title: C-reactive Protein as a Potential Biomarker of Residual Obstructive Sleep Apnea Following Adenotonsillectomy in Children.
abstract: OBJECTIVE
  Adenotonsillectomy (AT) is first-line treatment for pediatric obstructive sleep apnea (OSA), with most children having improvements in polysomnography (PSG). However, many children have residual OSA following AT as determined through PSG. Identification of a biomarker of residual disease would be clinically meaningful to detect children at risk. We hypothesize serum high-sensitivity C-reactive protein (hsCRP), an inflammatory biomarker, is predictive of residual OSA following AT.
  
  
  METHODS
  PSG was performed both preoperatively and postoperatively on children undergoing AT for the diagnosis of OSA. HsCRP serum concentrations were determined in all children pre-AT, and in most children post-AT. Resolution of OSA after AT was defined by a post-AT apnea-hypopnea index (AHI) < 1.5/h total sleep time (TST). Residual OSA was defined as a post-AT AHI > 5/h TST, which is considered clinically significant.
  
  
  RESULTS
  AT significantly improved the AHI from 15.9 ± 16.4 to 4.1 ± 5.3/h TST in 182 children (P < 0.001). Of 182 children, residual OSA (post-AT AHI > 5) was seen in 46 children (25%). Among children who had hsCRP levels measured pre- and post-AT (n = 155), mean hsCRP levels pre-AT were 0.98 ± 1.91 mg/L and were significantly reduced post-AT (0.63 ± 2.24 mg/dL; P = 0.011). Stratification into post-AT AHI groups corresponding to < 1.5/h TST, 1.5/h TST < AHI < 5/h TST, and AHI > 5/h TST revealed post-AT hsCRP levels of 0.09 ± 0.12, 0.57 ± 2.28, and 1.49 ± 3.34 mg/L with statistical significance emerging comparing residual AHI > 5/h TST compared to post-AT AHI < 1.5/h TST (P = 0.006). Hierarchical multivariate modeling confirmed that pre-AT AHI and post-AT hsCRP levels were most significantly associated with residual OSA.
  
  
  CONCLUSIONS
  Even though AT improves OSA in most children, residual OSA is frequent. Assessment of post-AT hsCRP levels emerges as a potentially useful biomarker predicting residual OSA.
authors.affiliation: Sections of Pediatric Sleep Medicine, Department of Pediatrics, Comer Children's Hospital, The University of Chicago, Chicago, IL.|Pediatric Pulmonology, Department of Pediatrics, Comer Children's Hospital, The University of Chicago, Chicago, IL.
authors.forename: Rakesh
authors.initials: R
authors.lastname: Bhattacharjee
authors.affiliation: Sections of Pediatric Sleep Medicine, Department of Pediatrics, Comer Children's Hospital, The University of Chicago, Chicago, IL.
authors.forename: Leila
authors.initials: L
authors.lastname: Kheirandish-Gozal
authors.affiliation: Sleep Disorders Laboratory, University of Thessaly School of Medicine and Larissa University Hospital, Larissa, Greece.
authors.forename: Athanasios G
authors.initials: AG
authors.lastname: Kaditis
authors.affiliation: Department of Pediatrics, University of Antwerp, Wilrijk, Belgium.
authors.forename: Stijn L
authors.initials: SL
authors.lastname: Verhulst
authors.affiliation: Sections of Pediatric Sleep Medicine, Department of Pediatrics, Comer Children's Hospital, The University of Chicago, Chicago, IL.|Pediatric Pulmonology, Department of Pediatrics, Comer Children's Hospital, The University of Chicago, Chicago, IL.
authors.forename: David
authors.initials: D
authors.lastname: Gozal
mesh_terms: D000233:Adenoidectomy; D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D002097:C-Reactive Protein / Q000032:analysis / Q000378:metabolism*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D017286:Polysomnography; D011184:Postoperative Period; D012306:Risk; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D014068:Tonsillectomy
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein
keywords: adenotonsillectomy; biomarker; c-reactive protein; children; obstructive sleep apnea; residual disease