title: Study on the frequency and risk factors of moderate-to-severe sleep apnea syndrome in rheumatoid arthritis.
abstract: OBJECTIVE
  We aimed to investigate the frequency of moderate-to-severe sleep apnea syndrome (SAS) that possibly influences long-term prognosis in patients with rheumatoid arthritis (RA), and to analyze the risk factors for this group.
  
  
  METHODS
  We examined respiratory disturbance index (RDI) by polysomnography in 62 hospitalized RA patients. Risk factors of moderate-to-severe SAS (RDI ≥20) were analyzed using a multivariate logistic regression analysis.
  
  
  RESULTS
  RA was complicated by moderate-to-severe SAS in 13/62 (20.9%) cases. The highest stage of temporomandibular joint abnormality (TMJA) and a high value of health assessment questionnaire-disability index (HAQ-DI) were significant risk factors, according to the results of the multivariate logistic regression analysis (p < 0.0001 and p = 0.010, respectively). Contrary to these results, RDI was not related to the disease activity indexes of RA and other clinical characteristics.
  
  
  CONCLUSIONS
  We clarified that the highest TMJA stage and a high value of HAQ-DI are novel important risk factors for moderate-to-severe SAS in RA patients.
authors.affiliation: a Department of Internal Medicine , Center for Rheumatic Diseases, Dohgo Spa Hospital , Matsuyama City , Ehime , Japan and.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Mutoh
authors.affiliation: a Department of Internal Medicine , Center for Rheumatic Diseases, Dohgo Spa Hospital , Matsuyama City , Ehime , Japan and.
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Okuda
authors.affiliation: b Department of Clinical Immunology and Rheumatology , Hiroshima University Hospital , Hiroshima City, Hiroshima , Japan.
authors.forename: Sho
authors.initials: S
authors.lastname: Mokuda
authors.affiliation: a Department of Internal Medicine , Center for Rheumatic Diseases, Dohgo Spa Hospital , Matsuyama City , Ehime , Japan and.
authors.forename: Naoya
authors.initials: N
authors.lastname: Sawada
authors.affiliation: a Department of Internal Medicine , Center for Rheumatic Diseases, Dohgo Spa Hospital , Matsuyama City , Ehime , Japan and.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Matoba
authors.affiliation: a Department of Internal Medicine , Center for Rheumatic Diseases, Dohgo Spa Hospital , Matsuyama City , Ehime , Japan and.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yamada
authors.affiliation: a Department of Internal Medicine , Center for Rheumatic Diseases, Dohgo Spa Hospital , Matsuyama City , Ehime , Japan and.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Jouyama
authors.affiliation: a Department of Internal Medicine , Center for Rheumatic Diseases, Dohgo Spa Hospital , Matsuyama City , Ehime , Japan and.
authors.forename: Makoto
authors.initials: M
authors.lastname: Onishi
authors.affiliation: a Department of Internal Medicine , Center for Rheumatic Diseases, Dohgo Spa Hospital , Matsuyama City , Ehime , Japan and.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Takasugi
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D011379:Prognosis; D012307:Risk Factors; D012720:Severity of Illness Index; D012891:Sleep Apnea Syndromes / Q000150:complications* / Q000175:diagnosis
keywords: Frequency; HAQ-DI; RA; Sleep apnea syndrome; Temporomandibular joint