Safety, Feasibility, and User Experience of Automated Insulin Delivery Systems During Hajj (Muslim Pilgrimage)

<b>Background/Objectives:</b> Performing Hajj, the annual Islamic pilgrimage to Mecca and one of the world's largest mass gatherings, involves considerable physical exertion in high temperatures and presents unique challenges for people with type 1 diabetes (PWT1D). We examined the feasibility, safety, and user experience of automated insulin delivery (AID) systems during Hajj. <b>Methods:</b> This mixed-methods study evaluated six PWT1D who used an AID pump (2 MiniMed 780G, 2 Medtrum, 1 OmniPod 5, and 1 Open-source AID) while performing Hajj in 2024-2025. Pump and CGM-derived metrics were compared across pre-Hajj, during Hajj, and post-Hajj periods. A structured survey captured participants' experiences, challenges, and recommendations for AID use during Hajj. <b>Results:</b> The average percent time in range (TIR) remained stable from pre- to during Hajj (54.98 to 54.18, <i>p</i> > 0.05) and significantly increased post-Hajj (62.62, <i>p</i> < 0.05). The percent time above range (TAR > 180) and Glycemia Risk Index significantly decreased from pre- to post-Hajj (28.34 to 26.28 and 50.3 to 19.3, respectively, both <i>p</i> < 0.05). The percent time below range (TBR) remained low (<1%) across the three periods with no incidence of acute diabetes-related complications. Participants emphasized increased confidence and peace of mind with AID use and reported challenges related to heat exposure, prolonged walking, and lack of awareness regarding diabetes technology among HCPs. <b>Conclusions:</b> The use of AID during Hajj appeared to be safe and effective for PWT1D in our study, maintaining stable glycemic control under physically demanding conditions. As the first study to evaluate AID use during Hajj, our findings call for larger studies to explore the integration of diabetes technology into Hajj care protocols and highlight the need for structured pre-Hajj education for PWT1D and HCPs.