According to the scientists who tested the new monitor, a wearable medical patch measuring the beat-to-beat deviation in heart rate could be a potential device for the early detection of hypoglycemia, or low blood sugar, in type 1 diabetes.
Results of their introductory research will be presented at ENDO 2018, the Endocrine Society’s 100th annual meeting in Chicago.
Hypoglycemia is common in adults with type 1 diabetes and in children. Left untreated, severe hypoglycemia can result in loss of consciousness, seizures, or even death. Sometimes people with diabetes do not distinguish symptoms of low blood sugar, a problem known as impaired awareness of hypoglycemia. Although wearing a constant glucose meter can aid in identifying hypoglycemia, the glucose sensor, inserted under the skin, usually has a delay.
“This delay can compromise the accuracy of measuring low glucose valuesPeople with impaired awareness of hypoglycemia may need to wear an additional monitor.
Marleen Olde Bekkink, Endocrinology Fellow, Radboud University Medical Center
Previous research learned that hypoglycemia accelerates one’s heart rate and modifies heart rate variability, which is the normal beat-to-beat deviation in heartbeats. Olde Bekkink and her colleagues tested the viability of detecting hypoglycemia using a commercially available biosensor called the HealthPatch (from VitalConnect, San Jose, Calif.) that measures heart rate and a single-lead electrocardiogram (ECG). The patch uninterruptedly measured the heart rate of 27 men and women with type 1 diabetes and self-reported recurrent impaired awareness of hypoglycemia. All the study subjects wore the adhesive patch on their chest, as well as a continuous glucose meter, for five days at home. In a diary, they noted down any low blood sugar level (lower than 70 milligrams per deciliter), confirmed by fingerstick measurement.
Wireless technology conveyed the heart rate data to a mobile Apple device, either an iPod or an iPhone. Then the researchers used an algorithm they formulated to define several parameters of heart rate variability. They conducted their major analysis on 39 hypoglycemic events that transpired in 10 subjects.
In 28, or 72%, of the low blood sugar events, the algorithm detected vivid patterns of change in heart rate deviation at the start of hypoglycemia, Olde Bekkink stated. She said these variations correspond with what happens at the start of low blood sugar: a stimulated sympathetic nervous system and suppressed activity of the parasympathetic nervous system.
Timely detection of impending hypoglycemia is critical to avoid severe, potentially life-threatening hypoglycemia. Our proof-of-principle study found that measuring heart rate variability using a wearable device in an outpatient setting seems promising for alerting to upcoming hypoglycemia.
Marleen Olde Bekkink, Endocrinology Fellow, Radboud University Medical Center
Since 11 hypoglycemic events showed no detectable variations, Olde Bekkink said they must further improve the algorithm to boost its accuracy and precision before being able to use the biosensor in everyday practice for patients with type 1 diabetes. Then the researchers would covert the data into an audiovisual hypoglycemia alert transmitted to a mobile device, she explained.
This research was funded by the Dutch Diabetes Research Fund in Amersfoort, Netherlands, and from Radboud University Medical Center’s innovation fund.