title: Is obstructive sleep apnoea syndrome really one of the causes of secondary polycythaemia?
abstract: BACKGROUND
  It is widely believed that sleep apnoea syndrome leads to polycythaemia, but the evidence is largely anecdotal. We believe that polycythaemia is not commonly seen in patients with sleep apnoea syndrome. Therefore, we aimed to determine the relationship between polycythaemia and sleep apnoea syndrome.
  
  
  METHODS
  The study included 335 patients diagnosed with obstructive sleep apnoea (OSA) syndrome, all of whom underwent standard nocturnal polysomnography.
  
  
  RESULTS
  There were no significant differences in haemoglobin levels or haematocrit (P > 0.05) between the OSA groups in all patients. Of the 335 patients, only 1 male patient with severe OSA (0.3%) had clinically significant polycythaemia. According to regression analysis, there was a weak linear correlation between haemoglobin levels and lowest oxygen saturation levels in female patients (r = -0.242, P = 0.021).
  
  
  CONCLUSIONS
  We think that OSA is very rarely the reason for secondary polycythaemia.
authors.forename: Soner
authors.initials: S
authors.lastname: Solmaz
authors.forename: Faysal
authors.initials: F
authors.lastname: Duksal
authors.forename: Sencer
authors.initials: S
authors.lastname: Ganidağlı
mesh_terms: D000328:Adult; D001772:Blood Cell Count; D003430:Cross-Sectional Studies; D004912:Erythrocytes / Q000502:physiology; D005260:Female; D006400:Hematocrit; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D011086:Polycythemia / Q000097:blood / Q000175:diagnosis* / Q000503:physiopathology; D017286:Polysomnography; D012189:Retrospective Studies; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000097:blood / Q000175:diagnosis* / Q000503:physiopathology
chemical_list: D006454:Hemoglobins
keywords: Erythrocytosis; Intermittent hypoxaemia; Obstructive sleep apnoea syndrome; Polycythaemia