Blood glucose symptom beliefs of diabetic patients: accuracy and implications

Both diabetic patients and health care practitioners often assume that the subjective symptoms of extreme low and high blood glucose (BG) levels are easily recognized. This study tested the accuracy of BG symptom beliefs in a group of 26 insulin-dependent diabetic patients. A within-subject, repeated measures design was used to identify symptoms related to low and high glucose levels for individual subjects. On three occasions over a 1-year period, subjects completed symptom checklists just prior to 40 consecutive self-measurements of BG (an average of four times per day for 10 days). At the end of the year, subjects reported which symptoms they believed were related to their own low and high glucose levels. After determining whether each checklist item was empirically related to glucose levels and believed to relate to glucose levels, symptom beliefs were categorized as hits, false alarms, misses, or correct rejections. Across subjects, the frequency of accurate beliefs (hits and correct rejections) was higher than the frequency of inaccurate beliefs (false alarms and misses). Symptom belief accuracy differed greatly for individual subjects, however, and every subject had at least one inaccurate belief. False alarm beliefs were the more common type of error. Female subjects' symptom beliefs yielded more hits, as well as more false alarms. Males missed more symptoms, especially low BG symptoms, than females. Symptom belief accuracy was greater if symptom-glucose relationships remained stable across time.