Background: Hyperglycemia or diabetes is a well-known side effect of treatment with glucocorticoids. In patients with brain tumors, glucocorticoids are widely used to treat symptoms of peritumoral edema. We conducted a retrospective study of patients with suspected brain tumor to determine the incidence of and risk factors for glucocorticoid-induced diabetes.

Methods: This was a retrospective study of patients referred with suspected brain tumor to a neurological department, using data from a clinical database, electronic medical records, the laboratory system, and the pathology information bank. . Nondiabetic patients with a neuroimaging-verified brain tumor treated with high-dose glucocorticoid and monitored with glucose measurements were included in the study.

Results: Among 809 patients referred with suspected brain tumor, 171 were eligible for the study. Thirty-eight (22%) patients developed glucocorticoid-induced diabetes, defined as 2 glucose measurements ≥200 mg/dl (11.1 mmol/l) within the first week of treatment, and 4 of the patients were treated with insulin. The majority of patients with glucocorticoid-induced diabetes were identified on days 2, 3, and 4, and glucose levels were highest in the afternoon and evening. We were not able to identify any risk factors for glucocorticoid-induced diabetes and glucocorticoid-induced diabetes had no influence on survival in our cohort.

Conclusions: Glucocorticoid-induced diabetes is frequent in the first 7 days of treatment in patients with brain tumors. The results emphasize the need for screening for glucocorticoid-induced diabetes in this group of patients to avoid comorbidity expected to arise from hyperglycemia.