Psychometric properties of the Lithuanian version of Sleep Apnea Quality of Life Index (a pilot study)

Objective. To arrange and test for its psychometric properties Lithuanian version of Sleep Apnea Quality of Life Index and assess quality of life among snoring and obstructive sleep apnea patients before and after the treatment.
Material and methods. Cross-cultural adaptation of Lithuanian version of Calgary Sleep Apnea Quality of Life Index was accomplished according to generally accepted methodology. In total, 36 (29 males and 7 females) patients (mean age, 41.1±9.7 years) suffering from socially disturbing snoring and obstructive sleep apnea were included into the study. All patients underwent complete full-night polysomnography (mean apnea/hypopnea index, 12.7±11.2) and were treated with two sessions of radiofrequency tissue ablation at the palatal and tong base (if it was necessary) levels. Lithuanian version of the Calgary Sleep Apnea Quality of Life Index was presented before the treatment with radiofrequency tissue ablation and in the period of 2 to 3 months after the treatment. Thirty-five patients repeated the same questionnaire after three weeks to assess the reliability of scores.
Results. The Cronbach’s α coefficients of internal reliability were above the standard (0.7 for groups) in all subdomains and domains. Test-retest correlation coefficients for each domain (ranged from 0.92 to 0.94) were statistically significant (P<0.0001). Lithuanian version of the questionnaire was found to be responsive to clinical change. A statistically significant difference in the mean Sleep Apnea Quality of Life Index scores in the study group patients before and after the surgery was found in all daily functioning subdomains and social interactions domains.
Conclusions. Overall, the results of the present pilot study demonstrate that the Lithuanian version of Sleep Apnea Quality of Life Index is applicable for clinical purposes.