Daily diary-based dysmenorrhea and nonmenstrual pelvic pain impact items were developed and validated to measure efficacy in endometriosis clinical trial settings. Items were developed across 3 stages of qualitative research, and their psychometric properties were explored in a phase II randomized controlled trial. Eight focus groups, 20 semistructured telephone interviews, and 15 face-to-face concept elicitation and cognitive debriefing interviews constituted the qualitative phase of the research. Psychometric properties of reliability, convergent validity, and responsiveness of the dysmenorrhea and nonmenstrual pelvic pain daily items were examined quantitatively in a phase II clinical trial of an investigational endometriosis treatment. Both qualitative concept elicitation and cognitive debriefing research yielded wording for item response options that resonated with adult women with endometriosis. Daily assessment of dysmenorrhea and nonmenstrual pelvic pain impact was the preferred measurement approach among adult women with endometriosis. Quantitatively, correlations between the dysmenorrhea and nonmenstrual pelvic pain items and other measures of pain impact provided endorsement for the items' convergent validity. Longitudinal measurement properties, involving test-retest reliability and sensitivity to change/responsiveness, offered evidence for the adequacy of the measurement properties of the daily diary-based dysmenorrhea and nonmenstrual pelvic pain impact items. Data from a phase II trial provided evidence that the daily dysmenorrhea and nonmenstrual pelvic pain impact items, developed and tested through qualitative research involving both focus groups and individual interviews, are well-defined, reliable, valid, and responsive for measuring the impact of pain in endometriosis to assess therapeutic response.
Keywords: dysmenorrhea; endometriosis; nonmenstrual pelvic pain; pain; patient-reported outcomes.