Association Between Longitudinal Time in Range and Albuminuria in Insulin-Treated Diabetes

Cross-sectional associations between continuous glucose monitoring (CGM) metrics and diabetic kidney disease (DKD) have been reported, but evidence based on longitudinal CGM metrics collected over extended periods has remained limited.

To evaluate the relationship between longitudinal CGM metrics and albuminuria in diabetes.

A single-center, retrospective, longitudinal observational study was conducted for 190 individuals with insulin-treated diabetes who had at least 3 years of CGM data. The primary exposure was time in range (TIR) across follow-up, with secondary exposures being time in tight range (TITR) and mean glycated hemoglobin (HbA1c) level. The primary outcome was the urinary albumin-to-creatinine ratio (UACR) measured closest to the end of follow-up. Multivariable linear regression and restricted cubic spline analyses were performed.

Over a median follow-up of 7.3 years, each 10-percentage-point increase in TIR was associated with an 11.8% decrease in UACR (95% confidence interval [CI], 1.5%-21.0% decrease). TITR showed a similar direction of association, but this association was not statistically significant. Each 1-percentage-point decrease in mean HbA1c level was associated with a 21.0% decrease in UACR (95% CI, 4.4%-34.6% decrease). Restricted cubic spline analysis suggested possible nonlinear associations for TIR and TITR, although these patterns were attenuated in sensitivity analyses.

Longitudinal CGM metrics, in particular TIR, were associated with albuminuria in diabetes, providing support for their clinical relevance for DKD.