ADA: Sensor-Augmented Insulin Pump Therapy Wins Over Multiple Daily Injections for Type 1's

Treatment with a sensor-augmented insulin pump not only provided superior glucose control, it did so without any increase in hypoglycemia, said lead author Richard M. Bergenstal, MD, from the International Diabetes Center, Park Nicollet, Minneapolis, Minnesota. "The pump is considered an advanced way to deliver insulin for many people with Type 1 diabetes.... But what we looked at in this study is the next level -- of pump and sensor together. Pumps are great, but sensors are adding another level."

People with Type 1 diabetes all learn how to do multiple daily injections and the principles of managing their condition, including carbohydrate counting and blood glucose testing. But if they are not at goal after all of this, the question becomes what to do next, he said. "Should we just add a pump or just add a sensor? Or should we add a sensor and a pump? We decided to use the most advanced technology together to see how much improvement it would generate."

Sensor-augmented pump therapy integrates two technologies -- an insulin pump and continuous glucose monitoring -- into one system. It allows patients and their physicians to monitor treatment and response through Internet-based software.

The Sensor-Augmented Pump Therapy for A_1c Reduction (STAR 3) study involved 329 adults and 156 children between the ages of 7 and 70 years who had been on multiple daily injections that included a long-acting analogue insulin for the previous 3 months. They had a A1c level between 7.4% and 9.5%, and had been under the care of Dr. Bergenstal or a referring physician for at least 6 months.

The patients had to have access to a computer to participate in the trial.

They were randomly assigned to receive either pump therapy with the MiniMed Paradigm REAL-Time System (Medtronic) or to continue with their regimen of multiple daily injections under close supervision for the duration of the 1-year study.

All patients in the study also received training in intensive diabetes management, including carbohydrate counting and the administration of correction doses of insulin. Patients randomized to pump therapy were put on it for two weeks, and then, once they had become comfortable with the pump, the glucose sensor was added. This group used insulin aspart.

The injection-therapy group used both insulin glargine and insulin aspart.

All patients were seen at 3, 6, 9, and 12 months and used Carelink, a diabetes-management software program, to relay their blood glucose data to and communicate with their physicians from home.

"Here you see the importance of not only the technology, but the communication of the data back and forth. Sometimes, we give a patient a technology and then we send them home, with a 'good luck and hope it works.' In this trial, we wanted to know how things were working so we could help the patients adjust their treatment," Dr. Bergenstal said.

At one year, the investigators found that patients on pump therapy had hemoglobin A_1c levels that were significantly lower than the injection-therapy group. The baseline A1c level, which was 8.3% in the two study groups, had decreased to 7.5% in the pump therapy group, compared with 8.1% in the injection therapy group (P < .001).

The proportion of patients who reached the A1c target of below 7% was greater in the pump therapy group than in the injection therapy group. Among adults, the absolute reduction in the mean A1c level was 1.0% ± 0.7% in the pump-therapy group and 0.4% ± 0.8% in the injection-therapy group, for a between-group difference in the pump-therapy group of –0.6% (95% confidence interval, –0.8 to 0.4%; P < .001).

Rates of severe hypoglycemia and diabetic ketoacidosis were similar in both groups. There was no significant weight gain in either group or in either adults or children.

"It is the longest and largest randomized controlled study of sensor-augmented insulin pump therapy in Type 1 diabetes. We feel really good about the results we have obtained," Dr. Bergenstal said.

N Engl J Med. Published online June 29, 2010. American Diabetes Association (ADA) 70th Scientific Sessions.