title: Cross-cultural adaptation and validation of the Greek OSA-18 questionnaire in children undergoing polysomnography.
abstract: OBJECTIVE
  Translations of validated questionnaires help to compare different countries/cultures populations and establish protocols for global health. OSA-18 is a validated disease-specific questionnaire for pediatric Obstructive Sleep Apnea (OSA). Our aim was to validate OSA-18 in Greek and correlate it with polysomnography results and OSA severity.
  
  
  METHODS
  Prospective instrument validation study.
  
  
  METHODS
  OSA-18 was translated in Greek and back into English. Children undergoing polysomnography due to snoring were recruited prospectively. OSA-18 was completed by parents during the initial clinic visit (test), in the evening prior to the sleep study (retest), and 3 months postoperatively for subjects who underwent adenotonsillectomy. Internal consistency and test-retest reliability were evaluated. Validity was assessed by exploring correlations between OSA-18 and AHI, by comparing OSA-18 of OSA and non-OSA groups, and by calculating questionnaire's sensitivity and specificity for detecting OSA. Total scores of non-OSA, mild, moderate and severe OSA subgroups were compared. In OSA children who underwent adenotonsillectomy, preoperative and postoperative total scores were compared to assess responsiveness.
  
  
  RESULTS
  Test-retest questionnaires were fully completed for 141 children. OSA-18 in Greek had good internal consistency (Cronbach's alpha 0.951 for test and 0.947 for retest) and test-retest reliability (Pearson's correlation coefficients between test and retest scores: 0.850-0.946; P<0.05). Total and subscale OSA-18 scores and AHI were significantly correlated (Spearman's correlation coefficients: 0.376-0.633; P<0.01), while children with OSA had higher total OSA-18 score than those without OSA [median (interquartile range): 61 (35) vs. 38 (22), respectively; P<0.001)]. Sensitivity was 53.4%, suggesting poor validity compared to polysomnography. All OSA severity subgroups had significant higher score than non-OSA. OSA-18 scores postoperatively were significantly lower compared to preoperatively (22.91±5.49 vs. 67.13±15.27, respectively; P<0.001), indicating good responsiveness.
  
  
  CONCLUSIONS
  Greek OSA-18 is an instrument with satisfactory internal consistency, reliability, and responsiveness, but it is a poor predictor of OSA severity.
authors.affiliation: Department of Otorhinolaryngology, University Hospital of Larissa, Greece.
authors.forename: George K
authors.initials: GK
authors.lastname: Mousailidis
authors.affiliation: Department of Otorhinolaryngology, University Hospital of Larissa, Greece. Electronic address: vlachanas@gmail.com.
authors.forename: Vasileios A
authors.initials: VA
authors.lastname: Lachanas
authors.affiliation: Department of Otorhinolaryngology, University Hospital of Larissa, Greece.
authors.forename: Charalampos E
authors.initials: CE
authors.lastname: Skoulakis
authors.affiliation: Department of Otorhinolaryngology, University Hospital of Larissa, Greece.
authors.forename: Achilles
authors.initials: A
authors.lastname: Sakellariou
authors.affiliation: Department of Otorhinolaryngology, University Hospital of Larissa, Greece.
authors.forename: Sotirios T
authors.initials: ST
authors.lastname: Exarchos
authors.affiliation: Sleep Disorders Laboratory, University Hospital of Larissa, Greece; Pediatric Pulmonology Unit and Sleep Disorders Laboratory, First Department of Pediatrics, University of Athens School of Medicine and Aghia Sophia Children's Hospital, Athens, Greece.
authors.forename: Athanasios G
authors.initials: AG
authors.lastname: Kaditis
authors.affiliation: Department of Otorhinolaryngology, University Hospital of Larissa, Greece.
authors.forename: John G
authors.initials: JG
authors.lastname: Bizakis
mesh_terms: D000233:Adenoidectomy; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006115:Greece; D006801:Humans; D008297:Male; D017286:Polysomnography; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000601:surgery; D012913:Snoring / Q000209:etiology; D011795:Surveys and Questionnaires; D014068:Tonsillectomy; D014175:Translating
keywords: Greek; OSA; OSA-18; Pediatric obstructive sleep apnea; Polysomgography