Impact of the Addition of Beta-Hydroxybutyrate in the 72-Hour Fast Protocol on Hospitalization Duration: A Quality...

The 72-hour fast is the "gold standard" test for detecting insulinoma but imposes significant burdens on patients and expends hospital resources. Balancing diagnostic accuracy with patient comfort and cost remains challenging. We aimed to leverage the metabolic indicator beta-hydroxybutyrate (BHB), indicative of insulin suppression, to curtail inpatient fasting time without missing insulinoma cases.

Our institution implemented an inpatient 72-hour fast protocol in 2018, and updated the protocol in 2020 to include a BHB >2.7 mmol/L stopping criterion. In this quality improvement and patient safety project, we retrospectively reviewed all patients who completed a 72-hour fast at our institution by the original (January 2018 to June 2020) and updated (June 2020 to December 2022) protocols.

Sixty-four patients (78% female, mean age 48 ± 17 years) underwent fasting: 34 patients by the original protocol and 30 patients by the revised protocol. The original protocol had an average fast duration of 57.6 hours (median 72 hours, IQR [49,72]). After the update, 50% (N = 15) ended for BHB >2.7 mmol/L, with an average fast duration of 49.7 hours (median 53 hours, IQR [39.1, 71.8], P = .03). This reduced cumulative inpatient fasting by 376.5 hours and reduced medical costs. All insulinoma cases (N = 7) developed hypoglycemia within 43 hours with BHB ≤1.2 mmol/L; no cases were missed.

Adding a BHB >2.7 mmol/L stopping criterion reduced inpatient hospitalization time, medical costs, and patient burden without compromising insulinoma detection. This evidence-based intervention improves patient adherence and more effectively uses hospital resources.