For people with type 1 diabetes, there are limited evidence-based resources to support self-management when traveling across multiple time zones. Here, we compared glycemic control on insulin degludec versus glargine U100 as the basal insulin for adults using multiple daily injections (MDI) while traveling across multiple time zones.


This randomized crossover pilot study compared insulin degludec versus glargine U100 for adults with type 1 diabetes using MDI insulin during long-haul travel to and from Hawaii to New York. Insulin degludec was administered daily at the same time regardless of time zone, and glargine was administered per travel algorithm. Primary end point was the percentage of time in range (TIR) between 70 and 140 mg/dL during the initial 24 h after each direction of travel. Secondary end points included standard continuous glucose monitoring metrics, jet lag, fatigue, and sleep.


The study enrolled 25 participants (56% women, mean ± SD age of 35 ± 14.5 years, HbA1c of 7.4 ± 1.2% [57 ± 13.1 mmol/mol], and diabetes duration of 20.6 ± 15 years). There was no significant difference in glycemic outcomes between the two arms of the study, including TIR, hypoglycemia, or hyperglycemia. Neither group achieved >70% TIR 70–180 mg/dL during travel. Jet lag was greater on glargine U100 in eastward travel but not westward. Fatigue was greater after westward travel on glargine. Sleep was not significantly different between basal insulins.


In adults with type 1 diabetes using MDI of insulin and traveling across multiple time zones, glycemic outcomes were similar comparing insulin degludec and glargine U100.

W.C.B. and K.N.C. contributed equally to this study.

Clinical trial reg. no. NCT03668808, clinicaltrials.gov

This article contains supplementary material online at https://doi.org/10.2337/figshare.16776259.

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