Dysmenorrhea-Related Impact on Functioning Scale: Development and Measurement Properties for Cisgender Women and Transgender Men

Objectives To develop the Dysmenorrhea-related Impact on Functioning Scale (DIFS) to assess the impact of dysmenorrhea on functioning in cisgender women and transgender men and to evaluate its measurement properties. Methods Mixed and online design study conducted with adolescents and adult cisgender women and transgender men with dysmenorrhea. We developed the DIFS based on the International Classification of Functioning, Disability, and Health. Content validity was assessed with experts and people with dysmenorrhea. Item Response Theory developed the DIFS total score. Structural validity was assessed by exploratory and confirmatory factor analysis and internal consistency by Cronbach’s α and McDonald’s Ω. Construct validity and test-retest reliability were assessed by correlation between DIFS and World Health Organization Disability Assessment Schedule and intraclass correlation coefficient, respectively. Measurement error was also assessed. Results A total of 3335 people participated in the study. The DIFS is a 15-item instrument divided into “Bodily Functions” and “Daily Activities and Social Participation” sections and “Functioning” as a general factor. Internal consistency (α and Ω > 0.7) and test-retest reliability (intraclass correlation coefficient > 0.9) were adequate. No systematic error was found. Correlation was positive and strong between World Health Organization Disability Assessment Schedule and “Functioning” (r = 0.62, P ≤ .05). For the DIFS total score, higher scores indicate a greater impact of dysmenorrhea on functioning, and 44 points is the cutoff point for classifying the person with a significant impact of dysmenorrhea on functioning. Conclusions DIFS showed excellent measurement properties for assessing the impact of dysmenorrhea on functioning for cisgender women and transgender men.