Real-Time CGM Lowers HbA1c vs SMBG in Type 2 Diabetes
Key Takeaways
- Lower HbA1c was observed with CGM than with SMBG at both prespecified assessments.
- The open-label multicentre randomized trial enrolled adults with type 2 diabetes receiving basal insulin plus SGLT2 inhibitors, GLP-1 receptor agonists, or dual GIP/GLP-1 receptor agonists.
- Similar non-device-related adverse-event incidence was reported, and two severe hypoglycaemia events occurred in the control group.
FreeDM2 was an open-label, parallel-design, randomized controlled superiority trial across 24 UK primary and secondary care centres. Adults with type 2 diabetes were eligible if HbA1c was 7.5% to 11.0% while receiving basal insulin and contemporary glucose-lowering therapy. Participants were assigned 2:1 to CGM or continued SMBG using permuted block randomization by site, and mean baseline HbA1c was 8.8% in both groups. Of 469 screened individuals, 329 entered the baseline phase and 303 were randomized, including 198 to CGM and 105 to SMBG. The prespecified endpoints were between-group HbA1c differences at 16 and 32 weeks.
The week 16 and week 32 HbA1c results showed HbA1c of 8.0% with CGM versus 8.7% with SMBG at week 16, for an adjusted difference of -0.6 with a 95% CI from -0.8 to -0.3 and p<0.0001. At week 32, HbA1c was 7.8% with CGM and 8.3% with SMBG, for an adjusted difference of -0.5 with a 95% CI from -0.7 to -0.2 and p<0.0001. The trial included two management phases, beginning with self-management and basal insulin self-titration through week 16. Clinician-supported management followed during weeks 17 to 32, when additional therapies could be started in line with national guidance, and HbA1c remained lower with CGM at week 32.
Non-device-related adverse events occurred at a similar incidence in both groups, and two severe hypoglycaemia events occurred in the control arm. Participants and site staff were not masked to allocation, consistent with the trial's unmasked comparison design. The randomized cohort was 67% male, with a mean age of 60.7 years and a mean diabetes duration of 16.7 years. Over 32 weeks, the randomized comparison showed lower HbA1c with CGM in basal-insulin-treated adults receiving modern therapies.
Frequently Asked Questions
Where can I find CME on diabetes technology and continuous glucose monitoring?
The Endocrinology CME hub on ReachMD aggregates accredited education on diabetes technology, including continuous glucose monitoring (CGM), automated insulin delivery, and pump therapy: Endocrinology CME. Episodes routinely cover real-time CGM (rtCGM) versus self-monitoring of blood glucose (SMBG) in type 2 diabetes, CGM-based metrics (time in range, glucose management indicator), and integration of CGM with basal insulin plus SGLT2 inhibitors or GLP-1 receptor agonists — the population studied in trials like FreeDM2. CME on managing type 2 diabetes in primary care is also available at General Medicine and Primary Care CME. Both are free after a no-cost ReachMD registration.
What are the latest treatment options for type 2 diabetes?
Current treatment options for type 2 diabetes layer glucose-lowering pharmacotherapy and structured glucose monitoring on lifestyle modification. Modern regimens commonly combine basal insulin with SGLT2 inhibitors, GLP-1 receptor agonists, or dual GIP/GLP-1 receptor agonists (e.g., tirzepatide). Structured glucose monitoring with real-time CGM is an evolving option: in the FreeDM2 randomized trial of 303 adults on basal insulin plus modern glucose-lowering therapy, real-time CGM with FreeStyle Libre 3 lowered HbA1c versus continued SMBG by an adjusted -0.6 percentage points at week 16 (8.0% vs 8.7%; 95% CI -0.8 to -0.3; p<0.0001), with the advantage maintained at week 32.
Where can I find CME on managing type 2 diabetes in primary care?
The General Medicine and Primary Care CME hub on ReachMD hosts accredited education on type 2 diabetes management for primary care clinicians, including initiating and titrating basal insulin, layering SGLT2 inhibitors and GLP-1 receptor agonists, and integrating CGM into shared-decision workflows: General Medicine and Primary Care CME. Complementary specialty content is at Endocrinology CME. Trials such as FreeDM2, which enrolled 67% of participants through primary and secondary care centres in the UK, are directly relevant to the primary care setting because the first 16 weeks of the protocol relied on self-management with basal-insulin self-titration before adding clinician-supported therapy intensification.
What were the safety findings for real-time CGM versus SMBG in FreeDM2?
Non-device-related adverse events occurred at a similar incidence in both groups. Two severe hypoglycaemia events were reported in the SMBG (control) arm; none were reported in the CGM arm in the published readout. Participants and site staff were not masked to allocation, consistent with the open-label design of CGM versus fingerstick comparisons. Device-related adverse events typical of CGM systems (skin reactions, sensor adhesion issues) should be considered in clinical practice but did not alter the overall safety profile reported.
Can these FreeDM2 findings be generalized to all adults with type 2 diabetes?
No. FreeDM2 enrolled a tightly defined population: adults with type 2 diabetes, screening HbA1c 7.5%-11.0% (59-97 mmol/mol), already treated with basal-only insulin regimens plus SGLT2 inhibitors and/or GLP-1 receptor agonists, recruited across 24 UK primary and secondary care centres. The randomized cohort was 67% male, mean age 60.7 years, and mean diabetes duration 16.7 years, with mean baseline HbA1c 8.8%. Findings may not generalize to people not on basal insulin, to those on prandial insulin or intensive regimens, to populations outside the UK health system, or to patients with HbA1c outside the inclusion range.