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

Data extraction

We asked a large language model to extract each data column below from each paper.

• Study Design
  • Identify the specific type of study design used:
    • Randomized controlled trial (RCT)
    • Systematic review
    • Meta-analysis
    • Other
• Participant Characteristics
  • Diabetes type (Type 1 or Type 2)
  • Age range or mean age
  • Total number of participants
  • Gender distribution
  • Baseline HbA1c levels
  • Duration of diabetes
• Continuous Glucose Monitor (CGM) Intervention Details
  • Type of CGM used (real-time, flash, intermittently scanned)
  • Duration of CGM intervention
  • Frequency of CGM usage per week
  • Any specific instructions for CGM use
• Primary Outcomes Measured
  • List all primary outcomes, specifically focusing on:
    • HbA1c changes
    • Time in glycemic range
    • Hypoglycemia exposure
    • Long-term diabetes complications (cardiovascular disease, neuropathy, kidney disease)
• Study Limitations
  • Acknowledged study limitations
  • Sample size constraints
  • Potential biases
  • Generalizability concerns

Results

Characteristics of Included Studies

Effects of Continuous Glucose Monitoring (CGM) on Diabetes Complications

Cardiovascular Outcomes

Neurological Complications

Renal Outcomes

Relationship Between Glycemic Variability and Complications

• HbA1c Reduction: Most studies reported significant reductions in HbA1c levels with CGM use. Reported reductions ranged from 0.2% to 0.76%.
• 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: Reported that measures of glycemic variability were associated with peripheral neuropathy.

Implementation Factors

Duration of Continuous Glucose Monitoring (CGM) Use

• Short-term vs. Long-term Use: Greater improvements in glycemic control were noted with long-term CGM use.

Technology Type Impact

• Real-time CGM (rt-CGM) showed significant benefits in glycemic control, while Flash CGM (FGM) also provided improvements in glycemic outcomes.

References

1. M. Yapanis et al. (2022) Journal of Clinical Endocrinology and Metabolism
2. R. Vigersky et al. (2011) Diabetes Care
3. R. Janapala et al. (2019) Cureus
4. J. Pickup et al. (2011) British Medical Journal
5. M. Langendam et al. (2012) Cochrane Database of Systematic Reviews
6. S. Seidu et al. (2023) Diabetes Care
7. M. Lind et al. (2017) Journal of the American Medical Association (JAMA)
8. K. Eeg-Olofsson et al. (2024) Diabetes Care
9. M. Zheng et al. (2022) Diabetes Research and Clinical Practice
10. A. Karter et al. (2022) Diabetes Technology & Therapeutics