CGM vs BGM in GLP-1 Trials: Data Quality, Compliance, and Operational eCOA Realities

A YPrime Blog By:

Karl McEvoy, PhD
Vice President, eCOA and Patient Technologies,
YPrime

Aubrey Verna
Senior Product Director,
YPrime

As GLP-1 therapies expand across indications like obesity, cardiovascular disease, and rare metabolic conditions, clinical trial teams are faced with critical decisions about how to monitor glucose effectively. When evaluating eCOA glucometer integrations, continuous glucose monitoring (CGM) and blood glucose meters (BGM) each offer distinct advantages—but the choice of device is just the beginning.

For clinical trial sponsors, the larger question is not just CGM versus BGM—but whether their eCOA vendor can reliably support glucose monitoring at scale, across devices, regions, and regulatory expectations.

In trials that include glucose monitoring, collecting the data is only step one. Ensuring that data is reliable, compliant, and operationally sustainable requires alignment across clinical, technical, and operational stakeholders—from participant training and adherence, to eCOA system configuration, device integration, data ingestion, and visualization workflows.

In a recent article in Applied Clinical Trials, we examined the fundamental differences between CGM (continuous glucose monitoring) and BGM (blood glucose meters), highlighting their respective roles in clinical trials—especially those evaluating GLP-1 therapies. Here, we focus on what comes after device selection: how eCOA platforms manage glucose data, minimize loss, support patient compliance, and execute consistently across global diabetes trials.

Data Volume: What Happens When You Scale?

Let’s start with the numbers. A CGM device collecting data every five minutes will generate approximately 105,120 data points per patient during a year-long study—compared to fewer than 1,825 data points per patient per year with BGM.

This creates two immediate challenges:

Infrastructure readiness: Many legacy data systems struggle with passive, high-frequency data collection. Traditional flat file transfers aren’t designed to handle this volume.

Visualization and analytics: Teams need purpose-built dashboards and filtering capabilities to extract trends and drive decisions—without drowning in data.

CGM data enables rich insights into glycemic variability, time in range, and safety indicators, but only if the infrastructure supports real-time ingestion, transformation, and review. Sponsors need to ensure that both data volume and data use are accounted for in protocol planning and vendor selection.

Minimizing Data Loss: Different Devices, Different Risks

All glucose monitoring carries some risk of missing data, but the implications differ by device type and how the eCOA platform manages those risks:

With BGM, every reading carries more weight. Missed finger sticks, syncing failures, or connectivity issues can have an outsized impact on data completeness. Fortunately, experienced eCOA vendors provide built-in mitigation strategies, including compliance alerts, visit reminders, training reinforcement, and real-time monitoring.

With CGM, data gaps often result from sensor detachment, adhesion challenges, calibration errors, or device handling issues. While a single day of missing CGM data may represent hundreds of readings, the overall impact may be less critical due to continuous collection. Still, eCOA platforms must be able to detect gaps, flag anomalies, and support rapid site or patient intervention.

Planning for data loss is not optional—it is a core part of eCOA design for diabetes and metabolic trials.

Participant Compliance: Where eCOA Design Makes or Breaks Data Quality

Participant burden directly influences data quality, and eCOA usability plays a decisive role.

For BGM, the challenge is sustained engagement. Repeated finger sticks—especially multiple times per day—can lead to fatigue, missed readings, and attrition over longer studies. eCOA systems that support flexible entry windows, reminders, and real-time compliance tracking help mitigate this risk.

For CGM, the burden shifts. While data collection is passive, patients must manage sensor placement, replacement, Bluetooth connectivity, and skin tolerance. An eCOA platform experienced in CGM trials must support device pairing workflows, troubleshooting pathways, and clear participant guidance.

From pediatric populations—where reducing finger sticks improves quality of life—to elderly patients already comfortable with BGM, eCOA vendors must design participant workflows that align with real-world diabetes management.

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Global Reach and Regulatory Consideration for eCOA-Based Glucose Monitoring

Device strategy becomes even more complex at global scale.

BGM benefits from broad availability, standardized models, and established regulatory acceptance worldwide. CGM, while increasingly approved, often requires more nuanced planning. In label-enabling trials, CGM use has frequently been paired with concurrent BGM data to support validation and calibration.

For sponsors, this places added importance on selecting an eCOA vendor with proven experience supporting glucose monitoring across regions, regulatory bodies, and device ecosystems. Regional differences in reimbursement, site familiarity, logistics, and patient acceptance must all be factored into deployment plans.

CGM Is Not a One-Click Upgrade, especially in eCOA

It is tempting to view CGM as a simple upgrade from BGM. In reality, CGM introduces a different—and more demanding—eCOA operating model.

When evaluating CGM or BGM as part of an eCOA strategy, clinical trial sponsors must ask:

Are we collecting the right data, not just more of it?

Do our endpoints justify continuous monitoring?

Can our eCOA platform ingest, visualize, and validate this data efficiently?

For clinical trials trials where point-in-time glucose measurements support primary endpoints, BGM remains a reliable and efficient choice. For studies focused on glycemic variability, longitudinal response, or safety trends, CGM offers depth—but only when paired with an eCOA vendor built for device-driven data complexity.

What Sponsors Should Expect from an eCOA Vendor Supporting Glucose Monitoring

Sponsors running GLP-1 and diabetes trials should expect their eCOA vendor to do more than collect glucose data. Proven vendors bring experience integrating CGM and BGM devices, managing high-frequency data at scale, supporting participant compliance, and delivering audit-ready datasets across regions.

Most importantly, the eCOA platform must be designed to support glucose monitoring as a core workflow—not as a bolt-on—so sponsors can execute confidently from first patient in through data lock.

Final Takeaway for Clinical Trial Sponsors Evaluating eCOA Vendors

No matter which glucose monitoring approach is selected, success depends on more than device specifications. It requires an eCOA platform designed for diabetes trials, capable of integrating BGM and CGM data, supporting participant compliance, and delivering inspection-ready data at scale.

Sponsors evaluating eCOA vendors for GLP-1 and diabetes trials should prioritize partners with demonstrated experience in glucose monitoring—not just generic eCOA capabilities.

Whether you are designing your first glucose-enabled study or scaling across multiple GLP-1 indications, the strongest strategies start with the right eCOA foundation.

YPrime’s eCOA platform is built to support glucose monitoring across BGM and CGM, with proven experience integrating devices, managing high-volume data, and supporting global diabetes trials from startup through data lock.

Frequently Asked Questions: eCOA, CGM, and BGM in Diabetes & GLP-1 Trials

What should sponsors look for in an eCOA vendor supporting glucose monitoring trials?

Sponsors should look for eCOA vendors with demonstrated experience integrating both CGM and BGM devices, managing high-volume glucose data, and supporting diabetes and GLP-1 trials across regions. Beyond device connectivity, the eCOA platform must support compliance tracking, data validation, visualization, and inspection-ready reporting aligned with regulatory expectations.

Can eCOA platforms support both CGM and BGM within the same clinical trial?

Yes, but not all eCOA platforms are designed to do so effectively. Sponsors running hybrid glucose monitoring strategies should ensure their eCOA vendor can ingest and manage continuous CGM data alongside point-in-time BGM entries, while maintaining data integrity, traceability, and consistent review workflows.

What are the biggest eCOA challenges when using CGM in GLP-1 trials?

The primary challenges include managing high-frequency data volume, detecting and addressing data gaps, supporting device pairing and troubleshooting, and presenting actionable insights without overwhelming sites or monitors. An eCOA platform purpose-built for device data is critical to mitigating these risks.

Is BGM still a viable option in diabetes and GLP-1 clinical trials?

Yes. BGM remains a trusted and effective option for trials where point-in-time glucose measurements support primary endpoints. When paired with an eCOA platform that includes reminders, compliance alerts, and flexible entry windows, BGM can deliver high-quality, reliable data with lower operational complexity.

How does eCOA design impact patient compliance in glucose monitoring trials?

eCOA design plays a central role in compliance. For BGM, features such as reminders and real-time compliance tracking help reduce missed readings. For CGM, eCOA platforms must support clear device workflows, pairing guidance, and rapid issue resolution to prevent data loss and participant frustration.

Why is eCOA vendor experience in diabetes trials important for sponsors?

Diabetes and GLP-1 clinical trials introduce unique challenges related to device use, data volume, participant behavior, and regulatory scrutiny. Clinical trial sponsors benefit from eCOA vendors who understand these realities and can design workflows, integrations, and oversight models that scale from study startup through data lock.