Viv asked me to look into the Diabetes Sentry, a $500 FDA-approved non-invasive perspiration-based wristband glucometer intended for night wear by diabetics and oriented to catching nighttime lows and highs, so I am gathering links in this post. This technology has been in development for years and has always proven challenging to implement, the ideal end-deployment scenario being that diabetics could wear a non-invasive continuous-monitoring glucometer and that device would then feed adjustment data to an automated invasive (or implanted, eventually) insulin pump, establishing what would effectively be a replacement for the diabetic’s damaged organs.

Links:

University of Florida Clinical Trial, 2014. Clinical Evaluation of a Non-Invasive Hypoglycemia Detector in a Glycogen Storage Disease Population “The device often failed to detect hypoglycemic episodes in glycogen storage disease patients and the rate of false positive alarms was high.” 

Bummer.

Journal of Diabetes Science and Technology, September 2015. Hypo- and Hyperglycemic Alarms – Devices and Algorithms. Daniel Howsmon, BS and B. Wayne Bequette, PhD. 

Article includes noninvasive and invasive monitoring devices and concentrates on invasive continuous glucose monitoring technology as demonstrably most effective, noting an approximate 1-in-3 false positive rate over several noninvasive devices. I did not note if the article cites the UofF study linked above, whose results are in line with the studies of other, older noninvasive monitors cited. The article does note that trial users of earlier systems did not want to stop using them despite the rate of false positives and cites “quality of life,” presumably deriving from the better-safe-than-sorry thesis combined with the diabetic user’s response to the alarm, which would require awakening and testing prior to adjusting insulin dosages.

This is interesting from another perspective in that it is well established that a key to long term healthy adjustment to living with diabetes is frequency of testing. Presumably the false overnight alarms drive up frequency of testing and therefore increase the diabetic’s data set, resulting in better glucose control. This is a powerful argument in favor of the device.

Health Central, Will the Diabetes Sentry Prevent Hypos?, David Mendosa, November 2013. 

A consumer-oriented review in which the writer obtains an early review unit and enlists the help of an insulin-dependent diabetic friend to assess the device’s performance. Interestingly, the writer notes that the Diabetes Sentry does not use the infrared perspiration analysis that other similar devices such as the GlucoWatch did in the past, but rather uses changes in skin temperature and skin humidity to invoke its alert. Mendosa’s user reported both false positives and failed detection, in one case citing a low that reached 40 without triggering an alarm. The user also appeared to be primarily testing the device in daytime and active conditions, which is not necessarily our visualized use case. The article also notes that the Diabetes Sentry is the second to-market iteration of the device, the prior incarnation having been marketed as the Sleep Sentry apparently under the mistaken impression by the manufacturer that the device had recieved FDA approval, which it had not.

All together, I would say that while $500 seems expensive for a device whose primary benefit appears to be increasing randomized overnight blood-sugar testing and insulin dosage adjustment – a result which could be obtained by setting randomized alarms on one’s cell phone or digital information device such as an Apple Watch or other fitness band – if Viv remains inclined to this purchase after understanding the projected limitations of the device, I am in favor of the pirchase simply because it has the potential to increase overnight testing frequency.