Want to make a billion dollars? Here’s a hot tip: Invent wearable technology that detects diabetes, measures glucose levels, and determines how much insulin is needed – all without the need for a single drop of blood.

If you accept this mission, there’s a catch: You’ll have a whole bunch of company. When it comes to using technology to free patients with diabetes from the dreaded finger stick, “hope springs eternal in the hearts of scientists, entrepreneurs, opportunists, and charlatans alike,” writes electrochemical specialist and consultant John L. Smith, PhD, in his book “ The Pursuit of Noninvasive Glucose .”

Google and Apple have been in the hunt, along with countless makers of devices and software. A noninvasive glucose monitoring system is the prime target, but there’s also plenty of interest in software that puts data from such devices as heartbeat sensors to work.

“Patients with diabetes are likely to be the early winners in the rise of digital health, a sector that attracted investment of $4.7 billion in 2017,” said Laura Baers, PhD , a technology adviser with the market research company IDTechEx, in an interview.

For the moment, however, results are elusive, and the name of the game is hype.

Early failure has a lasting impact

In the beginning, there was Glucowatch. And it was not good.

The GlucoWatch G2 Biographer product received approval from the Food and Drug Administration back in 2001 and touted as a high-tech tool to monitor glucose levels via interstitial concentrations every 10 minutes. The device promised to draw glucose to the skin surface for measurement via electric shocks, and alarms were to go off when hypoglycemia or hyperglycemia was detected.

But numerous problems cropped up. There was a time lag, with the device estimating glucose levels that actually occurred 15-20 minutes earlier. Some patients couldn’t tolerate wearing the watch, and some were burned by the electric current.

And perhaps worst of all, the measurements often weren’t accurate, with one study finding that more than half of 240 nighttime alarms incorrectly warned children with diabetes of dangerously high or low glucose. ( Diabetes Technol Ther. 2005 June; 7[3]:440-7 ).

As a result of the Glucowatch debacle, the FDA “become a little gun shy about approving anything. It made it even harder to approve something,” said Mark J. Rice, MD, of Vanderbilt University, Nashville, Tenn., who has tried to develop glucose-measuring technology.

Glucowatch was removed from the market, and no noninvasive glucose-monitoring devices are currently being sold in the United States. That leaves plenty of room for the companies that want a piece of the action.

“If a device were to be commercialized, it would be hugely disruptive to the industry,” according to Dr. Baers, who said that she expects a device eventually will lead to higher levels of diabetes control and fewer side effects. “This would result in billion-dollar savings for the health care industry and reduced complications,” she said.

On tech front, promises and more promises

So far, there have been more promises than actual products.

If you don’t look too closely at the website of a device called GlucoWise , you might assume a noninvasive glucose monitor already exists. Under a photo of a smiling woman, the site promises a “100% pain-free device that makes traditional blood sampling a thing of the past.”

The “simple yet highly reliable” device, which looks a bit like a large clip for a potato chip bag, promises to measure glucose through high-frequency radio waves that penetrate thin body tissue in the earlobe or the area between the thumb and forefinger.

But the GlucoWise device is neither approved nor available, and the company’s predictions that it would take preorders by late 2016 didn’t come true.

Another product called SugarBEAT missed its planned 2016 release and now hopes to be available in the Britain later this year. It promises to measure glucose levels every 5 minutes via a small disposable patch that draws interstitial fluid from the skin.

Meanwhile, Apple has enlisted biomedical engineers to work on a secret project to measure glucose continuously and noninvasively, CNBC reported last year. And Google announced in 2014 that it was working on a glucose-detecting contact lens that could alert patients via tiny LED lights – yes, apparently in the lenses themselves – if levels go too high or low. But neither of these technologies is ready for prime time.

Sneaky glucose molecules elude scientists

According to Dr. Rice, no truly noninvasive glucose-measuring technique has worked so far.

The challenge, he said, is that it’s difficult to measure tiny glucose molecules, which have no color and share many characteristics with H2O.

“The real problem is trying to measure a colorless molecule in a sea of water,” Dr. Rice said.

Glucose lab tests rely on indicators from reactions with other substances, he said, “but you can’t do that in the body.” Measuring glucose in tears or urine is one possibility, he said, but the scarcity in those liquids poses a challenge: “Your body doesn’t want to spill glucose and lose energy.”

Dr. Rice himself explored a glucose-measuring technique that aimed to correlate glucose levels to the speed of the retina’s reaction to light. The idea was that patients would wear special glasses that would shine a light in the eye at the press of a button. The project ultimately failed.

There are other challenges, said Dr. Baers, the technology adviser. “Glucose concentrations in sweat or tears are not reflective of blood glucose concentrations. To make things even more challenging, glucose levels in these fluids are orders of magnitude smaller than that found in blood.”

And, she said, there’s a time lag between glucose levels in blood and in other body fluids. “This means that a sweat glucose level is really giving information from an hour previous, which can be dangerous if you’re operating machinery or driving.”

Wearable diabetes tech targets more than glucose

There’s more to wearable, noninvasive diabetes technology than glucose-monitoring. One of the new frontiers is diagnostics.

Earlier this year, researchers from the University of California at San Francisco and the digital startup Cardiogram reported that they were able to use data from digital heart rate sensors (like those found in Apple Watches, Fitbits and other devices) to correctly detect diabetes in patients.

In a study presented at the 2018 meeting of the Association for the Advancement of Artificial Intelligence, the researchers said they detected diabetes in 85% of 462 participants (out of a pool of 14,011) who’d previously been diagnosed with the condition ( AAAAI abstract arXiv:1802.02511v1 [cs.LG] ).

Heart rates can offer insight into diabetes because “your pancreas is linked to your heart through both the sympathetic and parasympathetic nervous system,” said Cardiogram cofounder Brandon Ballinger in an interview. He pointed to a 2005 study that linked cardiac autonomic impairment to the development of diabetes. ( Diabetes Care 2005 Mar; 28[3]: 668-74 )

The next step is to test whether the data analysis can detect undiagnosed diabetes, Mr. Ballinger said.

As tech advances, questions remain

San Diego’s Scripps Whittier Diabetes Institute is another player in the diabetes/digital health world. It’s currently working on several clinical trials of diabetes technology, including a study into whether older adults with type 1 diabetes will benefit from a continuous glucose monitoring device with a wireless connection.

But Athena Philis-Tsimikas, MD, a corporate vice president with the institute, cautioned that wearable technology in diabetes is no cure-all. “Wearables and apps are never as easy as those who are selling them makes them sound,” she said. “They’re always more complex than the engineers that design them feel they are. And who has enough time to train them [patients] and fix the glitches?”

Devices that measure glucose can also suffer from errors in transmission, she said. And the existing continuous glucose monitors have trouble with accuracy at the very highest and lowest glucose levels, she said, although they are improving.

There are other questions about future wearable technology for diabetes: Will the devices cost more than continuous glucose monitoring systems (CGM), which are already pricey? How will private health information be protected? (As Mr. Ballinger noted, “wearable data itself is out of the scope of HIPAA.”) And will patients actually take action when their devices diagnose diabetes or warn them that their glucose levels are out of whack?

CGM systems provide insight into the latter issue. Repeated alarms about highs and lows can drive patients crazy, Dr. Philis-Tsimikas said. “You might end up with alarm fatigue and annoyance. They might hit a 250, but they won’t want the alarm to go off, and they don’t want to be reminded of it,” she said. “And they might go down to 60-80 at night, but they don’t want to be woken up because they’re used to that range.”

Even if patients do pay attention to their diabetes devices, they may not take the proper action. Dr. Philis-Tsimikas pointed to a 2016 study that found adding an exercise-tracking device to traditional weight-loss intervention didn’t lead to more weight loss. In fact, those who used the device actually loss less weight. ( JAMA. 2016;316[11]:1161-71 )

The lesson? “There has to be a combination of some education together with the physiologic information,” she said. For now, the good news is that “we still have other options,” Dr. Philis-Tsimikas said. The newly released CGM system known as the Freestyle Libre , she said, is one alternative.

And she mentioned another technique that’s still around. You could call it Old Faithful: the low-tech, high-hassle but highly accurate finger stick.

Dr. Baers and Dr. Rice report no disclosures. Dr. Philis-Tsimikas has no disclosures but notes that Scripps Whittier Diabetes Institute receives grants and funding in the diabetes field and works with a number of drug makers and device makers. Mr. Ballinger discloses salary and equity from Cardiogram.



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