June 24, 2001 (Philadelphia) -- Despite promising early results in both animals and people, low-dose insulin shots do not appear to delay or prevent type 1 diabetes in people at high risk of developing the disease, according to research presented here at the annual meeting of the American Diabetes Association.
The study, dubbed the Diabetes Prevention Trial (DPT-1), followed more than 300 children who were diagnosed with having a 50% or higher chance of developing type 1 diabetes within five years. Half of the kids received intravenous insulin for four days, and then got low-dose insulin shots twice daily for nearly four years. The other half of the group received no treatment but was closely watched by investigators.
The children were deemed high risk because they tested positive for several blood markers of diabetes risk and negative for a gene thought to protect people from developing the diabetes.
Disappointingly, both groups had approximately the same rate of progression to diabetes, says lead researcher Jay S. Skylar, MD, professor of medicine, pediatrics, and psychology at the University of Miami.
There were no harmful effects in giving the low-dose insulin shots but, unfortunately, no beneficial effects either, Skylar says.
The good news? Because of the close monitoring of study participants, the doctors were able to diagnose the disease at a much earlier, symptomless stage.
As many as one million Americans have type 1 diabetes, which usually begins in childhood. It occurs when the body's immune system mistakenly launches a deadly attack on its own cells that produce the vital hormone insulin.
The initial hope was that the low-dose insulin shots would give these insulin-producing cells a time-out. It was thought that when they are resting, they are less likely to be destroyed by an immune system attack.
But no such luck: 15.1% in the insulin group and 14.6% in the control group developed diabetes, the study found.
Calling it a "beautifully done study," ADA president-elect Christopher Saudek, MD, says, "I am disappointed that this didn't prevent diabetes, [but] we can't afford to be discouraged and have to proceed with other such trials." Saudek is professor of medicine at Johns Hopkins University in Baltimore.
Skylar says he would like to continue following these patients for the next seven years to see if they have lower rates of diabetes complications and/or milder forms of the illness.
Despite the negative results of the insulin shot study, Skylar is optimistic about a new trial that looks at the possible preventive effects of an experimental insulin pill that dissolves in the mouth. This new study looks at people who are at far less risk of developing diabetes than those included in the previous trial, and the insulin is being given earlier in the disease process.
Skylar hopes the insulin pill will interfere early on with the immune system's attack against itself. Enrollment in this study is ongoing, and preliminary results are expected within two or three years.
For more information on the oral insulin trial, call 1-800-HALT-DM1 (1-800-425-8361).