Project Summary

Type 2 diabetes (T2D) affects the lives of a huge number of Americans. Based on estimates from the Centers for Disease Control and Prevention, as of 2015, 30 million people in the US have diabetes, and more than 90 percent have T2D. Managing T2D requires a big commitment on the part of people with diabetes. Fortunately, the tools to help manage diabetes are improving. Hemoglobin A1c (A1C) testing—a lab test measuring the blood sugar, or glucose, stuck to hemoglobin in blood cells—helps indicate glucose control over the previous two to three months months, but doesn’t help in day-to-day management. Blood glucose fingerstick testing works better in evaluating changes in blood glucose over the course of the day but hasn’t been proven to help improve management for individuals not using insulin, and it can be painful and inconvenient.

Recently, a different technique to monitor blood glucose, continuous glucose monitoring (CGM), has become more available. Using CGM, glucose readings can be obtained as frequently as desired by using a reader or smartphone, allowing glucose to be checked painlessly and with greater convenience.

CGM can also record glucose values day and night, showing a graph of glucose values over 24 hours, and glucose patterns over two weeks. This glucose data can be accessed and easily viewed by patients and care teams. This data allows T2D to be managed both based on day-to-day glucose data and based on patterns over time.

Despite the fact that CGM is increasingly used by patients with T2D, it is not known whether CGM technology works as well, or better, than fingerstick testing in improving A1C and other important measures, especially in real-world primary care settings, where most T2D is managed.

This project will examine whether CGM works better than fingerstick testing to help manage T2D in a primary care setting. People will be divided into two groups based on which of 20 primary care clinics they attend. One group will use fingerstick testing to manage T2D in the way they find most useful and at a frequency recommended by their provider. The second group will use CGM for day-to-day glucose monitoring, also in the way they find most useful and as recommended by their provider. All participants will be asked to share blood glucose data with their provider at the time at clinic visits. To be included in the study, participants will have an initial A1C value of 7.5 percent to 12 percent, be between 18 and 75 years of age, and will be on medications that potentially cause low blood glucose (insulin or sulfonylurea medicine), making them more likely to benefit from blood glucose monitoring.

The project will compare the effect of CGM or fingerstick testing on glucose control by measuring A1C, and on diabetes-related stress using a survey called the Diabetes Distress Scale; these outcomes will be collected at baseline and 12 months. The team will also study what makes it easier, and what makes it more difficult, to use glucose data from fingerstick and CGM devices at clinic visits.

By collecting data at baseline and 12 months from a two-week blinded CGM device—one that doesn’t show real-time glucose numbers to the patient—this research will obtain other important measures of glucose control, including how much time on average the patient has optimal glucose range, and how much time is the patient has hypoglycemia.

Using surveys at baseline, three, and 12 months, this project will compare the two groups on measures they have told us are important, such as diabetes-related emotional stress, and to learn how these devices impact the day-to-day management of diabetes in terms of diet, exercise, self-management of diabetes, and quality of life.

This study will compare CGM or fingerstick testing on measures of blood glucose control and the burden of managing diabetes for patients. Throughout the study, patients and other stakeholders will help create processes that are sustainable and beneficial. The goal of this project is to produce meaningful evidence, generated in a real-world primary care setting, to help individuals with diabetes, caregivers, care teams, and payers, in choosing between these two technologies for monitoring and managing T2D.

Project Information

Richard Bergenstal, MD
Thomas Martens, MD
HealthPartners Institute

Key Dates

June 2020
December 2025


Award Type
Populations Populations PCORI is interested in research that seeks to better understand how different clinical and health system options work for different people. These populations are frequently studied in our portfolio or identified as being of interest by our stakeholders. View Glossary
Funding Opportunity Type
Research Priority Area
State State The state where the project originates, or where the primary institution or organization is located. View Glossary
Last updated: August 31, 2022