Canagliflozin Improves Obesity and Insulin Resistance in a Diabetic Patient with Cushings Disease Undergoing Postoperative Steroid Therapy: A Case Report

A 47-year-old woman with diabetes treated with high-dose insulin was admitted to Mie University Hospital, Tsu, Japan, for screening of secondary diabetes mellitus and obesity. Laboratory tests and imaging studies were consistent with Cushing's disease (CD). The patient underwent trans-sphenoidal pituitary surgery. The patient exhibited loss of body weight (85.9 to 80.0 kg), improved glycated hemoglobin (HbA1c) (11.2 to 7.8%) and required lower doses of insulin (112 to 46 U/day) 6 months after surgery. The patient's body weight and daily insulin dose remained stable during the following 5 months (6-11 months after surgery). At that point, the patient was administered with canagliflozin, a sodium-glucose cotransporter 2 inhibitor. The patient required lower daily insulin dose without decreasing the dose of postoperative hydrocortisone concurrent to the administration of canagliflozin (100 mg/day). The patient's body weight decreased to 69.5 kg and withdrawal of insulin therapy was possible 8 months after initiation of canagliflozin. Despite withdrawal of insulin therapy, the HbA1c levels remained at <7.0%. Although surgical treatment is the first-choice treatment for CD, obesity-related metabolic disorders including diabetes are frequent in CD patients following surgery. Canagliflozin may be an effective treatment to reduce body weight and improve insulin resistance following surgical treatment of CD.