Hot Flash-Related Daily Interference Scale Short Form

Purpose: The Hot Flash Related Daily Interference scale (HFRDIS) is a widely used, psychometrically sound, 10-item, self-report questionnaire assessing the impact of hot flashes, a cardinal symptom of menopause, on a woman’s life. The scale has been translated to 12 languages, cited over 150 times in journal articles and textbooks, and was included as an outcome measure within the National Cancer Institute Physician Data Query Cancer Information Summaries for Supportive and Palliative Care (Coping with Cancer). The HFRDIS is sensitive to change over time and documented reductions in interference have been observed with pharmacologic treatments, dietary supplements, and behavioral therapies. Because a shorter version may be desirable in certain situations and because cutpoints and minimally important differences have not previously been established, this study aimed to address those gaps. Our purposes were to shorten the HFRDIS into a shorter form termed the Hot Flash Interference (HFI) scale, establish cutpoints for both scales, and establish minimally important differences for both scales using psychometric analyses.

Methods:  We analyzed baseline and post-randomization patient-reported data pooled across three randomized trials aimed at reducing hot flashes in 899 midlife women. Trials were conducted across five clinical sites between July 2009 and October 2012 as part of a United States National Institutes of Health funded research network. We eliminated HFRDIS items based on experts’ content validity ratings and confirmatory factor analysis. We established cutpoints and minimally important differences by mapping HFRDIS and HFI to symptom and quality of life measures including daily diary-reported hot flashes, the Menopause Quality of Life Scale, Pittsburgh Sleep Quality Index, Insomnia Severity Index, and Generalized Anxiety Disorders-7 questionnaire.

Results:  The short HFI consisted of 3 items related to interference with sleep, mood, and concentration. The HFI demonstrated strong internal consistency (alphas of 0.830 and 0.856), showed good fit to the unidimensional “hot flash interference factor”, and strong convergent validity with HFRDIS scores, diary-recorded hot flashes, and menopausal quality of life. For both scales, cutpoints of mild (0–3.9), moderate (4–6.9), and severe (7–10) were associated with increasing sleep and anxiety problems as expected. The average minimally important difference for HFRDIS was 1.66 and for HFI it was 2.34.

Conclusion:  The HFI is a brief assessment tool that will be useful in busy clinical practices to standardize hot flash assessment or in research studies where response burden may be an issue. The scale cutpoints and MIDs should prove useful in targeting those most in need of treatment, monitoring treatment response, and interpreting existing and future research findings.