June 8, 2000 -- A new study confirms that insulin pumps are more effective than multiple daily insulin shots at helping type 1 diabetics' control their blood sugar and can lower the total daily insulin dose they need. This is especially true if the patients take a large portion of the dose at mealtimes, says the study, published in the journal Endocrine Practice.
Diabetics' bodies fail to produce enough of the hormone insulin, which regulates blood sugar. Without insulin, blood sugar stays dangerously high, and can cause serious complications, including blindness and kidney failure. Type 1 diabetes usually occurs in childhood, and people with this type of diabetes must take insulin to stay in good health. Insulin can be taken by injection or by the pumps, devices worn like a fanny-pack that deliver programmed doses of the drug under the skin of the wearer's abdomen.
For the study, Linda M. Crawford, BA, of the Dartmouth Medical School, in Lebanon, N.H., and colleagues reviewed the cases of 19 people with type 1 diabetes. The patients, aged 30-58, had switched from a multiple-shot regimen to an insulin pump system between 1991 and 1997. Most had asked to be put on pump therapy to improve their blood sugar control and to reduce the frequency of their bouts of low blood sugar.
The patients started with a daily insulin dose equaling 80% of that they had been taking before going on the pumps. Half the dose was given throughout the day as "background" insulin, and the other half was given at mealtimes. The patients checked their blood sugar levels six to seven times a day. They were followed for an average of 14 months.
The researchers found that HbA1C , an important measure of the patients' blood sugar, significantly decreased after they switched to the pump. Their weight also decreased, from an average of 153 pounds at the beginning of the study to 152 pounds. And their total daily dose of insulin decreased by some 18%.
One interesting finding was that the amount of insulin the participants used between meals decreased, while the amount used at mealtimes increased. The patients achieved appropriate premeal doses by more closely monitoring their own blood sugar and by counting carbohydrates, the study's authors say.
"This article confirms what others have confirmed: that with the pump, we can lower HbA1C, which means improving [blood sugar] control," says Bruce Bode, MD, who reviewed the study for WebMD. "That translates into a reduction in complications." Bode is an endocrinologist at Atlanta Diabetes Associates and medical director of the Diabetes Resource Center at Piedmont Hospital, also in Atlanta. He is also a consultant for Mini-Med, an insulin pump manufacturer, and for insulin makers Novo and Eli Lilly.
While Paul Jellinger, MD, FACE, president of the American Academy of Clinical Endocrinologists, says experts have known for a while that patients on pumps require less insulin, study co-author Rita Odell, MEd, says "the reduction of insulin overall and the matching of insulin to food was a very positive outcome."
Patients who are deciding whether to switch to a pump should think about why they want one, Bode says. "The main reason to use a pump is that you want to improve your blood sugar control and have more flexibility in your lifestyle -- to be able to eat, sleep, and work when you want. But someone who's not going to check their glucose shouldn't go on it."
The pump is not for everyone, Jellinger says. "Many patients prefer not to be attached to things. There's no mandate to put a patient on the pump if they're doing well on [shots]. The best candidates are patients that ask to go on a pump."
A big advantage of the pump is that it uses only the shorter-acting insulin, which gives a more predictable result than the longer-acting kind used by patients on injections, says Bode. Using short-acting insulin lessens the chance of making your blood sugar too low.
Irl Hirsch, MD, of the Diabetes Care Center at the University of Washington, in Seattle, notes in an editorial accompanying the study that many physicians still struggle to get reimbursed for services related to switching patients to pumps, such as counseling by nutritionists and nurse-educators. "These important and talented personnel are required for all patients with diabetes, regardless of the type of diabetes and the type of medications used," he writes.
He also questions the authors' assertion that all the study patients were measuring their blood sugar six to seven times daily, and wonders whether the frequency of home testing increased when the patients were using pumps. "Obviously, an increase in self-monitoring of [blood sugar] could account for some of the improved results," Hirsch writes.
- A new study shows that an insulin pump may be a better way for people with type 1 diabetes to control their blood sugar than daily injections of insulin.
- Using the insulin pump requires careful monitoring of blood sugar levels, so diabetics should switch to an insulin pump only if they are willing to do this.
- Another advantage to the insulin pump is more lifestyle flexibility.