Association of continuous glucose monitoring metrics with cardiovascular and kidney outcomes in type 2 diabetes: Data from the GRADE-CGM substudy.

AIMS: We compared associations of CGM-derived time in range (TIR) and glucose management indicator (GMI) vs. HbA1c with CVD and eGFR decline in type 2 diabetes.

METHODS

We studied 1363 participants with ≥10-day blinded CGM in the GRADE-CGM Substudy. Exposures were TIR and GMI, with HbA1c as comparator. Cox models estimated hazard ratios (HR) for the composite of any CVD or all-cause death. Linear mixed-effects models estimated eGFR slope. Models were adjusted for age, sex, race/ethnicity, treatment group, diabetes duration, and baseline eGFR, then mutually adjusted each CGM metric with HbA1c.

RESULTS

Over median 2.3 years, 74 CVD or death occurred, eGFR slope was -2.37 mL/min/1.73m2/year. GMI, HbA1c, and TIR were each significantly associated with CVD/death (adjusted HR 1.44 [1.21-1.71] per 1% GMI; 1.37 [1.16-1.61] per 1% HbA1c; 0.73 [0.61-0.87] per 20% TIR). Higher GMI and HbA1c were associated with faster eGFR decline (-0.35 [-0.63, -0.07] and - 0.38 [-0.65, -0.11] mL/min/1.73m2/year); TIR was not significantly associated with eGFR slope. After mutual adjustment, most associations of CGM metrics and HbA1c with outcomes were attenuated.

CONCLUSIONS

In type 2 diabetes, GMI and HbA1c were comparably associated with cardiovascular and kidney outcomes, whereas TIR was associated with cardiovascular outcomes only.