The following is a summary of the “Continuous glucose monitoring and metrics for clinical trials: an international consensus statement,” published in the January 2023 issue of  Diabetes and Endocrinology by Battelino, et al.

HbA1c has been the standard measure of average blood glucose levels in people with diabetes for the 3 months before the HbA1c test date in prospective clinical studies, such as randomized controlled trials, for novel medical interventions. Indicators of the degree to which HbA1c levels have changed before and after a therapeutic intervention are used by regulators in deciding whether or not to approve a drug for the treatment of diabetes. While HbA1cremains the standard of care for assessing the effects of therapeutic interventions on blood sugar levels, continuous glucose monitoring (CGM) devices are increasingly being used in prospective clinical studies to collect data and evaluate glucose profiles among study participants. 

CGM devices collect data on glycemic excursions and periods of asymptomatic hypoglycemia or hyperglycemia at intervals of 1-5 minutes (i.e., details of glycaemic control that are not provided by HbA1c concentrations alone that are measured continuously and can be analyzed in daily, weekly, or monthly timeframes). It is recommended that all clinical studies involving diabetes consider using these CGM-derived metrics, as they are the subject of standardized, internationally agreed reporting formats. To provide clinical information that investigators can consider, regulators, companies, clinicians, and people with diabetes who are stakeholders in trial outcomes, this consensus statement aims to recommend how CGM data might be used in prospective clinical studies, either as a specified study endpoint or as supportive complementary glucose metrics. 

In this consensus statement, they discuss the best practices for collecting and analyzing CGM-derived glucose data in clinical trials, including the metrics and measures to be used. The American Association of Clinical Endocrinologists, the American Diabetes Association, the Association of Diabetes Care and Education Specialists, DiabetesIndia, the European Association for the Study of Diabetes, the International Society for Pediatric and Adolescent Diabetes, the Japanese Diabetes Society, and the Juvenile Diabetes Research Foundation have all endorsed these recommendations. CGM data could provide useful information beyond HbA1c for informing therapeutic and treatment decisions, particularly in regards to hypoglycemia, postprandial hyperglycemia, and glucose variability, and a standardized approach to CGM data collection and reporting in clinical trials will encourage the use of these metrics and enhance the interpretability of CGM data