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Study shows sensor helps achieve better glucose control than daily insulin injections

Dr. Robert Tanenberg
GREENVILLE, N.C.  (July 2, 2010)  —  A new type of insulin pump with a sensor can help adults and children with diabetes better manage their blood-sugar levels, according to research conducted at 30 trial sites, including East Carolina University, and published Tuesday, June 29, in the New England Journal of Medicine.

The significant decrease in A1C levels observed in the study, called STAR 3, for Sensor-Augmented Pump Therapy for A1C Reduction, occurred without an increase in the rate of hypoglycemia, or low glucose.

A1C testing is a way to measure blood-glucose levels. In individuals with poorly controlled diabetes, A1C levels are much higher than in healthy people. The study compared use of the sensor-augmented pump to the traditional method of multiple daily insulin injections.

Dr. Robert Tanenberg, a professor and diabetes specialist at the Brody School of Medicine at ECU and a principal investigator of the multicenter trial, said the sensor measures tissue glucose levels every five minutes and protects patients from having their blood-sugar levels dropping without them knowing it. That compares to patients who must prick their fingers to measure blood-sugar levels several times a day.

"If you had a sensor, you could probably carry on your life pretty easily," Tanenberg said. "The beauty of the sensor is it monitors blood sugar and shows a trend." Eleven ECU diabetes patients were enrolled in the 18-month study.

Study results were presented Tuesday, June 29, at the American Diabetes Association meeting in Orlando, Fla.

Nearly 44 percent of pediatric patients using sensor-augmented insulin pump therapy achieved age-specific glucose control targets, compared to only 20 percent of patients in the multiple daily injection group.

In addition, adult participants saw a 1 percent point reduction in their A1C levels. Every percentage-point drop in A1C blood test results can reduce the risk of complications by 40 percent. Uncontrolled glucose levels in patients with diabetes can lead to short- and long-term complications, including shakiness, confusion, fainting, blindness, kidney failure, limb amputation and, in rare cases, death.

Type 1 diabetes, or insulin-dependent diabetes mellitus or juvenile-onset diabetes, develops when the body's immune system destroys pancreatic beta cells, the only cells in the body that make the hormone insulin that regulates blood glucose. To survive, people with type 1 diabetes must have insulin delivered by injection or a pump.

Type 1 diabetes usually strikes children and young adults, although disease onset can occur at any age. In adults, type 1 diabetes accounts for 5–10 percent of all diagnosed cases of diabetes. About one in every 400 children and adolescents has type 1 diabetes.

An estimated 24 million Americans have type 1 or type 2 (adult-onset) diabetes, according to the American Diabetes Association. The prevalence is rising, and about a fifth of those with diabetes don’t know they have the disease. In the United States, the total annual economic cost of diabetes in 2007 was estimated to be $174 billion.

The study also showed patients on sensor-augmented insulin pump therapy demonstrated a reduction in mean A1C levels that was four times greater than the multiple daily injection group (0.8 percent study vs. 0.2 percent control). The mean A1C decrease was from a baseline of 8.3 percent to 7.5 percent in the sensor-augmented pump therapy group, compared to only 8.3 percent to 8.1 percent in the daily injection group.

The results demonstrated a strong link between increased sensor use and increased benefit. Patients who used the sensor with the insulin pump more than 81 percent of the time reduced their A1C levels by 1.2 percent.

Pumps have been used for years by some diabetes patients, but until recently they did not have sensors and required finger-sticks to measure glucose levels. Tanenberg hopes the study results will help convince insurance companies to fund these devices for patients with type 1 diabetes.

The study was sponsored by the medical device maker Medtronic and conducted at sites in the United States and Canada with participation from 485 patients (329 adult and156 children), ranging in age from 7 to 70.

The study is available online at http://content.nejm.org/cgi/content/full/NEJMoa1002853.

Contact: Doug Boyd | 252-744-2482