Overuse of Basal Insulin Is a Common Problem in Type 2 Diabetes, Research Suggests

Diabetes is a complicated condition that can be difficult for some people to fully understand, especially when it comes to all the treatment options out there and the different ways those treatment options impact your body.

However, it can also be very important to take the time to consider different treatment options, because, over time, your body may need something different than what your doctor originally told you to do. Neglecting to make the changes that your body needs may mean worse health complications down the road.

Recent research has shown that “overbasalization,” or the overuse of basal insulin in place of other more appropriate therapies, is very common in people with type 2 diabetes. When overbasalization occurs, a person’s hemoglobin A1c spikes above eight percent despite the use of more than 0.5 units/kg per day of basal insulin.

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In these situations, it is often more prudent for a patient to be on another diabetes therapy, whether insulin or a non-insulin drug, that specifically targets mealtime blood glucose spikes. Continuing to take basal insulin in place of a faster-acting insulin or a drug like metformin in these circumstances can impede the person’s ability to achieve optimal glycemic control.

Researchers led by Kevin Cowart, PharmD, a diabetes care and education specialist at the University of South Florida, Tampa, found that overbasalization was occurring in about 40 percent of type 2 diabetes patients they investigated in a primary care clinic in Florida from 2015 to 2018. For at least a year, they followed 655 adults with type 2 diabetes who were being given basal insulin. They had a mean HbA1c of 8.4% and a mean basal insulin dose of 0.4 units/kg per day.

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For those patients with an HbA1c above eight percent, researchers found that the rate of overbasalization was 38.1 perent. For those with an HbA1c above nine percent, 42.7 percent were overbasalizing. And for patients whose HbA1c was above 10 percent, overbasalization was occurring in 42 percent.

Cowart says if people with type 2 diabetes do not achieve an HbA1c target of 7 percent or lower within the first year of starting a basal insulin therapy, it’s not likely that they’ll ever achieve that goal. After a year, they only have a 7 percent chance of achieving it, which continues to diminish the longer their HbA1c number stays high.

It’s important for type 2 diabetes patients to be put on other therapies at this point, whether in addition to or in place of basal insulin, so that they can get their blood sugar under control. But many are not.

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“Our analysis suggests that overbasalization plays a role in patients with type 2 diabetes on basal insulin not achieving optimal glycemic control,” says Cowart. “Basal insulin is not designed to address postprandial hyperglycemia. I think there’s a clear need to address hesitancy in therapeutic progression beyond basal insulin. A lot of factors underlie the delays, with therapeutic inertia being one of them. It’s complex.”

This research should be a lesson to both doctors and patients. Basal insulin is a fine thing to try, but HbA1c levels should continue to be monitored so that the patient and doctor know when it’s time to try something different.

“It’s kind of that wall that patients with type 2 diabetes hit because their A1c is high but their fasting blood sugars are normal,” says Rozalina G. McCoy, MD, an endocrinologist and primary care clinician at the Mayo Clinic. “Sometimes it’s assumed that there’s a discrepancy, because people don’t always think about postprandial hyperglycemia.”

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Dr. McCoy also says that there’s been a push recently to simplify treatment regimens in older adults with diabetes. This can be a good thing, but failing to see results over time still means something needs to change.

“We really want to avoid rapid-acting insulin in older patients because we’re afraid of hypoglycemia, so we start them on basal and keep the non-insulins like metformin and sulfonylureas around,” she says. “Initially, those control the postprandial blood sugar, but over time, they’re no longer enough.”

If you think you may be overbasalizing, talk to your doctor about getting your HbA1c checked and what other therapies you might be able to try.

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