LB111 - FASTING BEFORE ELECTIVE ABDOMINAL ULTRASOUND: PERSISTENCE OF PROLONGED FASTING RECOMMENDATIONS DESPITE LIMITED EVIDENCE

LB111

FASTING BEFORE ELECTIVE ABDOMINAL ULTRASOUND: PERSISTENCE OF PROLONGED FASTING RECOMMENDATIONS DESPITE LIMITED EVIDENCE

T. Braasch^1,2,*, I. Hoffmann^3,4, A. Deckert⁵, O. Horstick⁵, B. Siegmund^2,6

¹Internal Medicine, Bundeswehrkrankenhaus Berlin, ²Gastroenterology, Infectious Diseases and Rheumatology, Charite - Universitaetsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, ³Bundeswehr Medical Care Center, Frankenberg, Germany, ⁴Injury Epidemiology and Prevention (IEP) Research Group, Turku University Hospital and University of Turku, Turku, Finland, ⁵Heidelberg Institute of Global Health (HIGH), Heidelberg University Hospital, Heidelberg, ⁶Cluster of Excellence ImmunoPreCept, Charite - Universitaetsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany

Rationale: Fasting before elective abdominal ultrasound is widely recommended despite limited supporting evidence and may unnecessarily burden nutritionally vulnerable patients.

Methods: We performed a systematic review and meta-analysis (PROSPERO CRD42024568514) of fasting versus non-fasting preparation before elective abdominal ultrasound in adults concerning diagnostic sufficiency and analyzed publicly accessible fasting recommendations from hospitals and ambulatory providers in the federal state of Berlin, Germany, as well as online search results, and AI-based chatbots.

Results: Fourteen studies involving 2,208 participants were included. In the primary meta-analysis of three randomized trials (n=378), fasting was not associated with improved overall diagnostic sufficiency (OR 0.97, 95% CI 0.51–1.86; I²=0%). Benefits were mainly limited to gallbladder and common bile duct visualization. Overall certainty of evidence was low (GRADE). Only 3/36 hospitals provided publicly accessible preparation instructions, differing widely. Among 21 ambulatory provider websites with explicit fasting recommendations, prolonged fasting (≥8 h or overnight) was most common (47.6%). Google search results and AI-based chatbots frequently recommended fasting periods of 6–8 hours despite limited supporting evidence. None of the reviewed online recommendations referenced supporting evidence or addressed malnutrition, frailty, or individualized fasting strategies for vulnerable patients.

Conclusion: Routine fasting before elective abdominal ultrasound remains common across healthcare providers and public online information sources despite limited evidence for improved overall diagnostic sufficiency. More evidence-based and patient-centered preparation protocols should be considered.

Disclosure of Interest: T. Braasch: None declared, I. Hoffmann: None declared, A. Deckert: None declared, O. Horstick: None declared, B. Siegmund Grant / Research Support from: Pfizer, Consultant for: AbbVie, Abivax, AltruBio, Boehringer Ingelheim, Bristol Myers Squibb, Dr. Falk Pharma, Endpoint Health, Eli Lilly, Galapagos, Janssen/ Johnson& Johnson, Materia Prima, MSD, Pfizer, Takeda, Wedbush Securities; , Speakers Bureau of: AbbVie, AlfaSigma, Bristol Myers Squibb, CED Service GmbH, Dr. Falk Pharma, Eli Lilly, Galapagos, MD Education, MSD, Janssen/Johnson&Johnson, Pfizer, Tr1xBio