Which Is Better for Older Adults With Type 2 Diabetes: Insulin Pump Therapy or Insulin Injection Therapy?

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A clinical trial of continuous subcutaneous insulin infusion versus multiple daily injections in older adults with type 2 diabetes, by W.H. Herman and colleagues. Diabetes Care 28:1568–1573, 2005

What is the problem and what is known about it so far?

Both the American Diabetes Association and the American Geriatrics Society recommend that older adults maintain an A1C level (a measure of long-term blood glucose) in a healthy range (less than 7%). However, surveys have shown that only one-third of patients with diabetes who were between 65 and 74 years of age had A1C levels in a healthy range, and of those people who were taking insulin, only 27% had A1C levels in a healthy range.

When diet, exercise, and glucose-lowering pills aren’t enough to control blood glucose levels, patients with type 2 diabetes often need to take insulin to control their diabetes. Patients who take insulin use either traditional insulin injections (using either a syringe or an injection pen) or an insulin pump. An insulin pump is a portable device that injects insulin at timed intervals in order to control blood glucose levels. Unfortunately, previous studies have not looked at which type of insulin therapy -- insulin injection therapy or insulin pump therapy -- is safer and better for controlling blood glucose levels in older adults with type 2 diabetes.

Why did the researchers do this particular study?

The researchers wanted to see whether insulin injection therapy or insulin pump therapy is safer and better for controlling blood glucose levels in older adults with type 2 diabetes.

Who was studied?

More than 100 adults who were older than 60 years of age and were taking insulin to control type 2 diabetes. On average, the patients had type 2 diabetes for 16 years, were overweight, and had a high A1C level (8.2%). In addition, the patients were taking at least one insulin shot each day during the month before the study started.

How was the study done?

Patients were chosen to receive intense insulin therapy using either an insulin pump or insulin injections. Over 12 months, the researchers checked the patients' A1C levels, how many times they had severe hypoglycemia (or dangerously low blood glucose levels, sometimes known as an “insulin reaction”), and whether the patients were satisfied with their type of insulin therapy. Study staff regularly instructed the patients about intense insulin therapy with either insulin injections or an insulin pump. They also instructed the patients on how to monitor their blood glucose levels, diet, and physical activity.

What did the researchers find?

Forty-eight patients in the insulin pump group and 50 patients in the insulin injection group finished the study. In both the insulin pump group and the insulin injection group, the average A1C level dropped into the healthy range (below 7%); the average A1C in the insulin pump group was 6.6%, and it was 6.4% in the insulin injection group.

The majority of patients in each group had minor lows in their blood glucose levels, and only a few patients in each group had dangerous lows in their blood glucose levels.

Patients in both groups were satisfied with their types of insulin therapy.

What were the limitations of the study?

In this study, there were more men in the insulin pump group, and the patients in the insulin pump group had higher A1C levels at the beginning of the study. The researchers, though, noted these differences when looking at the results and implications of the study.

What are the implications of the study?

For patients who are older than 60 years of age and take insulin to treat type 2 diabetes, intense insulin therapy using either insulin injections or an insulin pump is safe and effective at controlling blood glucose levels.

FOR MORE INFORMATION

Insulin Pumps

A randomized, prospective trial comparing the efficacy of continuous subcutaneous insulin infusion with multiple daily injections using insulin glargine, by E. Doyle and colleagues. Diabetes Care 27:1554–1558, 2004.

Insulin Routines

Smart Pumping for People with Diabetes. Howard Wolpert, Ed. (Alexandria, Va., ADA, 2002).

A1C Test