How CGM Use in Adults With Type 2 Diabetes Leads to Glycemic Benefits: The Role of Medication and Behaviour Change

Abstract

Introduction: Although continuous glucose monitoring (CGM) in adults with type 2 diabetes (T2D) has known glycemic benefits, the underlying behavioural and psychosocial processes driving these outcomes remain poorly understood. We examined how CGM influences patient-reported outcomes and whether changes in those outcomes predict glycemic improvement. Research Design and Methods: This 6-month prospective observational study included 115 adults with T2D and elevated HbA1c who did not use fast-acting insulin and initiated CGM through a real-world program. At baseline, 3- and 6-months, HbA1c, medication use/changes and key psychosocial and self-care behaviours were assessed. Longitudinal structural equation models assessed changes over time and predictors of HbA1c reduction. Post hoc moderation analyses explored whether the effect of self-care behaviour improvements on HbA1c outcomes depended upon new medication starts at baseline. Results: HbA1c declined significantly from 9.4% (79 mmol/mol) at baseline to 7.3% (56 mmol/mol) at both 3 and 6 months (ps < 0.001). Participants reported increased diabetes engagement, reduced distress, increased physical activity, fewer missed medications and less overeating (ps < 0.001). In multivariate models, greater HbA1c reduction was independently predicted by: (1) starting a new diabetes medication in the few months before baseline (b = −1.06, p < 0.001); (2) increases in physical activity (b = −0.13, p = 0.040); and (3) improvements in medication-taking (b = 2.33, p < 0.001). Post hoc moderation analysis revealed that behaviour changes were most predictive of glycemic benefit among participants who had not started a new diabetes medication pre-baseline. Conclusions: Real-world CGM initiation was associated with significant improvements in glycemic control, self-care behaviours and psychosocial outcomes. Behaviour change—notably, improved diet and physical activity—was a key contributor to glycemic gains, particularly among those not undergoing medication adjustments prior to CGM initiation. These findings support CGM as a catalyst for engagement and behaviour change in T2D management.