Real-Time CGM Outperforms SMBG in Glycemic Control for Type 2 Diabetes on Basal Insulin Plus Modern Therapies

Highlights

Real-time CGM significantly reduced HbA1c by 0.6% at 16 weeks and 0.5% at 32 weeks compared to SMBG in type 2 diabetes patients on basal insulin plus modern therapies. The improvement was sustained under both self-management and clinician-supported phases. Safety profiles were similar between groups, with no device-related adverse events.

Background

Type 2 diabetes affects approximately 90% of people living with diabetes worldwide. Glycated hemoglobin (HbA1c) remains a key marker for chronic glycemia and is strongly associated with long-term complications. While continuous glucose monitoring (CGM) has proven beneficial in type 1 diabetes, its role in type 2 diabetes managed with basal insulin and modern therapies like SGLT2 inhibitors or GLP-1 receptor agonists remained unclear prior to the FreeDM2 trial.

Study Design

This open-label, parallel-design, randomized controlled trial was conducted across 24 UK centers. It enrolled adults with type 2 diabetes managed with basal insulin plus modern therapies who had HbA1c levels between 7.5-11.0%. Participants were randomized 2:1 to real-time CGM (n=198) or continuation of self-monitoring of blood glucose (SMBG; n=105). The study featured two phases: weeks 1-16 focused on self-management with basal insulin self-titration, while weeks 17-32 added clinician support where additional therapies could be initiated per national guidance.

Key Findings

At baseline, both groups had similar HbA1c levels (8.8%). By week 16, the CGM group showed a significant reduction to 8.0% versus 8.7% in the SMBG group (adjusted difference -0.6%, 95% CI -0.8 to -0.3; p<0.0001). This improvement was maintained at week 32 (7.8% vs 8.3%, adjusted difference -0.5%, 95% CI -0.7 to -0.2; p<0.0001). Safety analysis revealed two instances of severe hypoglycemia in the control group but similar rates of non-device-related adverse events between groups. The study population had mean diabetes duration of 16.7 years, suggesting these benefits apply to longstanding disease.

Expert Commentary

These findings demonstrate that CGM provides clinically meaningful glycemic improvements even in patients with prolonged diabetes duration using modern therapies. The results challenge current paradigms about CGM being primarily beneficial for type 1 diabetes or insulin-dependent type 2 diabetes. The open-label design may have introduced performance bias, but the robust effect sizes suggest genuine benefits. Further research should explore cost-effectiveness and long-term outcomes.

Conclusion

The FreeDM2 trial provides strong evidence that real-time CGM outperforms SMBG for glycemic control in type 2 diabetes patients using basal insulin plus modern therapies. These findings may influence clinical guidelines regarding CGM use in this population. Future research should examine whether these glycemic improvements translate to reduced microvascular complications.

Funding and Registration

The study was funded by Abbott Diabetes Care and registered at ClinicalTrials.gov (NCT05944432).