Insulinoma With Secondary Adrenal Dysfunction: Clinical Characteristics and High-Risk Factors

The purpose of this study is to investigate the clinical characteristics and high-risk factors of insulinoma combined with secondary adrenal cortical dysfunction.

We conducted a retrospective study including 44 surgically confirmed insulinoma patients and 16 diabetes patients with hypoglycemia from 2010 to 2023. Serum cortisol was measured on non-hypoglycemic days at three time points (8 AM, 4 PM, and 0 AM), and ACTH was measured at 8 AM on non-hypoglycemic days. Tumour size was assessed by imaging and pathology. Significance for all analyses were determined at the p < 0.05. IBM SPSS Statistic 27 was used for statistical analysis.

Compared to type 2 diabetes patients with hypoglycemia, insulinoma patients had lower serum cortisol at three points (8 AM, 4 PM, 0 AM) and lower blood glucose levels during hypoglycemia. In insulinoma patient group, patients with insulin release index (IRI) > 1.2 and the insulin levels > 38.6 μIU/mL had larger tumour diameters compared to the patients with IRI < 0.3 and 18.8-38.6 μIU/mL, respectively. The tumour diameters ≥ 1 cm group had lower morning serum cortisol and ACTH compared to those with tumour diameters < 1 cm group. In insulinoma groups, the tumour diameter is negatively correlated with morning cortisol (r = -0.44, p = 0.013), positively correlated with insulin (r = 0.437, p = 0.014), and insulin release index (r = 0.506, p = 0.004).

Insulinoma patients with secondary adrenal dysfunction have a higher risk of severe hypoglycemia. Our study suggest a potential correlation between tumour size and secondary adrenal dysfunction in insulinoma patients which may increase perioperative risks. Routine screening for adrenal cortical function is recommended to prevent the occurrence of more serious complications.