ANTHROPOMETRIC FEATURES AND TUMOR SIZE DO NOT PREDICT DURATION OF FAST IN INSULINOMA

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 327-337-Neuroendocrine Tumors
Clinical
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-334
Diane Donegan*, Clive S. Grant, Geoffrey B Thompson, F John Service and Adrian Vella
Mayo Clinic, Rochester, MN
Anthropometric features and tumor size do not predict duration of fast in insulinoma

Donegan D1, Grant CS2, Thompson GB2, Service FJ3, Vella A3

1Department of General Internal Medicine, 2Department of Surgery, 3Department of Endocrinology and Metabolism, Mayo Clinic, Rochester, MN

Background:The 72 hour fast is utilized to provoke hypoglycemia, document Whipple’s triad and understand the mechanism of hypoglycemia. Although in more than half of all positive fasts, hypoglycemia develops within the first 24 hours, a significant percentage of subjects require inpatient admission to complete the fast.  Identifying possible determinants of fast duration may help to predict the need for admission.  

Aim:To determine the relation between anthropometric features, tumor size and B-cell polypeptide concentrations on the duration of the 72 hour fast in insulinoma.

Methods:A retrospective analysis of patients with insulinoma in the past 25 years who underwent a 72 hour fast conducted. A multivariate analysis examined the association of age, weight, gender, body mass index (BMI) and tumor size with duration of 72 hour fast. A secondary analysis was undertaken to examine the association, if any, with the concentration of β-cell polypeptides at the end of the fast.

Results:  239 patients underwent the 72 hour fast.  Of these 62% were female. The mean age at diagnosis was 51±15years with a BMI of 28.3±2 kg/m2. Duration of fast was documented in 185 patients and was not associated with gender (p=0.18), age (p=1), weight (p=0.1), BMI (p=0.11) or tumor volume (p=0.25).  A longer duration of a fast was inversely related to end of fast C-peptide (p=0.03) but not insulin (p= 0.51) or proinsulin (p>0.05) concentration. This association was however explained by BMI and age.

Conclusion: Duration of fast was not significantly related to anthropometric measurements including age, gender, weight, BMI or tumor volume. Consequently, the duration of fast cannot be predicted on the basis of clinical characteristics and provides no information on insulinoma size.

Nothing to Disclose: DD, CSG, GBT, FJS, AV

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