Medtronic Insulin Pump Cuts Deadly Night Blood Sugar Lows

Medtronic Inc.’s advanced insulin pump can safely shut itself off when a patient’s blood sugar gets too low, according to a study hailed as breakthrough in the effort to automate insulin delivery for Type 1 diabetics.

The feature known as “threshold suspend” stops insulin delivery for two hours after blood sugar drops to a dangerous level. The study presented at the American Diabetes Association’s annual meeting in Chicago found insulin pumps with the suspend function slashed low blood-sugar levels at night by 32 percent compared with those that didn’t have it.

Researchers have been working for a decade to integrate insulin pumps with continuous glucose monitors. The technology is designed to replace the pancreas, the organ that when healthy produces insulin needed to convert blood sugar to energy. The three-month study funded by Minneapolis-based Medtronic is the first rigorous trial to show the device can independently sense low blood-sugar levels and adjust insulin delivery accordingly.

“This technology promises to be valuable to patients today and is a key step in the development of a fully automated artificial pancreas for people with diabetes,” said Rich Bergenstal, executive director of the International Diabetes Center at Park Nicollet in St. Louis Park, Minnesota.

The company and investigators now are working on a more sophisticated program to anticipate blood-sugar levels and ensure they stay in the ideal range, including the ability to increase insulin delivery when blood sugar is too high, he said in a statement. Eventually they hope to craft a pump that can supply other hormones that affect blood-sugar levels and adjust for factors such as exercise and diet, he said.

FDA Filing

Medtronic has filed for U.S. Food and Drug Administration approval of its MiniMed 530 G system that includes the threshold suspend technology. It has been sold outside of the U.S. since 2009 as the MiniMed Veo System.

The study, also published today in the New England Journal of Medicine, shows the novel pump doesn’t cause harm by turning off the insulin temporarily. An alarm sounds when the low blood-sugar level is hit, and the patient can take other action, like eating or drinking, to correct the problem. About half the time the insulin was stopped for just 10 minutes.

Sometimes, however, patients sleep through the alarm. Ten percent of the time the insulin remained halted for the entire two hours. Low blood sugar, called hypoglycemia, is particularly dangerous at night because lack of treatment can cause seizures, a coma and death.

Patient Win

“Automating any insulin delivery can be a win for the patient,” said Francine Kaufman, vice president of global medical affairs in Medtronic’s diabetes business, in a telephone interview. “It doesn’t take much more than intuition to know that stopping insulin when someone is on their way to being too low is a good thing,” she said.

The feature is just the first of many steps that will be needed to fully automate insulin delivery and create a closed-loop artificial pancreas, she said.

Checks showed the suspensions didn’t lead to excessively high blood sugar two to four hours later. Overall, the patients’ glucose control didn’t suffer, the researchers said. Episodes of hypoglycemia that did occur were shorter and less severe. There were four cases of severe hypoglycemia in the study, all in patients with insulin pumps that didn’t have the suspend feature.

The reduction in the number and severity of hypoglycemic episodes with the pump may have future benefits. Previous studies suggested hypoglycemia may predispose patients to more severe, future low blood-sugar episodes, the researchers said.

About 5 percent of the 25.8 million Americans with diabetes have the Type 1 form, where the body doesn’t produce insulin. The condition is typically diagnosed in children and young adults.

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