SAT152 Retrospective Analysis Of HbA1c In Patients Diagnosed With Pancreatic Insulinoma Prior To- And After Surgical Excision

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Abstract Disclosure: S.J. Lawless: None. A. McGrath: None. R. Campbell: None. D. O'Keeffe: None. M.J. Bell: None. Insulinomas are rare pancreatic tumours characterised by episodes of hyperinsulinaemic hypoglycaemia. Patients may develop secondary diabetes following surgical intervention for insulinoma. Glycated haemoglobin (HbA1c) is a reliable bio-marker for the diagnosis and prognosis of diabetes. HbA1c is a useful surrogate marker for insulinoma (1). A retrospective analysis of patients diagnosed with insulinoma and attending our service in Galway University Hospital (GUH) was performed. Data was collected using the electronic patient correspondence system to gather information from clinic letters, hospital and GP laboratory results were accessed on the Evolve laboratory system. Diagnostic criteria employed a 72-hour fast with plasma glucose levels of ≤2.2 mmol/L, with a corresponding insulin level ≥18 pmol/L and a c-peptide of <200 pmol/l. We analysed their HbA1c at initial presentation and longitudinally following treatment. There are currently six patients carrying a diagnosis of insulinoma attending our service. All of these patients have had surgical intervention. At diagnosis four of the six patients had a HbA1c taken. One patient was diagnosed prior to HbA1c being routinely available and another patient had initial investigations and management elsewhere. The average HbA1c at time of diagnosis was 27.75 mmol/mol (n=4) (reference range 20 to 42 mmol/mol). All insulinoma patients have their HbA1c monitored yearly as part of ongoing follow-up. HbA1c trends upwards with an average HbA1c 18-24 months post surgical excision of 36.25 mmol/mol (n=4). There is a tendency of increased HbA1c post-operatively with a mean increase in HbA1c of 8.5 mmol/mol over 18-24 months. Three of our six patients have developed diabetes on extended follow-up. The average time to diagnosis post-surgical resection was 5.5 years (n=3). HbA1c is a useful tool for monitoring for secondary diabetes post pancreatic surgery. While admitting our number of patients is low, it is interesting to observe the difference in HbA1c pre- and post-operatively in patients with insulinoma. 1.Vaidakis, Dennis, et al. "Pancreatic insulinoma: current issues and trends." Hepatobiliary & pancreatic diseases international: HBPD INT 9.3 (2010): 234-241. Presentation: Saturday, June 17, 2023