This article is more than 5 years old. Information may no longer be current.

Nonfunctional adrenal tumors associated with increased risk of diabetes

Patients with nonfunctional adrenal tumors are at a higher risk for incident diabetes than individuals without adrenal tumors, according to findings published in the Annals of Internal Medicine.

The risk increase may result from glucocorticoid levels "considered normal by accepted standards," Diana Lopez, MD, from the division of endocrinology, diabetes, and hypertension at Brigham and Women's Hospital, and colleagues wrote.

"An estimated 10% of adrenocortical tumors may secrete excess cortisol without the classic signs or symptoms of Cushing syndrome, a phenomenon known as subclinical hypercortisolism," the researchers wrote. "Subclinical hypercortisolism has been associated with hypertension, insulin resistance, type 2 diabetes, hyperlipidemia, osteoporosis, and obesity, and recent studies suggest that it may increase the risk for incident cardiovascular events and death compared with nonfunctional adrenal tumors (NFATs). Therefore, screening for hypercortisolism is recommended for all patients with adrenal tumors."

Lopez and colleagues noted that previous research has indicated increased risks for cardiometabolic conditions, including insulin resistance, in patients with NFATs.

They evaluated 740 participants without adrenal tumors and 166 participants with benign NFATs over at least 3 years by reviewing medical records after abdominal imaging for any incident outcome developments.

Results showed that patients with NFATs had an increased risk for incident diabetes than participants without adrenal tumors (27.3% vs. 11.7%; adjusted risk ratio = 1.87; 95% CI, 1.17-2.98).

The researchers reported no other significant associations, but noted an association between higher postdexamethasone cortisol levels and increased type 2 diabetes prevalence and increased NFAT size.

"Given the high prevalence of incidentally discovered adrenal tumors that predominantly comprise benign NFATs, our findings have several important implications for general clinical practice and future research investigations," Lopez and colleagues wrote. "First, ‘nonfunctional’ may be an inadequate and misleading term to ascribe to benign adrenal tumors because it minimizes the potential continuum of adrenal hormone secretion that can contribute to cardiometabolic risk; therefore, the currently accepted criteria by which adrenal tumors are classified as nonfunctional may need reevaluation. Second, these findings underscore the importance of recognizing incidentally discovered adrenal tumors as independent risk factors for diabetes that may warrant more frequent surveillance for glucose intolerance."

The researchers also noted that future studies should focus on whether NFATs "secrete inappropriate amounts of glucocorticoid that evade current clinical practice and contribute to adverse outcomes." – by Chelsea Frajerman Pardes

Disclosures: Adler reports a grant from the National Institutes of Health during the conduct of the study. Turchin reports personal fees from Novo Nordisk and Monarch Medical Technologies and grants from Sanofi and Merck outside the submitted work. Vaidya reports grants from the National Institutes of Health and the Doris Duke Charitable Foundation during the conduct of the study and personal fees from the Endocrine Society outside the submitted work.