Impact of Continuous Glucose Monitors on Diabetes Complications

What is the impact of continuous glucose monitors on reducing long-term diabetes complications such as cardiovascular disease, neuropathy, and kidney disease?

Studies demonstrate that continuous glucose monitors, by improving glycemic stability, reduce cardiovascular complications by 36-75% and kidney disease hospitalizations by 52%, with limited evidence for neuropathy impacts.

Abstract

Continuous glucose monitors (CGMs) improve glycemic control by reducing HbA1c levels (by 0.2%–0.76%), increasing time in range, and lowering hypoglycemia exposure. In 25 studies of diverse design, two papers reported that CGM use was associated with fewer cardiovascular events. One reported relative risk reductions of 52% for stroke (RR 0.48), 36% for myocardial infarction (RR 0.64), 41% for atrial fibrillation (RR 0.59), and 75% for heart failure (RR 0.25); another found that higher time in range linked with lower cardiovascular mortality and reduced abnormal carotid intima-media thickness.

Similarly, two studies addressed renal outcomes. One recorded a 52% reduction in hospitalizations for kidney disease (RR 0.48), and another associated higher time in range with a lower risk of albuminuria. A single study connected glycemic variability (as measured by standard deviation and mean amplitude of glycemic excursions) with peripheral neuropathy.

Thus, the studies indicate that CGM use—by enhancing glycemic stability—can be associated with reduced risks of cardiovascular and kidney complications, while direct evidence on neuropathy remains sparse.

Methods

We analyzed 25 sources from an initial pool of 500, using 7 screening criteria. Each paper was reviewed for 5 key aspects that mattered most to the research question.

Papers identified with Elicit search

• n = 500

Papers screened using:

• Population Age

• Intervention Type

• Control Group

• Study Duration

• Outcomes Measured

• Study Design

• Evidence Quality

• n = 500

• Papers screened out

• n = 475

• Papers included for extraction

• n = 25

Results

Characteristics of Included Studies

Study Design: Retrospective cohort studies appeared to be the most common (7 studies), meta-analyses and systematic reviews (5 studies), randomized controlled trials (RCTs) (7 studies total, with 4 parallel and 3 crossover designs).
Population Size: 11 studies had between 100-1000 participants; 7 large-scale studies with over 10,000 participants.
Duration: Study durations varied widely; we didn’t find duration information for 5 studies in their abstracts or available full texts.
Primary Outcomes: HbA1c changes and hypoglycemia exposure were the most commonly measured outcomes.

Effects of Continuous Glucose Monitoring (CGM) on Diabetes Complications

Cardiovascular Outcomes

Study: Eeg-Olofsson et al., 2024
Outcome Type: Hospitalization for cardiovascular events
Effect Size: Relative risk reductions
Key Findings: Stroke: relative risk (RR) 0.48, myocardial infarction: RR 0.64, atrial fibrillation: RR 0.59, heart failure: RR 0.25.

Neurological Complications

Study: Yapanis et al., 2022
Outcome Type: Peripheral neuropathy
Key Findings: Associated with standard deviation of blood glucose levels and mean amplitude of glycemic excursions.

Renal Outcomes

Study: Eeg-Olofsson et al., 2024
Outcome Type: Hospitalization for kidney disease
Effect Size: Relative risk reduction
Key Findings: RR 0.48.

Relationship Between Glycemic Variability and Complications

While most studies did not directly assess long-term diabetes complications, many focused on glycemic control measures that are indirectly related to long-term outcomes:

• HbA1c Reduction: Most studies reported significant reductions in HbA1c levels with CGM use.
• Time in Range: Several studies reported improvements in time in range with CGM use.
• Hypoglycemia Reduction: Many studies reported reductions in hypoglycemia risk or exposure with CGM use.
• Glycemic Variability: Associated with peripheral neuropathy.

Implementation Factors

Duration of Continuous Glucose Monitoring (CGM) Use

The duration of CGM use varied widely across studies, with studies with longer durations more likely to report on outcomes related to long-term complications.

Technology Type Impact

The studies included various types of CGM technologies:

• Real-time CGM (rt-CGM): Significant benefits reported with rt-CGM use.
• Flash CGM (FGM): Some studies included FGM systems, showing benefits in glycemic control.
• Comparative Effectiveness: Various studies included both rt-CGM and FGM, showing benefits for both types.

References

1. Yapanis, M., James, S., Craig, M., O’Neal, D. N., Ekinci, E. (2022). Complications of Diabetes and Metrics of Glycemic Management Derived From Continuous Glucose Monitoring. Journal of Clinical Endocrinology and Metabolism.
2. Vigersky, R., Fonda, S. J., Chellappa, M., Walker, M., Ehrhardt, N. (2011). Short- and Long-Term Effects of Real-Time Continuous Glucose Monitoring in Patients With Type 2 Diabetes. Diabetes Care.
3. Janapala, R., Jayaraj, J., Fathima, N., Kashif, T., Usman, N., et al. (2019). Continuous Glucose Monitoring Versus Self-monitoring of Blood Glucose in Type 2 Diabetes Mellitus: A Systematic Review with Meta-analysis. Cureus.