title: Polysomnographic findings after adenotonsillectomy for obstructive sleep apnoea in obese and non-obese children: a systematic review and meta-analysis.
abstract: BACKGROUND
  Use of polysomnography (PSG) is the gold standard of diagnosis and measurement of treatment effectiveness for paediatric obstructive sleep apnoea (OSA). Although adenotonsillectomy (T&A) is effective in diminishing the apnoea-hypopnoea index (AHI), a meta-analysis of postoperative changes for all other PSG parameters and outcome comparisons between obese and non-obese children following T&A have never been conducted.
  
  
  OBJECTIVE
  To comprehensively review polysomnographic findings after surgery for obese and non-obese children with OSA.
  
  
  METHODS
  Study protocol was registered on PROSPERO (CRD42013004737). Two authors independently searched databases including PubMed, MEDLINE, EMBASE and Cochrane Review from January 1997 to July 2014. The keywords used included the following: sleep apnea, OSA, sleep apnea syndromes, tonsillectomy, adenoidectomy, infant, child, adolescent, and Humans.
  
  
  METHODS
  A comprehensive systematic review and meta-analysis for literature for OSA children treated by T&A with polysomnography data. Random-effects model was applied to determine postoperative sleep parameter changes and the surgical success rate between obese and non-obese groups. The quality of studies was assessed using the Newcastle-Ottawa Scale.
  
  
  RESULTS
  In total, 51 studies with 3413 subjects were enrolled. After surgery, sleep architecture was altered by a significant decrease in sleep stage 1, and an increase in slow-wave sleep and the rapid eye movement stage, and enhanced sleep efficiency. The mean difference between pre- and postoperative was a significant reduction of 12.4 event/h in AHI, along with a reduction of obstructive index, hypopnoea index, central index and arousal index. Mean and minimum oxygen saturation increased significantly after surgery. The overall success rate was 51% for postoperative AHI <1 (obese versus non-obese versus combined, 34% versus 49% versus 56%), and 81% for AHI <5 (obese versus non-obese versus combined, 61% versus 87% versus 84%). Meta-regression analyses demonstrate that postoperative AHI was positively correlated with AHI and body mass index z score before surgery.
  
  
  CONCLUSIONS
  Meta-analysis of current literature shows T&A offers prominent improvement in a variety of sleep parameters. Improvements in non-obese children exceeded those for obese children. Postoperative residual OSA remained in roughly half of the children, especially those with severe disease and obesity, making additional treatment strategies and/or long-term follow-up highly desirable.
authors.affiliation: Department of Otolaryngology, Taipei Hospital, Ministry of Health and Welfare, New Taipei City, Taiwan.|Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan.
authors.forename: C-H
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Sleep Center, National Taiwan University Hospital, Taipei, Taiwan.|Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: W-C
authors.initials: WC
authors.lastname: Hsu
authors.affiliation: Department of Otolaryngology, Taipei Hospital, Ministry of Health and Welfare, New Taipei City, Taiwan.|Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan.|College of Medicine, Fu Jen Catholic University, Taipei, Taiwan.
authors.forename: W-H
authors.initials: WH
authors.lastname: Chang
authors.affiliation: Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan. lightpool2010@gmail.com.|Sleep Center, National Taiwan University Hospital, Taipei, Taiwan. lightpool2010@gmail.com.|Department of Internal Medicine, Hsiao Chung-Cheng Hospital, New Taipei City, Taiwan. lightpool2010@gmail.com.
authors.forename: M-T
authors.initials: MT
authors.lastname: Lin
authors.affiliation: Department of Otolaryngology, Taipei Hospital, Ministry of Health and Welfare, New Taipei City, Taiwan. kang.kuntai@msa.hinet.net.|Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan. kang.kuntai@msa.hinet.net.|Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan. kang.kuntai@msa.hinet.net.
authors.forename: K-T
authors.initials: KT
authors.lastname: Kang
mesh_terms: D000233:Adenoidectomy; D002648:Child; D006801:Humans; D063766:Pediatric Obesity / Q000150:complications*; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000209:etiology* / Q000601:surgery*; D014068:Tonsillectomy; D016896:Treatment Outcome