This article is more than 5 years old. Information may no longer be current.
Artificial pancreas informed by heart rate may reduce hypoglycemia risk during exercise
In patients with type 1 diabetes, an artificial pancreas closed-loop system that includes a heart rate signal may confer additional protection against hypoglycemia both during and immediately after exercise, according to recent findings.
In the clinical trial, researchers evaluated 12 patients with type 1 diabetes who were enrolled in a randomized crossover study at the University of Virginia Clinical Research Unit. The patients (median age, 38 years) had a glycated hemoglobin level of 6.9±0.2% and had type 1 diabetes for 23.6±4.4 years. The study participants were randomly allocated to a control-to-range (CTR) artificial pancreas system hospital admission, or a CTR system plus heart rate (HR) information (CTR+HR). The admissions were up to 26 hours in duration and entailed a mild bout of afternoon exercise.
The patients were instructed in the use of the DiAs portable artificial pancreas platform, which ran on an Android (Google, Mountainview, Calif.) smartphone and was programmed with the CTR and CTR +HR algorithms.
The plasma glucose of the participants was measured at least every 30 minutes using a model YSI 2300/2700 from Yellow Springs Instruments (Yellow Springs, Ohio). Hypoglycemia was defined as YSI reading below 70 mg/dL or appearance of hypoglycemic symptoms.
The researchers assessed low blood glucose (BG) index (LGBI), number of hypoglycemic events and overall control of glucose.
They found that the addition of HR to the CTR system significantly decreased the BG decrease during exercise (P=.022), yielded a slightly lower LGBI (P=.03) and led to fewer hypoglycemic incidence during the bout of exercise (zero vs. two events, P=.16). Additionally, the CT+HR algorithm resulted in an overall higher amount of time in the target range (81% vs. 75%, P=.2).
According to the researchers, these findings would need to be confirmed in patients with heart conditions, those with significant cardiovascular conditions, and at various levels of exercise intensity. Nonetheless, they acknowledged that the results show promise for adding heart rate to an artificial pancreas algorithm.
“HR has been used for the first time to inform the AP system, slowing the rate of glycemic decline associated with exercise, and possibly indicating a reduced risk and improved protection against hypoglycemia during and after exercise,” the researchers wrote.
Disclosure: Please see the full study for a list of relevant disclosures.