Background:
Patients with type 1 diabetes (T1D) are at risk of severe, potentially hazardous, hypoglycemia. Changes in heart rate variability (HRV) patterns occur at the initiation of hypoglycemia due to sympathetic nervous system activity.
Objective:
We aimed to investigate the potential use of HRV- detection by a wearable device as an early alert for hypoglycemic events.
Methods:
Proof of principle study including 23 patients with T1D. Patients were asked to wear the VitalConnect HealthPatch onthe chest during five consecutive days. Hypoglycemic events were defined as glucose ≤3.9 mmol/l by finger stick measurement and verified by continuous glucose monitoring. Changes in HRV were retrospectively evaluated in standardized periods before a hypoglycemia was recorded.
Results:
66 hypoglycemic events were recorded by 23 patients (14 women, age 42± 11 years, diabetes duration 26±10 years).Hypoglycemia caused a clear detectable increase in LF:HF or decrease in RMSSD in 36 (55%) of the hypoglycemic events. Eighteen hypoglycemic events (27%) showed the opposite, i.e. a clear decrease in LF:HF and increase in RMSSD. Ten events (15%) contained insufficient data to determine changes in HRV. There were 2 events (3%) that did not display a change in either LF:HF or RMSSD.
Conclusion:
Hypoglycemic are preceded by changes in HRV that can be detected by a wearable device in patients with type 1 diabetes. Wearable devices measuring real time HRV seem promising devices for early detection of hypoglycemic events.