Diabetes Health Center

Convenient Care: The Insulin Pump

There's no substitute for the body's own blood sugar control mechanism, but insulin pumps may be the next best thing, say diabetes experts.

An insulin pump is a compact, pager-sized, computerized device that can be worn on a belt. It is connected to the body via a flexible plastic tube through which insulin is delivered. The pump releases insulin in a steady, continuous background or "basal" dose, but also allows the wearer to add an additional dose, or "bolus" of insulin when needed, such as before a meal or snack.

"It provides more stable insulin deliveries and smoothes out glucose fluctuation compared with injections," explains Howard A. Wolpert, MD, senior physician and director of the insulin pump program at the Joslin Diabetes Center in Boston, in an interview with WebMD. "I think the advantage from a lifestyle standpoint is what attracts many people, because it does allow people much more flexibility in terms of eating times."

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Although people with diabetes can now use an ultra long-lasting insulin (insulin glargine) that releases an even basal dose for 24 hours after injection, Wolpert notes that "with glargine people still need to take multiple injections whenever they're going out to eat or whenever they're going to have a snack. With a pump it's much more convenient in terms of just having to press a button and get insulin delivered. For people eating out, if they're not certain what they're going to be eating they can take an initial bolus or pulse of insulin, and as the meal proceeds they can take further insulin depending on their [food] intake."

The pump also can help control the release of glucose during exercise, Wolpert says. Insulin levels normally drop during exercise to allow the release of stored glucose for use by the exercising muscles, but people who inject insulin may find it hard to predict how much insulin to have on board prior to exercise. In contrast, those who use pumps can more easily adjust the dose to their body's minute-to-minute-demands. "For the motivated patient who wants to lose weight through exercise, one can do it much more effectively if one's on a pump than say on insulin injection," Wolpert tells WebMD.

But while the insulin pump is for many people an improvement over multiple daily injections, it requires a dedicated and savvy operator to make it work. The user still has to perform multiple daily blood tests to check for glucose levels, and must know how to program in the right insulin dose after each test; currently available pumps can neither sense current glucose levels nor can they automatically adjust insulin levels.

"It's just a different tool for delivering insulin; the person still needs to input the doses, and to get the most out of the pump one still has to be pretty knowledgeable and skilled in diabetes self-management. It's not a tool for the novice," Wolpert says.

"It isn't right for everyone," agrees Michael Freemark, MD, professor of pediatrics and chief of the endocrine and diabetes division at Duke University Medical Center in Durham, N.C. "It requires a strongly committed family and an experienced diabetes team."