Increased plasma β-hydroxybutyrate levels during the fasting test in patients with endogenous hyperinsulinaemic hypoglycaemia

Abstract

Objective: The objective of the present study was to determine whether a plasma b-hydroxybutyrate (BOHB) level >2700 mmol/l during the 72-h fasting test is sufficient to rule out the diagnosis of endogenous hyperinsulinaemic hypoglycaemia (EHH). Research design and methods: We retrospectively studied BOHB levels in 39 patients with EHH who had undergone a 72-h fasting test to make the diagnosis of EHH, and we compared EHH patients with BOHB levels <2700 mmol/l (group 1), EHH patients with BOHB levels >2700 μmol/l (group 2) and 59 controls (median glycaemia: 3.2 mmol/l and median BOHB: 6095 mmol/l). Results: During a 72-h fasting test, nine patients (group 1) had BOHB levels O2700 μmol/l (median 6140 and range 2957-7824) and 30 patients (group 2) had BOHB levels>2700 μmol/l (median 542 and range 0-2607). In group 1, four patients had undergone partial pancreatectomy previously and were evaluated for the recurrence of hypoglycaemia, whereas none of the group 2 patients had been operated. The duration of the fasting test was longer in group 1 than in group 2 (P=0.0001), and at the end of the fasting test, plasma glucose concentrations were not significantly different (PZ0.0617), but insulin (PZ0.004), C-peptide (PZ0.0015) and proinsulin (PZ0.0038) levels were significantly lower in group 1 patients than in group 2 patients, suggesting lower insulin secretion and/or impaired glycaemic counter-regulation. Conclusion: During a fasting test, a BOHB level >2700 μmol/l is observed in some EHH patients, suggesting that BOHB levels cannot rule out the recurrence of EHH, in particular, after partial pancreatectomy. © 2013 European Society of Endocrinology.