: Department of Respiratory Medicine, Tokyo Medical University, Tokyo, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Nakayama
authors.affiliation: Japan Somnology Center, Neuropsychiatric Research Institute, Tokyo, Japan.|Department of Somnology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Eiki
authors.initials: E
authors.lastname: Ito
authors.affiliation: Higami Ear-Nose-Throat, Snore and Sleep Clinic, Tottori, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Higami
authors.affiliation: Japan Somnology Center, Neuropsychiatric Research Institute, Tokyo, Japan. inoue@somnology.com.|Department of Somnology, Tokyo Medical University, Tokyo, Japan. inoue@somnology.com.|Department of Psychiatry, Tokyo Medical University, 6-7-1, Nishishinjuku, Shinjuku-ku, Tokyo, 160-0023, Japan. inoue@somnology.com.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Inoue
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001835:Body Weight; D045422:Continuous Positive Airway Pressure; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis*
keywords: Middle age; Natural evolution; Obstructive sleep apnoea syndrome; Progression