ObjectiveTo observe and analyze the correlation between time within target glucose range (TIR) and hemoglobin A1c (HbA1c) and the risk of diabetic retinopathy (DR). MethodsA retrospective clinical study. From March 2020 to August 2021, 91 patients with type 2 diabetes mellitus (T2DM) who were hospitalized in Department of Endocrinology and Metabolic Diseases, Affiliated Hospital of Weifang Medical University, were included in the study. All patients underwent Oburg's no-dilatation ultra-wide-angle laser scan ophthalmoscopy, HbA1c and continuous glucose monitoring (CGM) examinations. According to the examination results and combined with the clinical diagnostic criteria of DR, the patients were divided into non-DR (NDR) group and DR group, with 50 and 41 cases respectively. The retrospective CGM system was used to monitor the subcutaneous interstitial fluid glucose for 7 to 14 consecutive days, and the TIR was calculated. Binary logistic regression was used to analyze the correlation between TIR, HbAlc and DR in patients with T2DM0. At the same time, a new indicator was generated, the predicted probability value (PRE_1), which was generated to represent the combined indicator of TIR and HbA1c in predicting the occurrence of DR. The receiver operating characteristic curve (ROC curve) was used to analyze the value of TIR, HbAlc and PRE_1 in predicting the occurrence of DR. ResultsThe TIR of patients in the NDR group and DR group were (81.58±15.51)% and (67.27±22.09)%, respectively, and HbA1c were (8.03±2.16)% and (9.01±2.01)%, respectively. The differences in TIR and HbA1c between the two groups of patients were statistically significant (t=3.501,－2.208; P=0.001, 0.030). The results of binary logistic regression analysis showed that TIR, HbA1c and DR were significantly correlated (odds ratio=0.960, 1.254; P=0.002, 0.036). ROC curve analysis results showed that the area under the ROC curve (AUC) of TIR, HbA1c and PRE_1 predicting the risk of DR were 0.704, 0.668, and 0.707, respectively [95% confidence interval (CI) 0.597-0.812, P=0.001; 95%CI 0.558-0.778, P=0.006; 95%CI 0.602-0.798, P=0.001]. There was no statistically significant difference between TIR, HbA1c and PRE_1 predicting the AUC of DR risk (P>0.05). The linear equation between HbAlc and TIR was HbAlc (%) = 11.37－0.04×TIR (%). ConclusionsTIR and HbA1c are both related to DR and can predict the risk of DR. The combined use of the two does not improve the predictive value of DR. There is a linear correlation between TIR and HbAlc.