Translation and Cross-cultural Adaptation of the Orthognathic Quality-of-Life Questionnaire into the Malay language

Introduction: The Orthognathic Quality-of-Life Questionnaire (OQLQ) was developed in 2000 to assess the quality of life in patients with dentofacial deformities. The OQLQ has been translated into multiple languages and adapted to different cultures, but in Malaysia, there is no published translated version for the local population. The objectives of this study were to translate and cross-culturally adapt it, and to validate its usage in the Malaysian population. Methods: The translation process of OQLQ from the English version into the Malay version (OQLQ-M) was carried out via the forward-backward method. A total of 46 patients in the Oral and Maxillofacial Department, Hospital Tengku Ampuan Afzan, were recruited for this study from October 2022 to March 2023. The content validity of OQLQ-M was evaluated using the Content Validity Index (CVI). By pretesting the OQLQ-M with 10 participants of the study population, face validation was carried out. Concurrent validation was determined by comparing the OQLQ-M questionnaire to the shortened Oral Health Impact Profile (S-OHIP(M) questionnaire, which was represented by Spearman’s correlation coefficient. Reliability was tested using internal consistency using Cronbach’s alpha coefficient, and the test–retest method with a 2-week interval by measuring the intra-class coefficient correlation. Results: The overall response rate of the participants for this study was 95.65%. The content validity of OQLQ-M was validated through CVI with an overall scale (S-CVI) of 1.00. The OQLQ-M demonstrated excellent results in the internal consistency with a Cronbach’s alpha value of 0.964, and the test–retest reliability with the intra-class coefficient of 0.927 (95% confidence interval of 0.871–0.960, P < 0.001). Most of the components between OQLQ-M and S-OHIP(M) have low to moderate positive correlations when compared. Conclusion: The translated Malay version of the OQLQ is a reliable and valid tool to assess the quality of life in the Malaysian population with dentofacial deformities.