title: Predictors and patterns of insomnia symptoms in OSA before and after PAP therapy.
abstract: OBJECTIVE
  Identify factors that predict improvement versus persistence of insomnia symptoms following treatment of obstructive sleep apnea (OSA) with positive airway pressure (PAP) therapy.
  
  
  METHODS
  Archival data from 68 PAP-treated sleep apnea patients aged 25-83 were analyzed using nonparametric tests and stepwise regression to assess the relationships between insomnia symptoms, multiple OSA variables, and PAP use over time.
  
  
  RESULTS
  Pretreatment insomnia symptom severity (ISS; b = -0.72, p < 0.001), PAP average use (b = -0.01, p = 0.01) and respiratory disturbance index (RDI; b = -0.02, p = 0.03) predict change in insomnia following PAP therapy. Forty-five percent (24/53) of the subjects with moderate to severe insomnia at pretreatment reported no/mild symptoms after PAP therapy and were considered improved. Improved subjects had lower pretreatment ISS (p < 0.001), higher RDI (p = 0.01), and higher average PAP use (p < 0.035) than subjects with persistent insomnia. Number of medications and comorbidities were similar between improved and persistent groups. New onset of insomnia symptoms occurred in 13% (2/15) of the patients with no/mild pretreatment insomnia.
  
  
  CONCLUSIONS
  Although ISS declines following PAP treatment, 55% of OSA patients have persistent moderate to severe symptoms despite treatment. More severe OSA is linked to higher likelihood of insomnia improvement and the effect of PAP therapy on insomnia may be mediated by OSA severity. Persistent insomnia is unrelated to medication use or comorbidities and may represent an independent, self-sustaining disorder requiring targeted intervention.
authors.affiliation: Lynn Institute for Healthcare Research, Colorado Springs, CO, USA. Electronic address: robert@sleeplivework.com.
authors.forename: Robert N
authors.initials: RN
authors.lastname: Glidewell
authors.affiliation: University of Colorado, Colorado Springs, CO, USA.
authors.forename: Brenna N
authors.initials: BN
authors.lastname: Renn
authors.affiliation: Lynn Institute for Healthcare Research, Colorado Springs, CO, USA.
authors.forename: Emily
authors.initials: E
authors.lastname: Roby
authors.affiliation: Lynn Institute for Healthcare Research, Oklahoma City, OK, USA; University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Lynn Institute for Healthcare Research, Colorado Springs, CO, USA.
authors.forename: William C
authors.initials: WC
authors.lastname: Orr
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D045422:Continuous Positive Airway Pressure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000628:therapy*; D007319:Sleep Initiation and Maintenance Disorders / Q000209:etiology* / Q000628:therapy; D016896:Treatment Outcome
keywords: Apnea–hypopnea index (AHI); Comorbidity; Insomnia; Insomnia Severity Index (ISI); Positive air pressure (PAP); Respiratory disturbance index (RDI); Sleep apnea