Introduction: Arginine vasopressin deficiency (AVP-D) is characterized by impaired antidiuretic hormone secretion, leading to polyuria and a significant dehydration risk. The British Islamic Medical Association classifies AVP-D as a “very high risk” condition, advising against Ramadan fasting. However, many patients fast due to religious convictions, creating a gap between clinical guidelines and patient practice. This study evaluates the clinical outcomes and safety of fasting in this population. Methodology: A single-centre retrospective cohort study was conducted at Hospital Putrajaya. We included adults with permanent AVP-D on desmopressin therapy for more than 1 year who fasted during Ramadan 2025. Data were extracted from electronic medical records and patient consultations. Primary outcomes included hospitalization rates, dehydration symptoms, and desmopressin dose adjustments. Results: Of the 43 patients (mean age 42.4 ± 15.28 years; 53.5% female), 27 successfully fasted for a mean of 27.6 ± 6.56 days. Pre-Ramadan counseling was documented in only 55.8% of cases. While 25.9% of participants experienced dehydration symptoms (thirst, dizziness), and 22.2% broke their fast for safety reasons, there were no hospitalizations. None of the patients required additional desmopressin dose adjustments. Most patients (66.7%) maintained twicedaily desmopressin dosing (Sahur and Iftar). Anterior pituitary deficiencies were present in 70.3% of the cohort. Conclusion Despite being classified as very high risk, many AVP-D patients safely complete Ramadan fasting without severe adverse events. However, the high rate of dehydration symptoms and the significant gap in pre-Ramadan counseling (44.2% un-counseled) highlight the need for structured clinical reviews 4–6 weeks prior to Ramadan to optimize hydration and dosing
Humans ; Diabetes Insipidus, Neurogenic ; Retrospective Studies ; Arginine ; Fasting