title: Morbidity and mortality risk ratios are elevated in severe supine dominant OSA: a long-term follow-up study.
abstract: OBJECTIVE
  Obstructive sleep apnoea (OSA) is a common public health problem. Sleeping position dependency has been related to OSA, and around half of OSA patients suffer from positional OSA where majority of the respiratory events occur in supine position. The consequences of supine dominant OSA have not been thoroughly investigated in long-term follow-up studies. The aim of the study was to retrospectively investigate the effects of supine dominant OSA on morbidity and mortality risk ratios during long-term follow-up and compare the findings with a non-supine OSA group at different OSA severities.
  
  
  METHODS
  Ambulatory polygraphic recordings of 793 patients with median follow-up time of 194.5 months were retrospectively analysed. The risk ratios of morbidity and mortality of supine dominant OSA and non-supine OSA patients were compared.
  
  
  RESULTS
  Supine dominant OSA patients, having majority of the obstruction events occurring in supine position, showed higher mortality and morbidity risk ratios in severe OSA category than the non-supine OSA patients. In severe category, the observed risk ratios were statistically significant.
  
  
  CONCLUSIONS
  The increased risk ratios of mortality and morbidity found further emphasises that supine OSA might have more severe health consequences than non-positional OSA especially in severe OSA. Severe OSA occurring in supine position was shown to be more deleterious than non-supine OSA based on long-term mortality and morbidity evidence.
authors.affiliation: Department of Clinical Neurophysiology, Seinäjoki Central Hospital, 60220, Seinäjoki, Finland, antti.kulkas@epshp.fi.
authors.forename: Antti
authors.initials: A
authors.lastname: Kulkas
authors.forename: Anu
authors.initials: A
authors.lastname: Muraja-Murro
authors.forename: Pekka
authors.initials: P
authors.lastname: Tiihonen
authors.forename: Esa
authors.initials: E
authors.lastname: Mervaala
authors.forename: Juha
authors.initials: J
authors.lastname: Töyräs
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory; D017286:Polysomnography; D012189:Retrospective Studies; D020181:Sleep Apnea, Obstructive / Q000453:epidemiology*; D016683:Supine Position