“If I’ve had low blood sugar during the night, most of the next day is a write-off,” says Gareth Woodward. Like more than 200,000 people in the UK, 27-year-old Woodward has type 1 diabetes, where the patient’s immune system attacks the cells that make insulin. He must take regular insulin to manage his condition. If he takes too much, though, his blood sugar levels can fall, resulting in hypoglycemia, commonly known as a “hypo”. Woodward has hypos during the night up to twice a week, and about once a year, he will have severe hypoglycemia, meaning he requires help from someone else. A few of these have also ocurred at night.
“I might notice him fidgeting, almost jumping around, and he’ll feel sweaty,” says his wife, Hannah. “I’ll try to wake him and if he doesn’t respond, I know he’s hypo. There have been times when I’ve had to call paramedics. It’s quite frightening.”
Nights can be a particular worry if you have diabetes, but controlling blood glucose levels with insulin injections is a balancing act at any time of day. It requires constantly estimating dosage, largely based on carbohydrate intake and expenditure. No one wants a hypo, but high blood sugar is to be avoided too, because it can cause serious complications such as cardiovascular disease and kidney problems. Now, a new blood glucose monitoring device aims to make striking a balance much easier.
The majority of people with type 1 diabetes in the UK test their blood around five times a day by pricking their finger and squeezing a drop on to a testing strip. The problem with that, says Pratik Choudhary, senior lecturer and consultant in diabetes at King’s College hospital in London, is that you never know what has happened between those tests. A new gadget, called the FreeStyle Libre, provides an instant way to check glucose levels, as well as showing whether blood sugar is rising or falling. A small plastic sensor, replaced fortnightly, is stuck to the upper arm, with a tiny probe puncturing the skin. A handheld reader displays the data when it is flashed over the sensor (you don’t even need to remove clothing). As well as giving instant readings, it can log what has been going on overnight and produce graphs showing long-term data. This can help users to identify patterns of highs and lows and adjust their diabetes care accordingly.
Mike Kendall, who was given the device to try, wrote on his blog everydayupsanddowns.co.uk: “For the first time ever, I have a full picture of what has been going on overnight, every single morning. And if I wake up blearily overnight I am FAR more likely to swipe the Libre than I am to get up and test.” You don’t even need to turn the light on, he points out. Concerned partners or parents could easily swipe, too, during the night (although the Libre isn’t yet licensed for use on children).
Many people, says Choudhary, “are really scared about nighttime hypos, so they err on the side of caution and compensate by underdosing with their insulin, resulting in high blood sugar.” There are many reasons why you might wake up feeling groggy or with a headache, but if you have type 1 diabetes, you tend to assume it is the cause. A patient of Choudhary, who is using the Libre, told him that he had woken up with a headache and thought: “Oh God, did I have a hypo last night?” But then he swiped the reader and found he hadn’t. The impact of worries about blood glucose levels is hard to measure, says Choudhary. “It varies from person to person, so we don’t put this into our NHS healthcare costings, but when you’re dealing with patients daily you realise the importance of it.”
For Jen Grieves, who writes the diabetes blog Young, Fun and Type 1, the key benefit was the ease of testing her glucose levels, “on the tube, train, running out of the door, walking down the street. I was testing 30 times a day.” The data out there is pretty clear, says Choudhary, “that the more you test, the better control you’ve got.” Seventy per cent of people with type 1 diabetes, he says, don’t have what is classed as “good control”.
The Libre isn’t the first device that can give such detailed, instant information, but it is the cheapest, simplest and least obtrusive. Continuous glucose monitoring (CGM) products have been around since 2001, but very few people in the UK with type 1 diabetes are able to get one on the NHS or can afford to buy one for themselves – they cost around £2,500 a year to run. The Libre costs about half that, although there’s an initial layout of £159.95 for the reader and first two sensors.
CGM devices do have an alarm function, which the Libre doesn’t, and so, theoretically, offer more protection at night. But, says Choudhary: “One paper says that people slept through 70% of the alarms.” There is also one device on the market, Medtronic’s VEO system, which works alongside an insulin pump attached to the abdomen, and delivers insulin more slowly than injections and has been shown to reduce the duration of nocturnal hypos. “If it alarms and you don’t wake up, it cuts the insulin dose automatically,” says Choudhary. However, this device costs a further £2.5k a year.
The holy grail of diabetes care is the artificial pancreas, which constantly monitors blood glucose and controls insulin automatically. This could be commercially viable in five years - but it will probably cost more than £7,000 a year per patient. As Choudhary points out, we’ve actually had pumps for 30 years and still only 10% of people use them in the UK. While the National Institute for Health and Care Excellence won’t be considering the Libre for NHS usage until clinical trials have concluded in June 2015, if it is approved it could make the blood-glucose balancing act much easier for thousands of people with type 1 diabetes.
