A wearable device that measures real-time heart rate variability can detect early signs of hypoglycemia in patients with type 1 diabetes, according to study results published in Diabetes Care.
To assess the ability of a wearable device to detect heart rate variability and alert users to early signs of hypoglycemia (glucose ≤70 mg/dL), researchers had 23 patients with type 1 diabetes (average age, 42 ± 11 years) wear the VitalConnect HealthPatch on their chests for 5 consecutive days.
While conducting their normal daily activities, participants were analyzed for heart rate variability. Participants also recorded fingerstick glucose measurements and any hypoglycemic events they experienced. There were 9 participants with impaired awareness of hypoglycemia, defined as having lost sense of typical hypoglycemia symptoms.
Overall, there were 66 hypoglycemic events, 22 of which were deemed to be serious. Average glucose level during hypoglycemia events was 56 mg/dL. In response to hypoglycemia, there were significant changes in heart rate variability measures of balance between parasympathetic and sympathetic tone; the average ratio between low and high frequency changes in heart rate variability increased by 0.2 (P <.05), and average square root of the mean standard differences of successive R-R intervals decreased by 4.4 (P <.05). Average standard deviation of the R-R intervals remained the same.
In 36 (55%) recorded hypoglycemic events, there was a clearly detectable increase in low-frequency/high-frequency ratio changes and/or a decrease in the square root of the mean standard differences of successive R-R intervals, meaning initiation of hypoglycemia caused a typical heart rate variability pattern. Of the remaining events, 18 (27%) showed an atypical heart rate variability pattern, 10 (15%) could not be classified, and 2 (3%) caused no change.
The researchers reported limited generalizability because of the small sample size and brief study duration.
“[T]his study shows that [heart rate variability changes] at the initiation of hypoglycemia can be detected by a wearable device,” the researchers said. “Considering developments in wearables and data analytics, measuring real-time [heart rate variability] seems promising for early detection of hypoglycemia in people with diabetes.”
Bekkink MO, Koeneman M, de Galan BE, Bredie SJ. Early detection of hypoglycemia in type 1 diabetes using heart rate variability measured by a wearable device. Diabetes Care. 2019;42(4):689-692.