Translation, cross-cultural adaptation, and measurement properties of the dysmenorrhea symptom interference (DSI) scale-Brazilian version

BACKGROUND: The Dysmenorrhea Symptom Interference (DSI) scale is a reliable, valid, and responsive tool to assess the interference of menstrual pain in the physical, mental, and social activities of women. OBJECTIVE: To translate and cross-culturally adapt the DSI scale into Brazilian-Portuguese (DSI-BrPt) and investigate the measurement properties of this version in on- and off-menses versions. METHODS: The original (United States) scale was translated and culturally adapted following existing guidelines. Measurement properties of the DSI-BrPt were investigated in 1387 women with dysmenorrhea. Reliability was analyzed via intraclass correlation coefficients (ICC) and test-retest reliability. Furthermore, structural validity, internal consistency (Cronbach's alpha), cross-cultural validity, construct validity (correlation with WHODAS 2.0 and SPS-6 scores questionnaires), and floor and ceiling effects were determined. RESULTS: No significant adaptations were needed during the translation process of the DSI-BrPt. The values of Cronbach's α were adequate (α ≥0.87) for the unidimensional scale. The test-retest reliability was considered adequate (ICC >0.78) and there was no systematic error for both on-menses and off-menses versions. Moreover, the DSI had a positive and strong correlation with WHODAS 2.0. There were no floor and ceiling effects neither for the total sample, nor among off-menses, or on-menses women. CONCLUSION: The DSI-BrPt scale has been translated and cross-culturally adapted successfully. The DSI-BrPt scale presented adequate measurement properties. The scale is valid and reliable, and, therefore, an adequate tool for monitoring dysmenorrhea symptoms in Brazilian women during and between menses.