Glycemia risk index (GRI): a metric designed to facilitate the interpretation of continuous glucose monitoring data: a narrative review.

The Glycemia Risk Index (GRI) is a novel composite metric that integrates both hypoglycemia and hyperglycemia episodes to provide a comprehensive view of glycemic control in individuals with type 1 or type 2 diabetes. Unlike traditional metrics such as HbA₁c or time-in-range (TIR), the GRI highlights extreme glycemic excursions and aligns more closely with clinical perceptions of glycemic risk. It correlates well with other CGM-derived indicators and has demonstrated relevance in various settings, including the management of individuals using hybrid closed-loop systems. In individuals with HbA₁c ≤ 7%, the GRI can reveal hidden risks not captured by HbA₁c alone, highlighting its added value in routine clinical assessment. Despite these strengths, the GRI has limitations. It was developed using CGM data from healthy adults on intensive insulin therapy, limiting generalization to other populations. Unlike HbA₁c or TIR, it is not yet validated against hard clinical outcomes. As CGM technology evolves, the GRI holds promise as a valuable tool, provided its current limitations are addressed through further research and clinical integration.