Practice Update: DIABETES

CONFERENCE COVERAGE 10

U500 insulin screening of diabetic patients uncovers large amount of undiagnosed hypercorticolismconsistent with Cushing’s syndrome

J oseph Wolfgang Mathews, MD, of Palmetto Endocrinology, Summerville, South Caro- lina, explained, “Studies screening patients with diabetes for hypercortisolism indicate that 2–10% of patients suffer from undiagnosed Cushing’s syndrome. These authors concluded that such a low percentage prevents screening of all diabetic patients Cush- ing’s syndrome. “The Centers for Disease Control and Prevention estimate that in 2014, 29.1 million Amer- icans suffered from diabetes. So we tried to identify a more at-risk population to screen those with severe insulin resistance requiring high doses of insulin.” Patients with type 2 diabetes requiring concentrated insulin (Humulin R U500, Lilly), how- ever, suffer severe insulin resistance and hyperglycemia that result from undiagnosed and uncontrolled hypercortisolism. This was the first report on screening patients for Cushing’s syndrome using U500 insulin. “U500 insulin is used commonly in patients who require more than 200 units of insulin daily,” Dr Mathews said. “Identifying patients with hypercortisolism is important,” Dr Mathews said, “but not easy. Patients can present a wide range of phenotypes with mild symptoms easily attributed to other conditions.” He continued, “Excess cortisol contributes to dysfunction in multiple organ systems includ- ing muscle weakness and atrophy, osteoporosis, dermatologic manifestations, menstrual irregularities, insomnia, mood disturbances, recurrent infection, obesity, hypertension, dyslipidemia, and insulin resistance. These metabolic disturbances increase the risk of heart attack, stroke, and death. So we wanted to determine the prevalence of hypercor- tisolism in our patient population.” “In our community endocrine practice,” Dr Mathews said, “we screened 34 patients using concentrated U500 insulin. Twenty-one patients (62%) had a biochemical indicator of hypercortisolism consistent with Cushing’s syndrome. Of those 21 patients, 13 underwent imaging at the time of publication, and nine showed radiologically confirmed hyperplasia or adenoma. The remaining patients are anticipated to complete imaging soon.” Dr Mathews concluded that in this community practice, 50% of patients screened by using concentrated U500 insulin were found to suffer from underlying hypercortisolism con- sistent with Cushing’s syndrome. These patients likely represent a population enriched in undiagnosed Cushing’s syndrome who would benefit from testing and treatment.

Fifty percent of patients screened using concentrated U500 insulin were found to suffer from underlying hypercortisolism consistent with Cushing’s syndrome, reports a community-based, randomized screening study.

It would make sense to consider screening patients requiring U500 insulin for Cushing’s syndrome. Once such patients are identified, they can receive more targeted therapy to improve their morbidity and mortality.

“Results of our study,” he added, “demon- strated that hypercortisolism appears to be prevalent in the population of patients requiring concentrated U500 insulin. The majority of these patients appear to have an adrenal etiology of hypercortisolism.” He continued, “Based on this data, it would make sense to consider screen- ing patients requiring U500 insulin for Cushing’s syndrome. Once such patients are identified, they can receive more tar- geted therapy to improve their morbidity and mortality.” Paras Mehta, MD, of Baylor College of Medicine, Houston, Texas, highlighted the difficulty of diagnosing and manag- ing Cushing’s syndrome in a case series. Individualized treatment of Cushing’s syndrome He explained that while the diagnosis of Cushing’s syndrome is often une- quivocal, determining its etiology and managing the syndrome effectively remain a challenge.

© Photo by Jean Whiteside/AACE 2017

PRACTICEUPDATE DIABETES