ABSTRACT
Aims
To characterize changes in continuous glucose monitoring (CGM)-derived time in tight range (TIR) measures in individuals with prediabetes or non-insulintreated type 2 diabetes undergoing dietary weight loss intervention and to quantify the association between weight loss and TIR improvement.
Methods
Data from the Personal Diet Study, a 6-month behavioural weight loss intervention in adults with prediabetes or non-insulin-treated type 2 diabetes [HbA1c≤8.0% (64mmol/mol), managed with diet alone or with metformin], was analysed. Participants wore a CGM for a maximum of 2weeks at baseline and 6months. Changes in overall, daytime (06:00h–23:59h) and overnight (00:00h–05:59h) time in 54–140mg/dL or 3.0–7.8mmol/L (TIR54–140), 70–140mg/ dL or 3.9–7.8mmol/L (TIR70–140) and >140mg/dL or >7.8mmol/L (TAR>140) were analysed. The association between weight change and TIR change adjusted for demographic and clinical covariates was computed using linear regression.
Results
Baseline and 6months CGM data from 76 participants (63±8 years, 62% female, 64% White, BMI 33±5kg/m2 , HbA1c 5.8±0.6%) were analysed. Overall TIR54–140 increased (3.3% [0.3, 6.3]%; p=0.03), with improvement in daytime (3.8% [0.9, 6.8]%; p=0.01) but not overnight TIR54–140 (2.0% [−2.2, 6.1]%; p=0.36). In adjusted analysis, every 5% points of weight loss was associated with a 3.2% points increase in overall TIR54–140 (p=0.016), driven by a 3.5% points increase in daytime TIR54–140 (p=0.006). Similar associations were found for TAR>140 but not TIR70–140. There were no associations between weight loss and change in any overnight TIR measure.
Conclusion
Weight loss was associated with improved daytime TIR54–140 and TAR>140 in individuals with prediabetes and non-insulin-treated type 2 diabetes undergoing dietary intervention. The daytime time in tight range measures can complement traditional markers like HbA1c, offering a more comprehensive view of glycaemic variations during dietary weight loss programmes for individuals with prediabetes and type 2 diabetes not on insulin.