title: The prevalence and natural history of complex sleep apnea.
abstract: BACKGROUND
  Central sleep apnea (CSA) may occasionally occur in patients with obstructive sleep apnea during titration with a continuous positive airway pressure (CPAP) device.
  
  
  OBJECTIVE
  To determine the prevalence and the natural history of CPAP-emergent CSA.
  
  
  METHODS
  This is a retrospective study of 1286 patients with a diagnosis of OSAwho underwent titration with a positive airway device during a 1-year period. Patients were seen in consultation and underwent full-night attended polysomnography followed by full-night attended CPAP titration. Four weeks after CPAP therapy, patients returned to the clinic for follow-up, and objective adherence to CPAP was recorded. In patients who had CSA on CPAP, a second full-night attended CPAP titration was recommended.
  
  
  RESULTS
  Eighty-four of the 1286 patients developed a central apnea index (CAI) of 5 or greater per hour while on CPAP. The incidence of CSA varied from 3% to 10% monthly, with an overall incidence of 6.5%. Forty-two of the 84 patients returned for a second CPAP titration. In 33 patients, CSA was eliminated. In each of the remaining 9 patients, the CAI remained at 5 or greater per hour, with an average of 13 per hour. These patients characteristically had the most severe OSA, and 5 had a CAI of 5 or more per hour at baseline. Two of the 9 patients were on opioids
  
  
  CONCLUSIONS
  In this large retrospective study of 1286 patients with a diagnosis of OSA, 6.5% had CPAP-emergent or persistent CSA. However, CPAP-emergent CSA was generally transitory and was eliminated within 8 weeks after CPAP therapy. The prevalence of CPAP-persistent CSA was about 1.5%. Severity of OSA, a CAI of 5 or greater per hour, and use of opioids were potential risk factors.
authors: Sleepcare Diagnostics, Christ Hospital, Cincinnati, OH 45040, USA. Javaheri@snorenomore.com
authors: Shahrokh
authors: S
authors: Javaheri
authors: Jason
authors: J
authors: Smith
authors: Eugene
authors: E
authors: Chung
mesh_terms: D045422:Continuous Positive Airway Pressure / Q000379:methods; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000706:statistics & numerical data; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000453:epidemiology* / Q000628:therapy