Elicit: Impact of Continuous Glucose Monitors on Diabetes Complications
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 out: n = 475
- Papers included for extraction: n = 25
Screening
We screened in sources based on their abstracts that met these criteria:
- Population Age: Does the study focus exclusively on adult participants (≥18 years) with type 1 or type 2 diabetes?
- Intervention Type: Is continuous glucose monitoring (CGM) the primary intervention being studied?
- Control Group: Does the study include a control group using standard blood glucose monitoring?
- Study Duration: Is the study duration at least 12 months?
- Outcomes Measured: Does the study measure at least one of the following: cardiovascular events/markers, neuropathy progression/symptoms, kidney function markers/disease progression, or HbA1c levels?
- Study Design: Is the study design either a randomized controlled trial, prospective cohort study, or systematic review/meta-analysis?
- Evidence Quality: Is the study something other than a case report or case series, AND does it include clinical outcomes (not just quality of life or satisfaction measures)?
Data Extraction
We extracted data from each study following the guidelines on various columns:
- Study Design: Specify the type of study.
- Participant Characteristics: Extract details on diabetes type, age range, total participants, gender distribution, baseline HbA1c levels, and duration of diabetes.
- Continuous Glucose Monitor (CGM) Intervention Details: Specify the type of CGM, duration of intervention, frequency of usage, and specific instructions.
- Primary Outcomes Measured: List outcomes focusing on HbA1c changes, time in glycemic range, hypoglycemia exposure, and long-term diabetes complications.
- Study Limitations: Extract acknowledged limitations and potential biases.
Results
Characteristics of Included Studies
| Study | Study Design | Population Size | Duration | Primary Outcomes Measured | Full text retrieved |
|---|---|---|---|---|---|
| Anderson et al., 2011 | Retrospective cohort study | 77 | Long-term (≥3 months), Short-term (<3 months) | HbA1c changes, Hypoglycemia exposure | Yes |
| Cho et al., 2023 | Prospective observational cohort study with propensity score matching | 539 | 1 year | HbA1c changes, Time in glycemic range, Hypoglycemia exposure | Yes |
| Dinneen et al., 2009 | Randomized Controlled Trial (RCT) - Parallel group | 404 | 18 months | HbA1c changes | No |
| Eeg-Olofsson et al., 2024 | Retrospective cohort study | 11,822 | No mention found | HbA1c changes, Hypoglycemia exposure, Long-term complications (cardiovascular, kidney disease) | No |
| Idris, 2023 | Observational retrospective study | 20,721 | 12 months | HbA1c changes, Hypoglycemia exposure, Hyperglycemia exposure, All-cause hospitalization | No |
| Janapala et al., 2019 | Retrospective study | 51 | Part of a three-year retrospective study | HbA1c changes, Time in glycemic range, Hypoglycemia exposure | Yes |
| Karter et al., 2021 | Exploratory retrospective cohort study | 41,753 | No mention found | HbA1c changes, Hypoglycemia exposure, Hyperglycemia exposure, Healthcare utilization | No |
| Karter et al., 2022 | Retrospective cohort study using a difference-in-differences approach | 17,422 | 2015-2019 | HbA1c changes, Hypoglycemia exposure | Yes |
| Langendam et al., 2012 | Randomized Controlled Trial (RCT) - Crossover | 153 | 6 months | HbA1c changes, Time in glycemic range, Hypoglycemia exposure | Yes |
| Lind et al., 2017 | Randomized Controlled Trial (RCT) - Crossover | 161 | 26 weeks | HbA1c changes, Hypoglycemia exposure | No |
- Study designs varied, with a mix of retrospective and randomized controlled studies.
Effects of Continuous Glucose Monitoring (CGM) on Diabetes Complications
Cardiovascular Outcomes
| Study | Outcome Type | Effect Size | Follow-up Duration | Key Findings |
|---|---|---|---|---|
| Eeg-Olofsson et al., 2024 | Hospitalization for cardiovascular events | Relative risk reductions | No mention found | Stroke: RR 0.48, Acute myocardial infarction: RR 0.64, Atrial fibrillation: RR 0.59, Heart failure: RR 0.25 |
| Yapanis et al., 2022 | Cardiovascular disease mortality | No mention found | No mention found | Higher time in range associated with reduced risk |
Neurological Complications
| Study | Outcome Type | Effect Size | Follow-up Duration | Key Findings |
|---|---|---|---|---|
| Yapanis et al., 2022 | Peripheral neuropathy | No mention found | No mention found | Associated with SD of blood glucose levels |
Renal Outcomes
| Study | Outcome Type | Effect Size | Follow-up Duration | Key Findings |
|---|---|---|---|---|
| Eeg-Olofsson et al., 2024 | Hospitalization for kidney disease | Relative risk reduction | No mention found | RR 0.48 |
| Yapanis et al., 2022 | Albuminuria | No mention found | No mention found | Higher time in range associated with reduced risk |
Relationship Between Glycemic Variability and Complications
- Most studies reported significant reductions in HbA1c levels with CGM use, with reductions ranging from 0.2% to 0.76%.
- Several studies indicated improvements in time in range with CGM use, linking higher time in range to reduced risks of complications.
Implementation Factors
Duration of Continuous Glucose Monitoring (CGM) Use
- The duration of CGM use varied across studies, with some demonstrating sustained benefits of long-term CGM use.
Technology Type Impact
- Various types of CGMs were included, with both real-time and intermittently scanned systems demonstrating benefits in glycemic control.
References
- M. Yapanis et al. (2022). Complications of Diabetes and Metrics of Glycemic Management Derived From Continuous Glucose Monitoring. Journal of Clinical Endocrinology and Metabolism.
- R. Vigersky et al. (2011). Short- and Long-Term Effects of Real-Time Continuous Glucose Monitoring in Patients With Type 2 Diabetes. Diabetes Care.
- R. Janapala et al. (2019). Continuous Glucose Monitoring Versus Self-monitoring of Blood Glucose in Type 2 Diabetes Mellitus: A Systematic Review with Meta-analysis. Cureus.
- K. Eeg-Olofsson et al. (2024). Initiation of Intermittently Scanned Continuous Glucose Monitoring Is Associated With Reduced Hospitalization for Acute Diabetes Events and Cardiovascular Complications in Adults With Type 1 Diabetes. Diabetes Care.