Reliability and validity of the Turkish version of myasthenia gravis-quality of life questionnaire-15 item

Abstract

Background/aim: The myasthenia gravis-quality of life questionnaire 15 item (MG-QOL15) is a validated, short, and easy to use disease-specific quality of life (QOL) tool in myasthenia gravis. Other than Turkish, a lot of versions of the MG-QOL15 have been used in different languages in different cultures. Therefore, the aim of this study was to translate and construct a validated and adapted Turkish version of the MG-QOL15 [ MG-QOL15(T)]. Materials and methods: After translation, back-translation, and comparison of the 2 English versions of the MG-QOL15, it was tested by 22 monolingual healthy individuals and then 23 patients with clinically stable MG. Afterwards, 11 voluntary patients out of these 23 patients were interviewed for a second time. During the second interview, the MG-QOL15(T) and the 36-item short-form health survey (Turkish version) were administered simultaneously. Results: The MG-QOL15(T) was found to have high internal consistency (1st and 2nd evaluation Cronbach's alphas were 0.958 and 0.928, respectively), test-retest reliability, and concurrent validity. The MG-QOL15(T) was negatively correlated with physical functioning, general health, vitality, and social functioning domains and with the physical and mental composite scores of the SF-36. Conclusion: The MG-QOL15(T) is accepted to be a valid, reliable, valuable tool for measuring disease-specific QOL in Turkish patients with MG.