Identifying the Relationship Between CGM Time in Range and Basal Insulin Adherence in People With Type 2 Diabetes

BACKGROUND: The study aimed to determine the relationship between basal insulin adherence and glycemic control evaluated by time in range (TIR) in people with insulin-treated type 2 diabetes (T2D), using data from both continuous glucose monitors (CGM) and connected insulin pens. Furthermore, the study aimed to determine the best basal insulin adherence metric.

METHODS: CGM data and basal insulin data were collected from 106 insulin-treated people (aged ≥18 years) with T2D. Three different adherence metrics were employed (dose deviation, dose deviation ≤20%, and a traditional metric) and a three-step methodology was used to measure insulin adherence level. The coefficient of determination (R2), based on a univariate linear regression analysis, was used to determine the relationship between each adherence metric and TIR.

RESULTS: A statistically significant relationship was observed between TIR and adherence quantified as the dose deviation ≤20% metric (R2 = 0.67, P = .006). Neither the relationship between the dose deviation metric and TIR (R2 = 0.43, P = .08) nor the relationship between the traditional metric and TIR (R2 = 0.35, P =.23) was found to be statistically significant.

CONCLUSIONS: Our study indicates a relationship between basal insulin adherence and TIR in people with insulin-treated T2D. This seems to underscore the role of basal insulin adherence for optimal glycemic outcomes and utilizing TIR as a clinical marker. Furthermore, the results suggest that the magnitude of deviation from the recommended basal insulin dose impacts glycemic control, indicating dose deviation ≤20% as a more accurate metric for quantifying adherence.