What is the utility of blood beta-hydroxybutyrate measurements in emergency department in patients without diabetes: a systematic review

BACKGROUND: Ketones are synthesised as an alternative fuel source during times of energy restriction. In the absence of a hyperglycemic emergency, ketosis in patients presenting to the emergency department (ED) may indicate reduced carbohydrate intake. In the perioperative setting, excess fasting with ketosis is associated with worse outcomes; however, whether ketosis in patients without diabetes presenting to ED is also associated with worse outcomes is unclear. This systematic review aims to examine the evidence for ketosis in predicting the need for hospital admission in patients without diabetes, presenting to the ED. METHODS: A systematic review was performed using PRISMA guidelines. We searched electronic bases (OVID-Medline, OVID-EMBASE, Scopus and PubMed) up to December 2022. Eligible studies included children or adults without diabetes presenting to the ED where a point-of-care capillary beta-hydroxybutyrate (BHB) was measured and compared to outcomes including the need for admission. Outcome measures included need for admission and length of stay. Content analysis was performed systematically; bias and certainty assessed using standard tools. RESULTS: The literature search found 17,133 citations, 14,965 papers were subjected to title and abstract screening. The full text of 62 eligible studies were reviewed. Seven articles met the inclusion criteria. Six studies were conducted solely in the paediatric population, and of these, four were limited to children presenting with gastroenteritis symptoms. Median BHB was higher in children requiring hospital admission with an AUC of 0.64–0.65 across two studies. There was a weak correlation between BHB and dehydration score or duration of symptoms. The single study in adults, limited to stroke presentations, observed no relationship between BHB and neurological deficit at presentation. All studies were at risk of bias using the Newcastle-Ottawa Scale and was assessed of “very low” to “low” quality due to their study design in the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Heterogeneity amongst selected studies precluded meta-analysis. CONCLUSION: The evidence for any utility of BHB measurement in the ED in absence of diabetes is limited to the paediatric population, specifically children presenting with symptoms of gastroenteritis. Any role in adults remains unexplored. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13643-023-02203-7.