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Devices may aid diabetics’ constant monitoring

Researchers are hoping that glucose monitors will replace hated finger lances as more comfortable and convenient means of testing blood sugar levels for diabetics.
Diabetic Casey Burkhalter rows during a practice of The Episcopal High School of Jacksonville rowing team in Jacksonville, Fla., on April 6.Oscar Sosa / Washington Post
/ Source: a href="" linktype="External" resizable="true" status="true" scrollbars="true">The Washington Post</a

When Casey Burkhalter, 12, was diagnosed with diabetes 2 1/2 years ago, her parents started waking up repeatedly at night to test her blood sugar, typical of the exhausting tasks many of the nation's 21 million diabetics go through to extend their lives.

But no more. For four months the Jacksonville, Fla., girl has been wearing an experimental gadget that provides a continuous reading of her blood sugar and wakes the family if it falls dangerously low. The Burkhalters can sleep now, confident that their youngest child will be alive when the sun comes up. "My parents -- it's just been a cinderblock off their backs, not having to get up at night," Casey said.

The technique she's helping test is called continuous glucose monitoring, and it's a goal researchers have chased for nearly 50 years. Now, they say, they can finally see the finish line. Sophisticated monitoring devices that promise diabetics a new measure of freedom are just coming to market and are expected to be widely available in the United States by late this summer.

The monitors aren't perfect yet -- they're not as accurate as blood tests, and they're slow to discern the rapid changes in blood sugar that can accompany activities such as exercise. At least for now, patients who wear them are urged to draw blood periodically for comparison. But researchers hope that within a year or two, the devices will allow diabetics to go for long stretches, possibly days, without using the hated finger lances that are the bane of their existence.

High hopes for new monitors
People who have used the monitors say that, despite the limitations, they work without much discomfort. More importantly, initial research suggests the devices could improve the control of blood sugar, a task at which diabetics do poorly on average. That would offer a new way to cut the nation's $100-billion-a-year bill from diabetes complications and reduce the suffering -- heart disease, stroke, amputations, blindness, impotence, kidney failure -- associated with the disease.

"I want to tell the world about this," said Leslie Burkhalter, Casey's mother and a jewelry saleswoman in Jacksonville. "It's going to add years to people's lives. All these things going on right now -- amputations, heart disease -- it's all going to be stopped."

Few doctors are ready to go that far yet, but they are paying attention. "The idea that there are devices that are marketable is a big breakthrough," said William V. Tamborlane, a diabetes researcher at Yale University.

The devices from different manufacturers resemble one another. A patch worn on the abdomen carries a tiny wire that pokes through the skin to measure glucose in cellular fluid. The patch hurts a bit going on but is comfortable afterward, patients say. The patch is worn for several days, wirelessly transmitting information to a receiver the size of a mobile phone, before it is replaced with a new one.

The Juvenile Diabetes Research Foundation, a principal advocacy group for people with the most serious form of diabetes, has gone into overdrive in recent months as its officers concluded that the new devices could represent a big improvement in care.

"I think this signals a new era where we can take diabetes by the horns and really start to control it aggressively," said Aaron J. Kowalski, the group's director of strategic research. "Diabetics have been waiting a long, long time for this."

With money raised from bake sales and diabetes marches across the country, the foundation is launching a series of independent studies designed to test manufacturer claims about the new devices and provide information on their worth. Among the big questions are how much they can cut rates of hospitalization, car accidents caused by drivers with low blood sugar and the many other problems attributable to diabetes.

The group is also pushing to mate the glucose sensors with insulin pumps, which have been on the market for years, to create automated systems that might be able to control diabetes for days with minimal intervention. That technique has been tested on a small scale recently at Yale University, and the creation of a commercial system was recently designated a priority by the Food and Drug Administration.

In fact, one manufacturer has already combined a glucose monitor and a pump into a single product that won approval from the FDA on April 13 and is going on sale now. Patients won't be able to activate the monitor portion until this summer, and the device isn't fully automatic yet -- it will require a patient to consult a glucose readout and make decisions about insulin use.

But the manufacturer, Medtronic Inc., is working on software to automate much of the decision-making. The resulting device could amount to an external, artificial pancreas that basically controls blood sugar on its own for days, with the exception that a patient would have to inform it of upcoming meals and exercise. "We're fairly close," said Alan O. Marcus, director of medical affairs for Medtronic's diabetes unit.

The body burns glucose, a simple sugar, the way a car burns gasoline. But the level in the blood must be tightly controlled to prevent short-term coma or long-term health damage. In a healthy body, the pancreas releases a hormone, insulin, to instruct tissues to absorb sugar from the blood. But this fundamental life process is broken in diabetics: Their bodies either don't make insulin or resist its effects.

Pervasive ailment
Diabetes is one of the nation's most pervasive ailments, afflicting 7 percent of the population and fully 10 percent of adults. One form of the disease is linked to weight, and the problem is growing as Americans get fatter.

Pills help some people, but many need injected insulin. Until now, the state of the art in controlling diabetes has been to prick the fingers repeatedly throughout the day, drawing blood into a test strip and placing it in a glucose sensor to calculate insulin doses and guide eating.

Researchers have been trying to develop continuous glucose monitors since the early 1960s, and the field is littered with false starts and over-hyped gadgets that failed, most recently a watchlike device that caused burns and rashes. But now, doctors say, companies are finally making monitors that work.

The first of the new devices, from Medtronic, won FDA approval last year, but the company has rolled it out slowly, selling it in only seven cities to date. Medtronic is working out kinks and, like other manufacturers, studying how to educate patients in complex new procedures.

A device from DexCom Inc. of San Diego won FDA approval late last month, and one from Abbott Laboratories of North Chicago, Ill., is on the FDA's desk for approval. Overall, three or four continuous monitors are expected to be available nationwide by late this summer.

The new monitors don't entirely eliminate the need for finger-sticks, at least not yet.

Each time the sensor patch is changed, every three to five days, the glucose monitor must be calibrated using blood tests. And for the moment, the FDA and manufacturers are urging patients to draw blood to confirm a gadget reading before adjusting their blood sugar. If people follow that advice, the main advantage of the gadgets will be to alert them when to test.

But already, it's clear patients are becoming more dependent on the devices than the official instructions recommend. After finding it accurate most of the time and figuring out when it's likely to be less accurate -- during hard exercise, for example -- they start relying on the gadget with few finger-sticks.

"I trust it almost completely," Casey Burkhalter said.

The manufacturers are conducting studies to show their products can replace finger-sticks most of the time, a set of claims the diabetes foundation plans to check with its own studies.

A looming question is whether insurance companies will pay for the gadgets, expected to run from $500 to $2,000, and for the $35-and-up sensor patches that must be changed every few days. Historically, insurers have resisted new diabetes technology until studies prove it can cut costs or reduce medical complications, and those aren't finished.

Matt Vogel, a San Francisco diabetic and triathlete, ordered a DexCom monitor two days after the FDA approved the device. He has been comparing it to blood tests and keeping an Internet journal. The biggest problem so far is a time lag in detecting low sugar after exercise. But the device has awakened him at night when his sugar fell dangerously low, and overall, he rates it highly -- "about 90 percent."

A big issue for diabetics, he said, will be adjusting overnight from too little glucose information to a surfeit of it.

"This isn't going to be like a cure or any sort of silver-bullet solution," he said. "It's going to take quite a bit more thinking and quite a bit more problem-solving in order to really take advantage of it."