A case of successful pioglitazone treatment of steroid diabetes due to Cushing syndrome

Steroid diabetes mellitus accompanies Cushing disease in 15–35% of cases. And in overwhelming majority of them its treatment represent a challenge even for experienced endocrinologist. Pioglitazone a thiazolidinedione (TZD) compound with peroxisome proliferators-activated receptor-γ (PPAR-γ) agonizing activity is potent insulin-sensitizing drug. TSDs have recently emerged as a potential therapy for Cushing disease. Our case represents another acknowledgement of the efficiency of such treatment. A 45 year old woman was admitted to our endocrinology center at Aug 2002 with symptoms of Cushing disease and steroid diabetes mellitus (HbA_1c –11,2%), two ulcers on the anterior surface of left shin during past 6 months. The combination of glibenclamide, metformin and diet was not able to control glycemia and ulcer epithelization. Insulin therapy was not seemed to be a priority as calculated doses of insulin for our patient in order to overcome the existing insulinresistance were high (Body Mass Index –34kg/m²). That is why our choice had fallen on pioglitazone that was prescribed at a dose 30mg/day. During treatment we observed high rate of the healing process –0,2 m²/day with complete healing in 8 weeks and improved glycemic control (Fasting Blood Glucose 6,2–7,8 mmol/l). Two months later proton radiotherapy was performed. By then we were able to observe noticeable redistribution of body fat from predominantly visceral into subcutaneous, FBG remained on the same level. After radiotherapy pioglitazone was substituted with glibenclamide (7mg/day) which within several next months had been gradually cancelled, despite of a residual activity of Cushing disease. Currently, diet alone is able to maintain HbA_1c at 6,0%, cortisol and ACTH rhythms are normal. Resume: pioglitazone might be the treatment of choice for glucocorticoid-induced diabetes mellitus due to Cushing disease.