Validation and Reliability of a Thai Version of the International Index of Erectile Dysfunction (IIEF) for Thai Population
Premsant Sangkum MD*, Chakrit Sukying MD**, Wit Viseshsindh MD*, Wachira Kochakarn MD*, Suthep Patcharatrakul MD*, Wisoot Khongcharoensombat MD*
Affiliation : * Division of Urology, Department of Surgery, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand ** Department of Psychiatry, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
Background : The International Index of Erectile Function 5 (IIEF5) is a standard questionnaire used for the evaluation of
men with erectile dysfunction (ED). The Thai language version of this questionnaire is still lacking.
Objective : To develop and validate the Thai version of the IIEF5 (IIEF5-Th) questionnaire for clinical use in the Thai
population.
Material and Method: The original IIEF5 questionnaire was translated into the Thai language by three experienced
urologists working independently. The final version of the IIEF5-Th was obtained after consensus was reached among the
three urologists and an experienced psychiatrist. The internal consistency and validity of this questionnaire was tested using
Cronbach’s alpha coefficient and the weighted kappa statistic (phase 1). The test-retest reliability was checked using the
intraclass correlation coefficient (ICC) for agreement (phase 2).
Results : Fifty participants with good knowledge of the English language enrolled in phase 1 and 123 participants enrolled in
phase 2 of the study. The IIEF5-Th demonstrated adequate internal consistency, with a Cronbach’s alpha of 0.99. There was
excellent agreement between the Thai and English versions of the IIEF5 questionnaire (weighted kappa >0.75), and the ICC
for test-retest reliability was 0.92.
Conclusion : The Thai version of the IIEF5 questionnaire has a high internal consistency, and it is a valid, reliable, and useful
tool for the evaluation of Thai men with ED.
Keywords : Erectile dysfunction, IIEF5, Questionnaire
