title: Investigation of trends and characteristics in patients with obstructive sleep apnea.
abstract: BACKGROUND
  Oral appliance (OA) therapy for obstructive sleep apnea (OSA) has only been part of Japan's National Health care coverage plan since 2004. Subsequently, not enough time has passed to establish the medical trends and characteristics of OSA patients in Japanese Dental Hospitals.
  
  
  OBJECTIVE
  The aim of this study was to investigate the medical trends and the characteristics in patients with OSA who visited our clinic, and to compare our findings with previous studies.
  
  
  METHODS
  Epidemiological survey (retrospective study).
  
  
  METHODS
  Two hundred and one patients were recruited at the Internal Medicine Division in the Tsurumi University Dental Hospital from February 2006 to December 2008, consecutively. Patients received a medical interview, and a detailed sleep analysis that included a polysomnography (PSG) to verify the exact nature of their condition. The efficacy of OA was assessed in 49 patients who wore an OA and underwent PSG.
  
  
  RESULTS
  Of all subjects, 141 patients visited the Prosthodontic Division to receive OA therapy, 38 patients were treated or received a follow up examination in the Internal Medicine Division. The dropout rate was 10.4% in the all subjects, 17.0% in patients who visited the Prosthodontic Division. The male-to-female ratio was 3.3:1, 3.0:1 in patients who visited the Prosthodontic Division. In addition, females had a lower rate of OAS severity than males. In our patients, the major complication was hypertension and cardiac disease. The success rate of OA was 75.5%.
  
  
  CONCLUSIONS
  This approach allowed us to reveal some of the trends and characteristics in our patients.
authors.affiliation: Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine, Yokohama, Japan.
authors.forename: Chieko
authors.initials: C
authors.lastname: Ishikawa
authors.forename: Yuko
authors.initials: Y
authors.lastname: Shigeta
authors.forename: Takumi
authors.initials: T
authors.lastname: Ogawa
authors.forename: Shinya
authors.initials: S
authors.lastname: Hirai
authors.forename: Eriko
authors.initials: E
authors.lastname: Ando
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ikawa
authors.forename: Shintaro
authors.initials: S
authors.lastname: Kasama
authors.forename: Keisuke
authors.initials: K
authors.lastname: Ihara
authors.forename: Noboru
authors.initials: N
authors.lastname: Kawamura
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Mizuno
authors.forename: Shunji
authors.initials: S
authors.lastname: Fukushima
authors.forename: Toshio
authors.initials: T
authors.lastname: Hosoi
authors.forename: Jun
authors.initials: J
authors.lastname: Nejima
authors.forename: C
authors.initials: C
authors.lastname: Ohkubo