Comparison of Glycemia Risk Index with Time in Range for Assessing Glycemic Quality
Ji Yoon Kim, Ji Yoon Kim, Jee Hee Yoo, Jae Hyeon Kim, Jae Hyeon Kim, Jae Hyeon Kim
Abstract
Background: The glycemia risk index (GRI) is a novel composite continuous glucose monitoring (CGM) metric that gives greater weight to hypoglycemia than to hyperglycemia and to extreme hypo/hyperglycemia over less extreme hypo/hyperglycemia. This study aimed at validating the effectiveness of GRI and at comparing it with time in range (TIR) in assessing glycemic quality in clinical practice. Methods: A total of 524 ninety-day CGM tracings of 194 insulin-treated adults with diabetes were included in the analysis. GRI was assessed according to standard metrics in ambulatory glucose profiles. Both cross-sectional and longitudinal analyses were performed to compare the GRI and TIR. Results: The GRI was strongly correlated not only with TIR ( r = −0.974), but also with the coefficient of variation ( r = 0.683). To identify whether the GRI differed by hypoglycemia even with a similar TIR, CGM tracings were grouped according to TIR (50% to <60%, 60% to <70%, 70% to <80%, and ≥80%). In each TIR group, the GRI increased as time below range (TBR) <70 mg/dL increased ( P < 0.001 for all TIR groups). In longitudinal analysis, as TBR <70 mg/dL improved, the GRI improved significantly ( P = 0.003) whereas TIR did not ( P = 0.704). Both GRI and TIR improved as time above range (TAR) >180 mg/dL improved ( P < 0.001 for both). The longitudinal change was easily identifiable on a GRI grid. Conclusions: The GRI is a useful tool for assessing glycemic quality in clinical practice and reflects hypoglycemia better than does TIR.