Premixed Insulin May Offer Better Blood Sugar Control

WEDNESDAY Sept. 17, 2008 -- Premixed insulin, which combines short- and long-acting versions of the hormone, results in better blood-sugar control as compared with long-acting insulin alone or oral medications, a new study finds.

But it's not clear that this tighter glycemic control translates into fewer complications and a lower mortality rate among people suffering from type 2 diabetes, researchers add.

And two types of premixed insulin -- premixed human insulin and premixed insulin analogues (genetically engineered human insulin) -- appeared to produce the same benefit.

Various premixed products are already on the market, but the results described in a study in the Sept. 16 issue of Annals of Internal Medicine may help better determine which product benefits which patient.

More than a quarter of patients with type 2 diabetes use insulin alone (16 percent) or insulin combined with an oral medication (12 percent) to help them control their blood-glucose levels.

And as the number of people overall who have type 2 diabetes continues to increase, information on the effectiveness and safety of premixed insulin is even more imperative.

Premixed insulin includes both long- and short-acting insulin together in one preparation. These products are intended to give patients more flexibility as to when they eat.

"This is supposed to treat the post-meal sugar and also the blood sugars for eight to 12 hours after injection," explained Dr. Spyros Mezitis, an endocrinologist with Lenox Hill Hospital and assistant professor of medicine at New York Presbyterian Hospital/Cornell Medical Center in New York City. "It has more flexibility."

One injection of long-acting insulin would cover 24 hours, with four short-acting injections given in-between to cover meals.

With premixed, however, patients typically only need two injections: one before breakfast and one before dinner. The first injection covers breakfast and peaks at lunch but disappears by dinner time, at which time a second injection will take care of things until the next morning, explained study lead author Dr. Rehan Qayyum, assistant professor of medicine at Johns Hopkins School of Medicine in Baltimore.

This study was commissioned by the U.S. Agency for Healthcare Research and Quality.

After analyzing findings from 45 previous studies, the authors concluded that premixed insulin analogues and premixed human insulin provided similar blood-sugar control.

The analogues seemed to be more effective in lowering post-meal glucose levels, they said.

The premixed analogues also appeared to be more effective than long-acting insulin analogues and pills in decreasing hemoglobin A1c (a measure of blood-sugar control over time) and post-meal glucose levels.

On the other hand, premixed analogues appeared less effective than long-acting insulin, but better than oral pills, in decreasing fasting glucose levels.

"In terms of clinical practice, what it basically is saying is that if you want to replace premixed human insulin with premixed insulin analog, both seem to work pretty much the same," said Qayyum.

However, there will be individual patients who react differently to different formulations and may do better with long-acting insulin, for instance, he added.

Also, for individuals taking oral medications whose blood sugar is not well controlled, "premixed analogue is one option that can be looked at instead of titrating up or manipulating these oral diabetic agents," Qayyum said.

And, Qayyum emphasized, there is almost no data on how these benefits affect clinical outcomes, meaning the various, severe complications of diabetes such as death, blindness and kidney failure. Longer follow-up studies are needed to answer those questions, he said.

More information

There's more on type 2 diabetes at the American Diabetes Association.

Posted: September 2008


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