Various methods can be used to evaluate awareness of hypoglycemia in people with type 1 diabetes, but their comparative accuracy in identifying this clinical syndrome has not been examined. Participants completed a questionnaire to assessing their hypoglycemia awareness status using each of the three methods available for this purpose (designated as the Gold, Clarke and Pedersen-Bjergaard methods). Blood glucose measurements were then recorded four times daily, prospectively over a four-week period. Data were obtained from 80 patients (55 male; HbA1c 8.1% {1.4}; age, median (IQR) 47.5 (35.5-56.3), years old; duration of diabetes, median (IQR) 20 years {9-31}). Utilising the three methods, the prevalence of impaired awareness of hypoglycemia (IAH) were 24% (Gold), 26% (Clarke) and 62.5% (Pedersen-Bjergaard) respectively. Patients who were identified as having IAH with the Gold method were significantly older (p = 0.01), had a longer duration of diabetes (p = 0.04), recorded more biochemical hypoglycemia over the 4-week monitoring period (p = 0.003), experienced lower autonomic symptom scores during hypoglycemia (p = 0.005) and reported a higher incidence of severe hypoglycemia (SH) during the preceding year (p = 0.001), compared to those with normal awareness. Very similar findings were obtained with the Clarker method. By contrast, the Pedersen-Bjergaard method identified only a long duration of diabetes and a history of SH as factors associated with IAH. In evaluating awareness of hypoglycemia it is suggested that the methods of Clarke or Gold should be utilised preferentially to identify people with this acquired syndrome. [ABSTRACT FROM AUTHOR]