Elucidating the heterogeneity of impaired awareness of hypoglycaemia in type 1 diabetes

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1 Project Summary / Abstract 2 Impaired Awareness of Hypoglycemia (IAH) in people with type 1 diabetes (T1D) is associated 3 with defects in physiological counterregulatory and symptom responses to hypoglycemia as 4 leading to increased risk of severe hypoglycemia (SH). Education and technologies such as 5 hybrid closed loop (HCL) insulin delivery reduce hypoglycemia exposure, but restoration of 6 awareness is variable. Existing tools for screening and measuring awareness, such as Clarke 7 and Gold scores lack sensitivity to detect changes in hypoglycemia awareness in the CGM 8 era of “electronic awareness”. Therefore, we need to construct and validate more advanced 9 tools that can objectively assess IAH. This project seeks to understand the factors that 10 contribute to the successful restoration of awareness of hypoglycemia using HCL in 11 those with T1D and IAH and validate the tools required to assess changes in awareness 12 status. To address the specific questions in the call, we propose 5 sub-studies. 13 1. Study 1: To understand the physiological responses to experimental hypoglycemia in T1D 14 with NAH and the impact of a switch to hybrid closed loop on these responses over time. 15 2. Study 2: To determine if reducing exposure to biochemical hypoglycemia by switching to 16 state of the art hybrid closed loop technology can restore physiological responses to 17 experimental hypoglycemia over time in individuals with T1D and IAH 18 3. Study 3: To determine if hypoglycaemia specific education (HARPdoc) that addresses 19 cognitions and beliefs associated with IAH that are possible barriers to hypoglycemia 20 avoidance (even with technology) leads to further reductions in hypoglycemia exposure 21 and improved physiological responses to hypoglycemia in individuals with T1D and IAH 22 4. Study 4: To determine the factors associated with restoration of physiological responses 23 to hypoglycemia. We will categorise participants into Restored (R-IAH), Partial ( P-IAH) or 24 Sustained (S-IAH) impaired awareness of hypoglycemia based on changes in physiological 25 (epinephrine and symptom) responses to experimental hypoglycemia in clamp studies and 26 investigate demographic, glycemic and behavioural factors associated with each category. 27 5. Study 5: To determine diagnostic cut-offs for Normal, P-IAH and S-IAH responses to 28 experimental hypoglycemia for current self-report questionnaires and a novel tool named 29 the HypoMETRICS app. We will also use the HypoMETRICS app to explore differences 30 between “physiological” and “technological” awareness of hypoglycemia.