Associations of time in tight range, time in range, and glycated hemoglobin with albuminuria in type 1 diabetes: A cross-sectional study

Aims: We aimed to establish an independent association between time in tight range (TITR) and the risk of albuminuria, and to compare the relationships of TITR, time in range (TIR), and glycated hemoglobin (HbA1c) with albuminuria in individuals with type 1 diabetes (T1D). Methods: This cross-sectional study analyzed 14-day raw continuous glucose monitoring (CGM) data from 615 individuals with T1D. Albuminuria was defined as a spot urine albumin-to-creatinine ratio ≥ 30 mg/g. Multivariable logistic regression models were used to estimate the odds ratios (OR) for albuminuria per 10 % increase in TITR and TIR. Results: The adjusted OR for albuminuria per 10 % increase in TITR was 0.98 (95 % confidence interval [CI], 0.96–0.99; p = 0.002). A comparable association was observed with TIR (adjusted OR, 0.97; 95 % CI, 0.96–0.99; p < 0.001). Restricted cubic spline analysis showed that albuminuria risk decreased with increasing TITR and TIR, plateaued near HbA1c 7 %, but further decreased at very high TITR and TIR levels, unlike HbA1c, which had a single threshold. Conclusion: TITR is independently associated with the risk of albuminuria in T1D, exhibiting a similar pattern to TIR but a different pattern from HbA1c. Very high TITR and TIR may provide information predicting albuminuria risk beyond HbA1c levels.