Diabetes News Week of June 25, 2000

SpectRx Shows Continuous Monitoring Device

In testing, an individual with diabetes wore two of the devices, one patched on the arm and one on the abdomen. Each device had its own read-out screen connected to the patch with tubing. The read-out screens were attached side-by-side to the wearer's belt. The blood sugar readings on the screens were similar, and the wearer reported they were also similar to finger-stick testing done with a regular monitor.  

SpectRx is still in clinical trials with their device and project it will take one to two years before they bring their product to market. They are partnered with Abbott Laboratories in the development, who also make the Medisense meters. The company says it is trying to price the refined and miniaturized consumer 3-day device at the cost of current four times a day testing. A radio transmitter is planned to transmit readings to a watch-like device to replace the tubing shown in the picture. Read more about this technology on our New Blood Sugar Monitoring Technology page.

Diabetes And Human Genome Mapping

Scientists announced they have finished the first big step toward mapping the human genetic code. This public and private effort has been in the works for 10 years and is just the beginning of a process that will transform medicine, as well as other aspects of our lives.

The public part of this endeavor is the Human Genome Project, an international effort funded by the government and universities. They report they have finished a rough draft of the genome sequence and 85 percent of the assembly.

The private part is Celera Genomics Inc., a company in Rockville, Maryland founded with the specific purpose of being the first to map the human genome. They say they have finished the sequence and assembled the genetic code.

Celera was founded when one of the Human Genome Project researchers, Craig Venter, broke away from the group to set up a company to do the same work. His concern was that the government funded research was taking too long and that a private company could do the same work more quickly.

Celera has done the first step in a matter of months. Starting in September, Venter's team of scientists with the help of sophisticated scanners have analyzed, read and assembled all 3 billion letters of genetic code taken from five men and women of different ethnic backgrounds.

Though controversy has swirled around the ownership of the information, the two groups have said they will publish it jointly later this year in a scientific journal. After publication, both teams of researchers will join for a conference in which they will compare their findings and determine how to proceed.

What will mapping and sequencing of the gene code mean for people with diabetes? It will radically change medicine by allowing doctors to find the location of the genes or parts of genes where problems arise. Where genetics plays a strong role, it will enable doctors to determine an individual's susceptibility to diabetes and predict who is prone to developing the disease, and who may develop complications and which ones. 

Much work is already underway in identifying the genes linked to diabetes and its complications. By identifying the genes involved, much better medications for treatment will eventually become available. Inherent problems exist in this approach, however. For instance, in Type 1 diabetes, only about 25% of cases appear to have a strong genetic link. The remaining 75% appear to occur at random with little familial indication of susceptibility. These cases may be triggered by environmental factors, without any strong genetic link. 

In Type 2, just the opposite problem appears. About 25% of the American population appears to have genes which make them susceptible to insulin resistance, the root cause of most Type 2. Whether the individuals within this large group who go on to develop diabetes can be clearly identified may take some time to answer. Eventually, doctors hope to make changes in the genes to overcome diabetes and its problems. As long as the disease exists, the hope is to tailor drugs and treatment for each individual.

Metformin Tested In Type 2 Children

Is metformin safe and effective for use in children with Type 2 diabetes?

Although metformin, an oral diabetes medication, has been used for nearly 50 years by adults with Type 2, it has never been formally studied in children with Type 2. But with Type 2 in children on the increase, the need to know the effectiveness of this drug has led to a study throughout the US.

According to research results reported at the American Diabetes Association Convention this month (Diabetes, vol 49, supplement 1, abstract 306), metformin and placebo were tested on 82 children with confirmed diabetes between 10 and 18 years old. Fifty-seven of the participants were female, 30 white, 24 black, and 18 hispanic. At the beginning of the study, the average fasting blood sugar was 182 mg/dl and average HbA1c was 8.6%.

Forty-two received metformin and 40 received placebo in this randomized, double-blind, 16-week trial. The starting dose was 500 mg twice a day and increased to 1000 mg (max. adult dose is 2,500 mg.) over the next two weeks unless it was not tolerated.

At the end of the study, the fasting blood sugar had gone down an average of 43 mg/dl in the metformin group versus an average rise of 21 mg/dl in the placebo group. The HbA1c levels were significantly lowered to an average of 7.5% in the metformin group versus staying the same in the other group. Unfortunately, the drug had no effect on weight loss or cholesterol levels.

One person in the metformin group and two on placebo discontinued the study due to side effects, most commonly gastrointestinal. This is similar to the effects on adults who take metformin. This study suggests that metformin is an effective and safe diabetes treatment for children with Type 2 diabetes who are not managed by diet and exercise alone. 

Do People Really Take Their Prescriptions?

The United Kingdom Perspective Diabetes Study (UKPDS) recently concluded that people with Type 2 diabetes often need multiple oral diabetes medications to attain good blood glucose control. But will people with diabetes stick to their medications, especially when they are prescribed more than one? This question spurred the first population-based study on adherence to prescription medication.

The study included 2,920 citizens of Tayside, Scotland (Diabetes, vol 49, supplement 1, abstract 307) who have Type 2 and who were prescribed an oral diabetes drug between January of 1993 and December of 1995. These people were prescribed either sulfonylureas alone, metformin alone or the two together. Adherence was similar for the people taking single prescriptions (31% for sulfonylurea and 34 % for metformin). In contrast, participants receiving a combination of drugs kept to their prescription only 13% of the time. Adherence decreased for each increase in number of times a day a person was told to take their drug. Adherence also decreased with diabetes of longer duration, in people on other medications, and for socially deprived people.

The study indicates that sticking to prescribed medications is very poor, and may well explain the lack of benefit seen by clinicians who prescribe these medications. The greater number of drugs prescribed and the more often they are prescribed in a day, the less likely adherence becomes. If combination diabetes therapy is to succeed, new strategies to encourage people to take their medications will apparently be needed.

When To Add A Second Diabetes Drug

People with Type 2 diabetes on one of the sulfonylurea drugs often have to increase their dose over time to control their blood sugar. When the maximum dose no longer works, another diabetes drug that has a different method of acting on the body must be added, maybe even more than one.

An important question is when to add the second drug. Sulfonylurea drugs work by stimulating the beta cells of the pancreas to release more insulin to meet the challenge of high glucose levels. But over time the beta cells wear out and can not rise to the challenge as well. To avoid taking insulin, it is necessary to have the beta cells retain some function. The amount of beta cell function is measured by the c-peptide test.

A study was (Diabetes, vol 49, supplement 1, abstract 360) done to see if adding another diabetes drug from the class called troglitazones, which sensitize the body's cells to insulin, when the person is taking half the maximum dose of sulfonylurea would protect the beta cells from exhaustion. Troglitazone in 400 mg doses or placebo was given to 411 participants with Type 2 diabetes running high blood sugars greater than an Hb1c of 8%. Prior to troglitazone treatment, these people had been taking a half maximum (6 mg) dose of glyburide for 6 weeks, which they continued during the study. For 24 weeks, the participants received either placebo or troglitazone and were also given more glyburide if necessary for glycemic control.

At the end of the study, people receiving the placebo had had their glyburide increased to near maximum dose (12 mg), which had increased their C-peptide slightly but had had no effect on their blood sugar levels as measured by the HbA1c. Those given troglitazone needed less additional glyburide, their decreases in C-peptide levels were minimal, and their blood sugar control improved greatly. Sixty-five percent got their HbA1c below 8% and 31% below 7%.

Serious adverse, non-fatal events were the same for each group, but no adverse liver problems occurred. There were 5 deaths, all in the placebo group.

The results suggest that adding a glitazone when the person is on a half-maximum dose of sulfonylurea may spare beta-cell function and improve blood sugar control. Troglitazone (Rezulin) is no longer on the market, but Actos and Avandia work similarly and are expected to have the same effect.