Accuracy of Subjective Hot Flush Reports Compared With Continuous Sternal Skin Conductance Monitoring

Abstract

To compare 2 subjective and 1 objective method for assessing hot flush frequency: prospective paper hot flush diaries, prospective electronic event markers, and the Biolog ambulatory sternal skin conductance monitor. Fifty-five breast cancer survivors provided two 24-hour periods of data, 1 week apart, at baseline before being randomized for an intervention study. Women completed a prospective paper hot flush diary and pressed an event marker to subjectively record each hot flush they experienced while wearing a sternal skin conductance monitor. Sensitivity was uniformly low (< 50%) for both subjective methods at each week. The estimated probability that a woman would record a true monitor-verified hot flush subjectively by diary or event marker was between 36% and 50% of the time if she was awake and between 22% and 42% of the time if she was asleep. Underreporting of diary hot flushes consequently resulted in more than 50% missing severity and bother ratings. Specificity was high (96-98%) for both the diary and event marker, for both weeks, and for both waking and sleeping times. The positive predictive value was low (34-52%), and negative predictive value was high (94-97%). This indicates that, rather than overreporting hot flushes when they did not exist, women tended to underreport hot flushes when they did exist. Use of prospective paper hot flush diaries and electronic event markers may seriously underestimate hot flush frequency and result in missed intensity and bother ratings.