Hot flash clinical trial baseline measurements: how long is needed?

Abstract

ObjectivesClassically, hot flash studies included a baseline period of 1 week or longer. The objective of this study was to compare the accuracy of a 1-day baseline diary to a traditional 1-week diary.MethodsRaw data from 5 pilot studies and 15 phase III randomised controlled trials (RCTs), all of which used a 1-week baseline period, were obtained. Descriptive statistics were used to describe day-by-day variations in hot flash frequencies and scores, during the baseline week. Additional analyses evaluated whether the conclusions from any of the individual pilot studies would have been changed if only a 1-day baseline period had been used. For the RCTs, p values were recalculated using mixed models, adjusting for the baseline value by including it as a covariate.ResultsA total of 2573 participants were included. On average, participants had 8.5 hot flashes per day on day 1. Mean hot flash frequencies and scores on subsequent days (days 2–7) were within 6% of day 1 values. When comparing a 1-day to a 1-week baseline period, there was an absolute difference of only 0.29 hot flashes per day (SD 2.25). Reanalysis for each pilot study revealed that no individual study conclusions would have been altered by a shorter baseline. For the RCTs, a shorter baseline period changed the results of only 1 of 24 comparisons from statistically significant to not significant, or vice versa.ConclusionsA 1-day hot flash diary appears to accurately reflect the true frequency and severity of baseline symptoms in appropriately sized cohorts.

The complexity of genitourinary syndrome of menopause: number, severity, and frequency of vulvovaginal discomfort symptoms in women enrolled in a randomized trial evaluating treatment for genitourinary syndrome of menopause

“…13 However, in people enrolled in clinical trials, the day-to-day variability in number of hot flashes is only 6%. 14 This suggests that the people in our clinical trial may have more frequent and consistent vulvovaginal symptoms than the general population; however, there are no data on frequency of symptoms for comparison. We did not collect data on frequency of sexual intercourse in the month before enrollment, and so interpretation of the frequency of the pain with penetration symptom is difficult.…”

“…Among people with hot flashes, only a quarter have daily hot flashes 13 . However, in people enrolled in clinical trials, the day-to-day variability in number of hot flashes is only 6% 14 . This suggests that the people in our clinical trial may have more frequent and consistent vulvovaginal symptoms than the general population; however, there are no data on frequency of symptoms for comparison.…”