Background: The aim of this study was to validate the Farsi version of Rome III modular questionnaire which contains all functional gastrointestinal disorders (FGIDs).
Materials and methods: We used Rome foundation guidelines for translation of English version into Farsi, and all the steps were performed. In the first step, 2 forward translations into Farsi were completed by two authors separately, and then translators, who participated in Step 1, together with our monitor, compared the two target-language versions and made some changes. The product of Phase 2 was translated back into English by an American-Iranian physician. The final step was comparison of the two English versions and validation of the translation. In this step, we compared the final version item by item, and also we used focus groups of patients after pretesting.
Results: Our results showed that FGIDs questionnaire diagnosed 153 patients among 169 patients who were diagnosed to have different types of FGIDs. The sensitivity of this questionnaire was 90.5%. It was determined that the odd questions' values of Cronbach's alpha was 0.77 (very reliable), and it was 0.71 (very reliable) in other sections. The split-half test reliability of whole items value was 0.72, which is statistically significant.
Conclusion: Our findings showed that the Farsi version of Rome III diagnostic questionnaire for the adult functional gastrointestinal disorders demonstrated good validity and reliability and could be used in clinical studies.
Keywords: Farsi; Iran; Rome III criteria; functional gastrointestinal disorders; validity.