Understanding the clinical implications of differences between glucose management indicator and glycated haemoglobin

Laboratory measured glycated haemoglobin (HbA1c) is the gold standard for assessing glycaemic control in people with diabetes and correlates with their risk of long-term complications. The emergence of continuous glucose monitoring (CGM) has highlighted limitations of HbA1c testing. HbA1c can only be reviewed infrequently and can mask the risk of hypoglycaemia or extreme glucose fluctuations. While CGM provides insights in to the risk of hypoglycaemia as well as daily fluctuations of glucose, it can also be used to calculate an estimated HbA1c that has been used as a substitute for laboratory HbA1c. However, it is evident that estimated HbA1c and HbA1c values can differ widely. The glucose management indicator (GMI), calculated exclusively from CGM data, has been proposed. It uses the same scale (% or mmol/mol) as HbA1c, but is based on short-term average glucose values, rather than long-term glucose exposure. HbA1c and GMI values differ in up to 81% of individuals by more than ±0.1% and by more than ±0.3% in 51% of cases. Here, we review the factors that define these differences, such as the time period being assessed, the variation in glycation rates and factors such as anaemia and haemoglobinopathies. Recognizing and understanding the factors that cause differences between HbA1c and GMI is an important clinical skill. In circumstances when HbA1c is elevated above GMI, further attempts at intensification of therapy based solely on the HbA1c value may increase the risk of hypoglycaemia. The observed difference between GMI and HbA1c also informs the important question about the predictive ability of GMI regarding long-term complications

Efficacy of a connected insulin pen cap in people with non-controlled type 1 diabetes mellitus: a multicenter randomized clinical trial

   Objective: To assess the efficacy of the insulin pen cap Insulclock® on improving glycemic control, treatment adherence, and users’ satisfaction in people with type 1 diabetes.  Research Design and Methods: This multicenter, open-label, randomized, controlled trial comprised a 4-week run-in phase and a 6-week double-arm phase, in which participants were randomized to use Insulclock® into an active or masked mode.  Results: Fifty-five participants were evaluable (active group: 26, masked group: 29). The increase in TIR was higher in the active vs. the masked group (+5.2% vs. -0.8%; p=0.016). The active group showed a higher reduction in mean glucose, glucose management indicator (GMI), time above range (TAR), and high blood glucose index (HBGI). On-time insulin doses increased in the active group and decreased in the masked group. Conclusions: Insulclock® system use was associated with improved glycemic control, glycemic variability, hyperglycemia risk, and treatment adherence in people with uncontrolled type 1 diabetes.</p