The Effect of Curative Treatment on Hyperglycemia in Patients With Cushing Syndrome.

CONTEXT: Hyperglycemia is a common complication of Cushing syndrome (CS). OBJECTIVE: We aimed to determine the impact of curative procedure on hyperglycemia and its management in patients with CS. METHODS: This retrospective longitudinal cohort study took place 2000 to 2019 in a referral center among adults with endogenous CS and hyperglycemia. Main outcome measures included glycated hemoglobin A1c (HbA1c), intensity of hyperglycemia therapy, and improvement of hyperglycemia. RESULTS: In 174 patients with CS (pituitary in 106, ectopic in 25, adrenal in 43), baseline median HbA1c was 6.9% (range, 4.9-13.1), with 41 (24%) patients not on any therapy for hyperglycemia, 93 (52%) on oral medications, and 64 (37%) on insulin (median daily units of 58; range, 10-360). Following CS remission, at the end of follow-up (median 10.5 months), 37 (21%) patients demonstrated resolution of hyperglycemia, 82 (47%) demonstrated improvement, and 55 (32%) had no change or worsening in hyperglycemia. At the end of follow-up, HbA1c decreased by 0.84% (P < .001) and daily insulin dose decreased by a mean of 30 units (P < .001). Biochemical hypercortisolism severity score (severe vs moderate/mild: odds ratio [OR] of 2.4 [95% CI, 1.1-4.9]), and CS subtype (nonadrenal vs adrenal: OR of 2.9 [95% CI, 1.3-6.4]), but not type of hyperglycemia (diabetes vs prediabetes: OR of 2.1 [0.9-4.9]) were associated with hyperglycemia improvement at the end of follow-up. CONCLUSION: Two-thirds of patients with CS and hyperglycemia demonstrate resolution or improvement of hyperglycemia after a curative procedure. Close monitoring during CS recovery is needed to ensure appropriate therapy modification.