Type 1 Diabetes at High Altitude: Performance of Personal Insulin Pumps and Patient Metabolic Control.

High-altitude trekking can expose people to extreme environmental conditions, like low temperatures and hypobaric hypoxia. Such extreme conditions make it more difficult for people with type 1 diabetes mellitus (T1DM) to maintain glycemic control. Intensive blood glucose monitoring using either glucose meters or continuous systems is imperative in these cases. In this observational study, we report metabolic control of T1DM patients and the performance of various insulin pumps at high altitude. All 19 patients with T1DM included in this study participated in the final step of the "5000 meters above sugar level" initiative, which involved trekking Damavand Mountain to an altitude of 5670 meters above sea level. We found that all pump models worked well without any disruption and no cases of diabetes decompensation or severe hypoglycemia occurred. Therefore, healthy, physically fit, and experienced individuals with T1DM should not be discouraged from participating in mountain trekking activities, as modern personal insulin pumps work well at high altitudes.