Validation of the Greek OSD-6 quality of life questionnaire in children undergoing polysomnography

Objective: OSD-6 is a disease specific questionnaire for pediatric obstructive sleep apnea (OSA). The aims of this study were to validate OSD-6 in Greek language and correlate OSD-6 with polysomnography results.

Study design: Prospective study.

Setting: Tertiary referral center.

Subjects and methods: OSD-6 questionnaire was translated to Greek and back to English. A prospective study was conducted on children undergoing overnight polysomnography due to snoring and disrupted sleep. Test-retest evaluation was carried out. Internal consistency and test-retest reliability were evaluated. Validity was assessed by exploring correlations between OSD-6 scores and apnea-hypopnea index (AHI), and by comparing total scores of OSA and non-OSA groups. Responsiveness was assessed by comparing preoperative to postoperative total scores in OSA children who underwent adenotonsillectomy.

Results: Test-retest evaluation of 91 subjects showed good internal consistency (Cronbach's alpha 0.860 for test and 0.873 for retest) and reliability (Pearson's correlation coefficients between test and retest scores: 0.751-0.546; p<0.01). Total and domains' OSD-6 scores and AHI were significantly correlated (Spearman's correlation coefficients: 0.277-0.630; p<0.01), while children with OSA had higher total OSD-6 score than those without OSA (median (interquartile range): 16 (11) vs. 10 (7), respectively; p<0.01), indicating good validity. Postoperative OSD-6 scores were significantly lower than preoperative (2.84 ± 3.21 vs. 15.42 ± 6.48, respectively; p<0.001), suggesting good responsiveness.

Conclusion: The Greek version of the OSD-6 questionnaire proved to be a valid instrument with satisfactory internal consistency, reliability, validity and responsiveness. Furthermore, in our study OSD-6 was significantly correlated to polysomnography results.