Translation, cross-cultural adaptation, and validation of the Thai version of the Hot Flash–related Daily Interference Scale (Thai HFRDIS)

OBJECTIVE: To translate, culturally adapt, and validate the Thai Hot Flash-related Daily Interference Scale for assessing interference from vasomotor symptoms. METHODS: In this cross-sectional psychometric validation study, the Hot Flash-related Daily Interference Scale was translated using forward-backward translation, expert review, and cognitive debriefing. Women in the menopause transition or postmenopause at the menopause clinic in Bangkok completed the Thai Hot Flash-related Daily Interference Scale, the Thai Menopause Rating Scale, and the Thai Menopause-Specific Quality of Life questionnaire. Psychometric evaluation included content validity, structural validity, internal consistency, test-retest reliability using the intraclass correlation coefficient, construct validity evidence, floor and ceiling effects, and exploratory receiver operating characteristic analyses to support score interpretation. RESULTS: Of 336 enrolled women, 330 were analyzed (164 symptomatic and 166 asymptomatic controls). Content validity was high (scale-level content validity index=0.960). Reliability was excellent (Cronbach's alpha=0.963; intraclass correlation coefficient=0.981; 95% CI: 0.971-0.987). Factor analyses supported a predominantly unidimensional structure. Construct validity evidence was supported by a strong correlation with the vasomotor domain of the Thai Menopause-Specific Quality of Life Questionnaire (Spearman's correlation coefficient=0.716; P<0.001) and by known-groups differences between symptomatic and asymptomatic women (mean, 3.67 vs. 0.43; P<0.001). In exploratory supplementary analyses, scale scores showed good discrimination between Menopause Rating Scale-defined symptom-burden groups. CONCLUSION: The Thai Hot Flash-related Daily Interference Scale demonstrated reliability and validity and provides a brief measure of vasomotor symptom-related interference for Thai-speaking women in clinical practice and research.