What types of complications arise for individuals with diabetes during air travel across time zones?

During eastward travel, the passenger crosses several time zones, which creates issues related to the timing of doses of injectable insulin and hypoglycemic agents. Eastward travel leads to a shorter day. For example, London is five hours ahead of New York. So the traveler will adjust his or her watch five hours ahead and dose the insulin too early. This is especially problematic with shorter-acting basal insulin, where premature dosing can result in severe hypoglycemia. We think that the risks are lower with longer-acting agents, but there are no studies among airline passengers confirming this.

In Westward travel, the reverse is true. The passenger gains five hours. Passengers who set their watches to New York time will end up waiting five hours longer to take their insulin, which can result in hyperglycemia. This is especially problematic for people with Type 1 diabetes who are completely insulin dependent and are at greatest risk for diabetic ketoacidosis.

Based on your study, what recommendations do you have for individuals with diabetes who are traveling across time zones?

  • For short/rapid-acting insulin, no dose adjustment is recommended.
  • During eastward travel, intermediate/long-acting insulins should be reduced in dose proportional to hours lost.
  • During westward travel, correction scale insulin with rapid-acting insulin can be used, or the dose administered during travel can be given as divided doses to span the longer travel day.
  • Pre-mixed insulins are discouraged, due to difficulty in titration
  • Sulfonylureas and glinides should be held during eastward travel

Are there any special considerations that pertain specifically to insulin pumps?

Insulin pumps present a unique challenge. Although the usual basal bolus dosing does not need to be adjusted, caution needs to be exercised because cabin depressurization may lead to unintended bolus dosing, which can increase the risk of hypoglycemia. This was especially the case with older pumps, and the problem may apply to newer generation pumps as well.

The recommendation we found was to disconnect the pump prior to ascent and descent. Any visible bubbles that form during ascent should be removed prior to reconnecting the device upon reaching cruising altitude.