CGM vs Usual Care: Better Blood Sugar Control for Type 2 Diabetes on Insulin

clinical-trial PMID: 28828487

CGM vs Usual Care: Better Blood Sugar Control for Type 2 Diabetes on Insulin

Quick Summary: This study tested if continuous glucose monitoring (CGM) devices help people with type 2 diabetes who take multiple insulin shots each day. People using CGM saw their average blood sugar levels drop more than those sticking to standard finger-prick tests. After six months, CGM users had better overall blood sugar control without more low blood sugar episodes or changes in daily life quality.

What The Research Found

Researchers compared CGM—a small wearable device that tracks blood sugar levels all day and night—to regular blood sugar checks with finger sticks. The main goal was to see if CGM lowers HbA1c, a key blood test that shows average blood sugar over 2-3 months. (Think of HbA1c as a report card for your diabetes control—lower is better, ideally under 7% for many people.)

CGM users' HbA1c fell from 8.5% to 7.7% on average, a drop of 0.8%.
Those in usual care improved from 8.5% to 8.0%, a smaller drop of 0.5%.
The difference between groups was 0.3%, which was statistically meaningful (meaning it's unlikely due to chance).
No big differences in low blood sugar events (hypoglycemia, when blood sugar dips below 70 mg/dL) or how people felt about their lives.
Most CGM users wore the device nearly every day, averaging 6.7 days a week.

This suggests CGM can fine-tune blood sugar management for insulin users, but it doesn't fix everything like low sugar risks or daily happiness.

Study Details

Who was studied: 158 adults with type 2 diabetes for about 17 years on average. They were aged 35 to 79 (average 60 years old) and took multiple insulin shots daily. All had HbA1c levels between 7.5% and 9.9% at the start, meaning their blood sugar wasn't fully controlled.
How long: Six months (24 weeks) of monitoring, with check-ins at the end.
What they took: No pills or supplements—CGM group got Dexcom devices to wear continuously. The usual care group kept doing standard finger-prick tests and insulin adjustments as before. (Note: This study focused on tech for diabetes, not probiotics like Bacillus subtilis, which isn't mentioned here.)

The trial was randomized, meaning participants were split evenly by chance into CGM (79 people) or usual care (79 people) groups. It happened at 25 hormone specialist clinics across North America.

What This Means For You

If you have type 2 diabetes and inject insulin several times a day, CGM could help you keep blood sugar steadier without the hassle of constant finger sticks. This might mean fewer ups and downs in energy, better long-term health (like lower risk of heart issues or nerve damage), and easier talks with your doctor about insulin doses.

Real-life tip: Ask your doctor if CGM fits your routine—it's especially useful if your blood sugar swings a lot or you worry about lows at night.
Who might benefit most: Folks already on multiple daily insulins but struggling with HbA1c above 7.5%. It won't replace insulin but can make it work better.
Cost note: CGM devices aren't cheap (often $200-300/month without insurance), but many plans cover them for insulin users. Check with your provider to see if it's worth trying for tighter control.

Overall, this adds a helpful tool to your diabetes toolkit, especially since few type 2 insulin users currently use CGM.

Study Limitations

Every study has limits, and knowing them helps you decide if results apply to you.

Short time frame: Only six months, so we don't know if benefits last years or if side effects pop up later.
Funding bias: Dexcom, the company that makes the CGM devices, paid for the study, which might make results look better than they are.
Not everyone sticks to it: Participants used CGM a lot, but real life might be different if you're busy or forgetful.
No big wins elsewhere: It didn't cut low blood sugar risks or boost quality of life, so it might not feel life-changing for everyone.
Specific group: Results are for adults on multiple insulins; kids, type 1 diabetes, or pill-only users might see different outcomes.

Talk to your healthcare team to weigh these against your needs—CGM isn't a cure-all, but it's a step forward for many.

Key Findings

The study found that adults with type 2 diabetes using multiple daily insulin injections who were assigned to continuous glucose monitoring (CGM) had a statistically significant reduction in HbA1c levels compared to usual care (standard blood glucose testing) after 24 weeks. The CGM group’s HbA1c decreased from a baseline mean of 8.5% to 7.7%, while the control group’s dropped to 8.0% (adjusted mean difference: -0.3%; 95% CI: -0.5% to 0.0%; P = 0.022). However, no meaningful differences were observed in hypoglycemia rates or quality-of-life metrics.

Study Design

This was a randomized clinical trial conducted across 25 endocrinology practices in North America. The sample included 158 adults with type 2 diabetes (median duration: 17 years; age range: 35–79 years; mean age: 60 years). Participants were receiving multiple daily insulin injections and had baseline HbA1c levels between 7.5% and 9.9%. The intervention group (n = 79) used CGM, while the control group (n = 79) continued standard care. The primary outcome was HbA1c change at 24 weeks.

Dosage & Administration

No supplement or drug dosage was involved. The intervention was the use of CGM devices (provided by Dexcom, the study funder) for 24 weeks. Participants in the CGM group used the devices for an average of 6.7 days per week.

Results & Efficacy

HbA1c Reduction: CGM group improved from 8.5% to 7.7% (mean change: -0.8%), while the control group improved from 8.5% to 8.0% (mean change: -0.5%). The adjusted difference was -0.3% (95% CI: -0.5% to 0.0%; P = 0.022), indicating CGM’s superiority.
Hypoglycemia: No significant between-group differences in CGM-measured hypoglycemia (glucose <70 mg/dL).
Adherence: 79% of CGM users maintained daily or near-daily use (6.7 days/week).
Quality of Life: No notable improvements in diabetes-specific or general health-related quality-of-life measures.

Limitations

Short Duration: The 24-week follow-up period limits conclusions about long-term CGM efficacy and safety.
Funding Source: Dexcom, the CGM manufacturer, funded the study, potentially introducing bias.
Hypoglycemia Measurement: Reliance on CGM for hypoglycemia assessment may lack clinical correlation with symptoms or adverse events.
Generalizability: Participants were highly adherent to CGM, which may not reflect real-world usage.

Clinical Relevance

For adults with type 2 diabetes on multiple daily insulin injections, CGM may offer modest but statistically significant improvements in glycemic control (HbA1c reduction of 0.3% vs. usual care). However, the lack of hypoglycemia reduction and quality-of-life benefits suggests individualized consideration of CGM’s cost and usability. The study highlights a gap in current CGM adoption (few insulin-treated type 2 diabetes patients use it) and supports expanding its use in this population.

Note: This study does not involve Bacillus subtilis or any supplement; the focus is on CGM technology for diabetes management.