Does Continuous Glucose Monitoring (CGM) Restore Hypoglycemia Awareness in Patients with Type 1 Diabetes (T1D) Who Previously Had Impaired Awareness of Hypoglycemia (IAH)?

IAH occurs in up to 1/3 of adults with T1D and it increases the risk of severe hypoglycemia (SH).Studies demonstrate that using CGM reduces the time spent in hypoglycemia (HG), but the effect of CGM on reversing IAH is not clear. We have enrolled many study subjects with T1D and IAH over the years and recently contacted them to determine how many continue to have IAH, how many have used CGM, and if there is a correlation between CGM use and restoration of HG awareness.

Thirty six with T1D and IAH according to the Clarke/Cox questionnaire (CC) administered 2009-2015 were contacted to complete an online survey that included the CC, the Gold questionnaire, and questions about their diabetes. 12 M, 11 F responded. One had an islet cell transplant and was excluded. Median duration was 36 ± 12 years, mean age was 50 ± 12 years and the median HgB A1C was 6.8 ± 1%.

Persistent IAH defined by both questionnaires was typical. Nineteen of 22 classified as IAH on the current survey reported severe HG over the last 6 mo. While there was a trend that showed consistent use of CGM was higher among people with no episodes of severe HG over the last 6 months this was not statistically significant.

These observations show that persistent IAH is common in T1D. While the consistent use of CGM among our participants was high it did not translate into restoration of HG awareness in this population.