title: Severity of individual obstruction events is gender dependent in sleep apnea.
abstract: OBJECTIVE
  In obstructive sleep apnea (OSA), severity of individual obstruction events is connected to increased mortality rate and it can be significantly different in patients with similar apnea-hypopnea index (AHI). However, possible gender-dependent variation in severity of obstruction events in different OSA categories is unknown. We investigated whether the severity of obstruction events differs between genders with similar AHI and if this difference varies between OSA categories.
  
  
  METHODS
  Polygraphic recordings of 2057 consecutive patients with suspected OSA were reanalyzed and those with AHI ≥5/h were included for further analysis (nmale= 893 and nfemale= 197). Statistical significance of differences in AHI, apnea index, hypopnea index, oxygen desaturation index, obstruction severity parameter, and severity of individual obstruction events between genders were evaluated using the Mann-Whitney U (MWU) test as well as the general linear model (GLM) univariate analysis adjusted for age, BMI, smoking, daytime sleepiness, snoring, and heart failure.
  
  
  RESULTS
  Apneas were 16.9 and 19.6% longer (MWU p ≤ 0.015, GLM p ≤ 0.036) and desaturation areas were 15.4 and 23.7% larger (MWU p ≤ 0.024, GLM p ≤ 0.053) in males compared to females with moderate and severe OSA, respectively. In contrast, hypopneas were 9.1% shorter (MWU p = 0.001, GLM p ≤ 0.001) and desaturation areas were 6.0% smaller (MWU p = 0.114, GLM p = 0.025) in men with mild OSA. The apnea index was 433.3 and 313.1% higher (MWU p ≤ 0.001, GLM p ≤ 0.043) and the hypopnea index was 12.2 and 17.8% lower (MWU p ≤ 0.001, GLM p = 0.002, p = 0.083) in males with mild and moderate OSA, respectively.
  
  
  CONCLUSIONS
  As severity of individual obstruction events was significantly different in males and females, the overall severity of OSA may not be similar despite the similarity in AHI.
authors.affiliation: Department of Clinical Neurophysiology, Kuopio University Hospital, P.O Box 100, 70029, Kuopio, Finland. timole@student.uef.fi.|Department of Applied Physics, University of Eastern Finland, Kuopio, Finland. timole@student.uef.fi.
authors.forename: Timo
authors.identifier: http://orcid.org/0000-0003-4017-821X
authors.initials: T
authors.lastname: Leppänen
authors.affiliation: Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.|Department of Clinical Neurophysiology, Seinäjoki Central Hospital, Seinäjoki, Finland.
authors.forename: Antti
authors.initials: A
authors.lastname: Kulkas
authors.affiliation: Sleep Disorders Centre, Department of Respiratory and Sleep Medicine, Princess Alexandra Hospital, Brisbane, Australia.|Faculty of Science and Engineering, Queensland University of Technology, Brisbane, Australia.
authors.forename: Brett
authors.initials: B
authors.lastname: Duce
authors.affiliation: Department of Clinical Neurophysiology, Kuopio University Hospital, P.O Box 100, 70029, Kuopio, Finland.|Institute of Clinical Medicine, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland.
authors.forename: Esa
authors.initials: E
authors.lastname: Mervaala
authors.affiliation: Department of Clinical Neurophysiology, Kuopio University Hospital, P.O Box 100, 70029, Kuopio, Finland.|Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Töyräs
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012720:Severity of Illness Index; D012737:Sex Factors; D020181:Sleep Apnea, Obstructive / Q000145:classification* / Q000175:diagnosis* / Q000401:mortality; D015996:Survival Rate
keywords: Duration; Female; Gender; Obstruction severity; Obstructive sleep apnea; Women