Major Finding: Mean HbA1c decreased from 8.3% to 7.5% with the use of a sensor-augmented pump vs. 8.1% with multiple daily injections.
Data Source: Randomized, controlled trial with 485 patients.
Disclosures: The study was funded by Medtronic MiniMed, maker of an insulin pump and continuous glucose monitor system. Several investigators disclosed that they have earned consulting fees, honoraria, grants, or travel reimbursements from numerous pharmaceutical companies and device manufacturers, including Medtronic, Bayer Healthcare, Lifescan, Novo Nordisk, and Becton Dickson. Those companies also supplied the study with insulin aspart and glucose monitors. Dr. Wolpert disclosed having been a consultant to Abbott, Novo Nordisk, and Insulet.
ORLANDO — Sensor-augmented insulin pump therapy resulted in significant improvements in hemoglobin A1c levels without increasing hypoglycemia, compared with multiple daily injection therapy, in a 1-year randomized, controlled trial of 485 patients with type 1 diabetes.
Participants in the prospective, multicenter Sensor-Augmented Pump Therapy for A1c Reduction (STAR)–3 study were seen at 30 sites in the United States and Canada. All patients (aged 7-70 years) had type 1 diabetes treated with multiple daily injections that included a long-acting analogue insulin during the previous 3 months and had an HbA1c value between 7.4% and 9.5% (mean 8.3% in both groups), Dr. Richard M. Bergenstal reported. The findings were published simultaneously in the New England Journal of Medicine online on June 29 (doi:10.1056/NEJMoa1002853).
All patients received intensive diabetes management training, with the sensor-augmented pump group receiving additional training in the use of the pump. The multiple daily injections (MDI) group wore a continuous glucose monitor that did not display glucose data to the patient. Both groups downloaded their data to an online software system.
For the study's primary end point, change in HbA1c between the sensor-augmented pump and multiple daily injection groups at 1 year, results were highly significant: The mean HbA1c decreased from 8.3% to 7.5% in the sensor-augmented pump group and to 8.1% in the MDI group, translating to a fourfold greater reduction with the sensor-augmented pump, said Dr. Bergenstal, executive director of the International Diabetes Center in Minneapolis.
In the 329 adults aged 19 and older, mean HbA1c was decreased to 7.3%, compared with 7.9% in the MDI group. In the 156 children and adolescents aged 7-18 years, the value was reduced to 7.9% with sensor-augmented pump vs. a slight increase to 8.5% with MDI.
The adult group had achieved that 7.3% value within 3 months and had remained consistent over the entire year; the children and adolescents achieved a mean of 7.5% at 3 months, but the value then drifted upward. However, in the pediatric group the 1-year difference from baseline was still statistically significant, noted Dr. Bergenstal, the ADA's president for medicine and science.
A linear relationship was seen between sensor use and HbA1c, with reductions of just 0.19 percentage points among those who wore the sensor 21%-40% of the time, compared with a reduction of 1.21 percentage points in those who wore it 81% of the time or more. Results were statistically significant in those who wore the sensor 41% of the time or more, he said.
The proportion of patients who achieved an HbA1c value of 7% or less at 1 year was 27% with sensor-augmented pump, compared with 10% with MDI, a highly significant difference. In adults, the difference was 34% vs. 12%. In the children and adolescents, the proportions achieving the ADA recommendations of less than 7.5% for those aged 13-19 years and less than 8% for 6- to 12-year-olds were 44% with sensor-augmented pump and 20% with MDI.
Diabetic ketoacidosis was rare in both groups and did not differ between the groups. The amount of time spent in hypoglycemia also did not differ between the two groups. Severe hypoglycemia occurred in 13.31 patients per 100 person-years in the sensor-augmented pump group, compared with 13.48 patients in the MDI group. Among the adults, weight gain was greater with SAP, at 2.4 kg, compared with 1.8 kg with MDI, Dr. Bergenstal said.
In an editorial that accompanied the study report, Dr. Howard Wolpert of the Joslin Diabetes Center, Boston, noted that “continuous glucose monitoring can be viewed as a compass that tells patients where their glucose is heading. However, to reach that goal, patients need to be skilled in diabetes self-management. The expert training and guidance received by patients in clinical trials cannot be readily duplicated in a busy clinical practice,” he said (N. Engl J. Med. 2010 June 29; doi:10.1056/NEJMe1006098).
The benefits of improved glucose control must also be weighed against the demands that the technology places on the patient, he wrote.