Background
Type 2 diabetes treated with insulin can be difficult to manage, especially when blood glucose levels fluctuate widely. Episodes of severe hyperglycemia, hypoglycemia, and diabetic ketoacidosis can lead to emergency visits and hospital admissions. In recent years, intermittently scanned continuous glucose monitoring, or isCGM, has become an important tool for helping patients and clinicians better understand glucose patterns, adjust insulin doses, and reduce the risk of complications. Unlike traditional finger-stick testing, isCGM allows users to scan a sensor worn on the body to see current glucose levels and recent trends throughout the day.
This study examined what happened when publicly funded isCGM was implemented on a large scale for adults with insulin-treated type 2 diabetes. The main question was whether wider access to this technology was associated with fewer hospitalizations, shorter hospital stays, and lower inpatient costs.
Study Design and Methods
This was a population-based, longitudinal, quasi-experimental cohort study. It included 15,413 adults with type 2 diabetes who used multiple daily insulin injections and started publicly funded isCGM between April 2022 and December 2023. The researchers followed hospitalization outcomes before and after isCGM initiation.
They focused on two major groups of hospitalizations. The first was acute diabetes-related complications, including diabetic ketoacidosis, hyperglycemic hyperosmolar state, simple hyperglycemia, and hypoglycemia. The second was cardiovascular complications, including myocardial infarction, stroke, and major lower-extremity amputation. These events were identified through ICD-10 diagnosis codes.
To estimate how hospitalization rates changed, the investigators used Poisson regression models and rate ratios. They also used interrupted time series analysis, a method that helps determine whether an intervention changes the direction or slope of a trend compared with what would have been expected without the intervention.
Who Was Included
The participants were adults with insulin-treated type 2 diabetes who were using multiple daily insulin injections. This is a group at higher risk for both low and high glucose episodes because their treatment requires frequent dose adjustments and close monitoring. The average follow-up period was 22.5 ± 4.6 months before isCGM initiation and 19.1 ± 4.4 months after initiation.
At baseline, the mean hemoglobin A1c (HbA1c), a measure of average blood glucose over the previous two to three months, was 8.09%. After starting isCGM, HbA1c decreased to 7.65%, representing an average reduction of 0.44 percentage points. This improvement suggests better overall glucose control after access to continuous glucose data.
Key Findings
The most notable result was a substantial reduction in hospitalizations for acute diabetes-related complications. The rate fell from 74.6 to 27.5 per 10,000 person-years, corresponding to a rate ratio of 0.37. In practical terms, this means the hospitalization rate was about 63% lower after isCGM initiation.
By contrast, cardiovascular hospitalization rates remained broadly stable overall, changing from 228.8 to 215.8 per 10,000 person-years. The rate ratio was 0.94, indicating no statistically meaningful overall difference in the crude before-and-after comparison. However, interrupted time series analysis did detect a change in cardiovascular admission trends after isCGM initiation relative to the preintervention trajectory. This suggests the pattern of admissions shifted over time, even if the overall average rate did not change dramatically during the study window.
The length of hospital stay also improved. The median stay decreased from 4 days to 3 days. Although this difference may seem modest, across thousands of admissions it can reflect meaningful reductions in illness severity, resource use, and patient burden.
The economic impact was equally important. Total inpatient costs decreased by $3,806,776.90, which translated to a reduction of $955,186.70 per 10,000 person-years. From a health system perspective, this suggests that broader use of isCGM may help offset some of its upfront costs by preventing expensive hospital admissions and shortening stays.
Why These Results Matter
These findings support the idea that glucose monitoring technology can improve more than laboratory values. Better glucose visibility may help patients detect rising or falling glucose earlier, adjust meals or insulin more safely, and seek care before a crisis develops. For clinicians, the additional data can make treatment decisions more precise and may lead to more individualized insulin management.
The reduction in acute diabetes-related hospitalizations is especially important because events such as severe hypoglycemia, hyperglycemia, and diabetic ketoacidosis are among the most preventable causes of emergency care in diabetes. Lowering these events can improve quality of life, reduce caregiver stress, and free up hospital resources.
The cardiovascular findings are more nuanced. Cardiovascular disease is influenced by many factors beyond glucose monitoring, including blood pressure, lipid control, smoking, obesity, kidney disease, and duration of diabetes. A change in hospitalization trends after isCGM introduction may reflect indirect benefits such as more stable glucose control, but it may also require longer follow-up to determine whether these early pattern changes translate into fewer major cardiovascular events.
Clinical Interpretation
This study suggests that making isCGM available to insulin-treated adults with type 2 diabetes can have a real-world benefit at the population level. The strongest signal was seen in acute diabetes-related admissions, where the decrease was large and clinically meaningful. The reduction in HbA1c supports the idea that improved glucose monitoring contributed to better day-to-day management.
Still, it is important to interpret the findings in context. This was not a randomized trial, so other factors occurring during the same period could have influenced outcomes. For example, changes in diabetes education, insulin prescribing patterns, access to specialist care, or broader health system policies may also have played a role. Even so, the large sample size and use of time-series methods strengthen the evidence that isCGM implementation was associated with improved outcomes.
Practical Implications for Patients and Health Systems
For patients, isCGM may help reduce the uncertainty of diabetes self-management. It can provide immediate feedback after meals, exercise, or insulin use, and may help people recognize dangerous patterns before they become emergencies. For people using multiple daily injections, this feedback can be especially valuable because treatment decisions are made frequently and errors can quickly affect glucose levels.
For health systems and policymakers, the study suggests that expanding access to isCGM may be a cost-saving or cost-offsetting strategy, particularly if it reduces preventable admissions. Public funding decisions should consider not only device costs but also potential savings from fewer hospitalizations, shorter stays, and improved diabetes control.
Education remains essential. Technology works best when patients understand how to interpret sensor readings, respond to trends, and use the information to adjust food intake, activity, and insulin safely. Access to diabetes educators and structured follow-up can help maximize the benefits of isCGM.
Limitations
As with any observational study, there are limitations. The before-and-after design cannot prove cause and effect with the same certainty as a randomized clinical trial. The study also relied on administrative codes to identify hospitalizations, which may occasionally misclassify events. In addition, the findings apply specifically to adults with type 2 diabetes who use multiple daily insulin injections and were eligible for publicly funded isCGM, so they may not generalize to all people with diabetes.
Another limitation is that hospitalization outcomes capture only the most serious complications. They do not fully reflect day-to-day benefits such as fewer hypoglycemic episodes at home, improved confidence, reduced anxiety, or better quality of life. Future studies could combine hospital data with patient-reported outcomes and longer-term cardiovascular follow-up.
Conclusion
In this large real-world study, implementation of intermittently scanned continuous glucose monitoring in insulin-treated adults with type 2 diabetes was associated with better glycemic control, fewer acute diabetes-related hospitalizations, shorter hospital stays, and lower inpatient costs. Cardiovascular hospitalization rates were more complex, showing no major overall crude reduction but a shift in trend after implementation.
Overall, the findings suggest that expanding access to isCGM may provide meaningful clinical and economic benefits for high-risk patients with type 2 diabetes who require intensive insulin therapy.
