Comparison of glucose time in range and area under curve in range in relation to risk of diabetic retinopathy in type 2 diabetes patients

AIMS/INTRODUCTION: We proposed a novel continuous glucose monitoring (CGM)‐based metric, area under the curve in range (AucIR), for integrating both the amplitude and duration of dysglycemia, and further compared AucIR with the emerging key CGM‐derived metric, time in range (TIR). MATERIALS AND METHODS: A total of 2,030 adult patients with type 2 diabetes were enrolled during May 2020 to October 2021. AucIR and TIR were measured with 7‐day CGM data. Logistic regression analysis and the C‐statistic was carried out to assess the association of AucIR and TIR with diabetic retinopathy (DR). RESULTS: Both AucIR (r = −0.89) and TIR (r = −0.95) were strongly correlated with mean glucose levels. Compared with TIR, AucIR showed a tighter relationship with parameters of glycemic variability, including the coefficient of variation (r = −0.56), standard deviation (r = −0.89) and mean amplitude of glycemic excursions (r = −0.70). For each absolute 10% decrease in AucIR, the risk of DR was increased by 7% (95% confidence interval 1.02–1.13) after adjustment for confounders. With respect to TIR, each absolute 10% decrease was associated with an 8% (95% confidence interval 1.03–1.14) increased risk of DR. The model discrimination for DR, as measured by C‐statistic, did not differ significantly between the two metrics (P > 0.05). CONCLUSIONS: AucIR did not provide added benefit over TIR in the assessment of DR risk among patients with type 2 diabetes. The potential value of AucIR needs to be explored in future studies.