South Korean Research Shows CGM Works Best When Paired With Structured Education

A study from South Korea suggests that continuous glucose monitoring (CGM) is only part of the equation—how patients are taught to use CGM data may matter just as much as wearing the device itself. Researchers at Samsung Medical Center in Seoul found that type 2 diabetes patients on insulin who received structured education on reading CGM graphs reduced their A1C nearly twice as much as those using CGM or traditional finger-stick testing without that specialized guidance.

What the Researchers Did

This 24-week randomized controlled trial enrolled 159 adults with type 2 diabetes who were already on multiple daily insulin injections (MDI)—meaning they were injecting insulin several times per day. Participants had starting A1C levels between 7.5% and 12.0%, indicating moderate to poor blood sugar control. They were divided into three equal groups:

• Group 1 (Intervention): Intermittently scanned CGM (isCGM) + structured education on reading glucose trend graphs to adjust insulin dose and timing
• Group 2 (Control): isCGM + standard diabetes education only
• Group 3 (Control): Traditional finger-stick blood glucose monitoring (BGM) + standard education

Key Findings — Converted to US Units

At the start of the study, the average blood sugar (A1C) across all participants was approximately 8.4%, equivalent to an estimated average glucose of about 194 mg/dL.

After 24 weeks, A1C reductions were:

• CGM + Structured Education: −1.00% reduction (most effective)
• CGM + Standard Education: −0.63% reduction
• Finger-Stick + Standard Education: −0.58% reduction

The structured education group's improvement was statistically significant compared to both control groups (p=0.037 vs. CGM-only; p=0.019 vs. finger-sticks). Notably, adverse event rates were also lower in the CGM groups (about 27–29%) compared to the finger-stick group (48%).

Why This Matters for US Patients

In the United States, CGM adoption among type 2 diabetes patients on insulin has grown rapidly, especially since Medicare expanded CGM coverage in recent years. The American Diabetes Association (ADA) recommends CGM for adults with type 2 diabetes using insulin, with an A1C target of below 7.0% for most adults.

However, many American patients receive a CGM device with little guidance on how to interpret the trend arrows, graphs, and patterns it produces. This South Korean trial reinforces what many US diabetes educators suspect: the device alone isn't enough. Structured, pattern-based education—teaching patients to look at glucose curves and adjust insulin timing accordingly—appears to be the critical ingredient that unlocks CGM's full potential.

This international perspective is particularly valuable because South Korea's healthcare system encourages intensive outpatient diabetes management, offering a model for how structured CGM education programs could be integrated into US clinical practice, particularly for patients already on complex insulin regimens.

If you use a CGM and haven't received formal training on reading your glucose trend graphs, ask your care team about diabetes education programs that specifically address CGM pattern interpretation.

Study Citation

Kim, Jin, Sim et al. "Continuous glucose monitoring with structured education in adults with type 2 diabetes managed by multiple daily insulin injections: a multicentre randomised controlled trial." Diabetologia (2024). DOI: 10.1007/s00125-024-06152-1. PMID: 38639876.