title: Role of hypothyroidism in obstructive sleep apnea: a meta-analysis.
abstract: This study evaluates the role of hypothyroidism in obstructive sleep apnea (OSA) by comparing the OSA indices in hypothyroid OSA (OSA-HYPOT) with euthyroid OSA (OSA-EUTHY) patients.
  
  
  
  After literature search in several electronic databases and selection of studies by following eligibility criteria, meta-analyses of mean differences/standardized mean differences were performed to compare OSA indices at the time of diagnosis between OSA-HYPOT and OSA-EUTHY patients. Metaregression analyses were carried out to examine the relationship between age, BMI, sample size, and gender vs OSA indices in OSA-HYPOT patients.
  
  
  
  Twelve studies and five case reports recruiting 192 OSA-HYPOT and 1423 OSA-EUTHY patients were included in the meta-analysis. Prevalence (mean ± SD) of clinical hypothyroidism in OSA patients was 8.12 ± 7.13% and that of subclinical hypothyroidism 11.07 ± 8.49%. Apnea-Hypopnea Index, time of sleep with oxygen desaturation <90%, and Epworth Sleepiness Scale were significantly higher in the OSA-HYPOT patients at diagnosis, whereas there was no significant difference in arousal index, respiratory disturbance index and sleeping efficiency between OSA-HYPOT and OSA-EUTHY patients. Body mass index was positively associated with Apnea-Hypopnea Index in OSA-HYPOT patients.
  
  
  
  Hypothyroidism is found to be associated with severity of OSA. However, obesity can be a confounder in the outcomes observed herein.
authors.affiliation: a Department of Geriatrics , Tianjin Medical University General Hospital, Tianjin Geriatrics Institute , Tianjin , China.
authors.forename: Mingpeng
authors.initials: M
authors.lastname: Zhang
authors.affiliation: a Department of Geriatrics , Tianjin Medical University General Hospital, Tianjin Geriatrics Institute , Tianjin , China.
authors.forename: Weisan
authors.initials: W
authors.lastname: Zhang
authors.affiliation: a Department of Geriatrics , Tianjin Medical University General Hospital, Tianjin Geriatrics Institute , Tianjin , China.
authors.forename: Jin
authors.initials: J
authors.lastname: Tan
authors.affiliation: a Department of Geriatrics , Tianjin Medical University General Hospital, Tianjin Geriatrics Institute , Tianjin , China.
authors.forename: Minghui
authors.initials: M
authors.lastname: Zhao
authors.affiliation: a Department of Geriatrics , Tianjin Medical University General Hospital, Tianjin Geriatrics Institute , Tianjin , China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: a Department of Geriatrics , Tianjin Medical University General Hospital, Tianjin Geriatrics Institute , Tianjin , China.
authors.forename: Ping
authors.initials: P
authors.lastname: Lei
mesh_terms: D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000150:complications*; D008297:Male; D009765:Obesity / Q000150:complications*; D015995:Prevalence; D012890:Sleep; D020181:Sleep Apnea, Obstructive / Q000453:epidemiology* / Q000209:etiology
keywords: Apnea; epworth sleepiness scale; hormonal replacement therapy; hypopnea index; hypothyroidism; obstructive sleep apnea