BLOG: Daylight saving time and the artificial pancreas
The New England Journal of Medicine recently published a breakthrough study on the so-called artificial pancreas.
This technological innovation carries a great and long-awaited promise for people with type 1 diabetes, who have completely lost the insulin-secreting function of the beta-cells of the pancreas. It has been established that the best insulin delivery system for people with type 1 diabetes is continuous subcutaneous insulin infusion, also known as an insulin pump.
The idea behind the insulin pump mechanism is that the pump delivers basal insulin continuously infused under the skin at a rate that may vary during different periods at night or during the day. For example, when we are asleep, the body’s insulin requirement may decrease because most of the food eaten in the evening will get absorbed and consumed in few hours. Similarly, when we are more physically active at certain times during the day, the insulin requirements may also decrease. The pump also delivers bolus insulin doses to cover the insulin requirements for meals as well as to correct for high glucose. Likewise, these bolus doses depend on the time of the day.
When the insulin pump is supplemented with a continuous glucose monitor, this improvised technology can come closer to mimicking the physiological function of the pancreas. The ultimate quest has been the realization of the fully operational closed-loop system, “the artificial pancreas,” where the patient does not have to do anything with respect to insulin dosing or glucose checks.
That is, the artificial pancreas learns to deliver insulin (basal and bolus dosing) automatically.
During the past two decades, we have been continuously promised by scientists in the engineering community that the “artificial pancreas is around the corner.”
So, whenever a new advance in the technology is announced, we always ask: Are we there yet?
Well, we are not there yet, but we are close!
The latest technologic advance has been the hybrid, semi-closed loop, in which the pump has been providing the basal insulin dosing, but the patient still has to do the bolus calculation and dosing, as well as calibrating the sensor with glucose fingersticks.
Now, we have this landmark study by Brown and colleagues, which proved for the first time that a closed-loop automated insulin pump is possible, in a carefully designed study in carefully selected patients.
The study is very promising. However, this study has limitations. Daniela Bruttomesso, MD, from the department of medicine at the University of Padua in Italy, who wrote the associated editorial, highlighted these limitations, stating, “We are not there yet, but the trial by Brown et al. offers an almost fingerstick-free operation, providing a big step toward a brighter future for patients.”
This news is coinciding with the daylight saving time change. What does this have to do with the artificial pancreas?
Since we are not there yet with a fully automated insulin delivery system, we must rely on current insulin pumps that our patients are using. These pumps still suffer from some technical glitches that can be potentially harmful.
Every spring and fall, around the time of the DST change, I remind people with diabetes who use insulin pumps and their clinicians that currently available insulin pumps do not adjust time settings automatically. Clocks must be adjusted manually at the time of the DST change, as well as when travelling across time zones. Clocks must also be manually adjusted when starting the pump for the first time, changing pump batteries, or at any time the pump is restarted for any technical reasons.
Correct insulin dosing is contingent on correct synching of the pump’s clock with the ambient time.
As important, the a.m./p.m. time setting should never be flipped; then all insulin dosing settings will be reversed between night and day, as I have explained in a prior post.
This fall, the DST change will occur on Sunday, November 3. Devices that need manual adjustment should be adjusted around midnight of that weekend’s Saturday/Sunday transition.
Reference: Brown SA, et al. N Engl J Med. 2019; doi:10.1056/NEJMoa1907863.