‘Nonfunctional’ adrenal tumors may be linked to incident diabetes
Risk for incident diabetes is significantly higher in patients with nonfunctional adrenal tumors than in those without, and the term “nonfunctional” may minimize the potential contribution of adrenal hormone secretion to cardiometabolic risk, researchers said.
Adrenal tumors previously considered nonfunctional and benign may be related to higher risk for incident diabetes, a recent study has shown.
Researchers performed a cohort study of 166 patients with nonfunctional adrenal tumors in an integrated hospital system to determine whether they had increased an risk for cardiometabolic outcomes. Patients who had benign adrenal tumors (the exposed group) were compared with those who did not (the unexposed group) over at least 3 years of follow-up. Patients' medical records were reviewed from the time of abdominal imaging to determine development of hypertension, prediabetes or type 2 diabetes, hyperlipidemia, cardiovascular events, and chronic kidney disease. Independent associations between exposure status and incident outcomes were evaluated in the primary analyses, while relationships between nonfunctional adrenal tumors and cortisol physiology were evaluated in the secondary analyses. The study results were published online Aug. 2 by Annals of Internal Medicine.
The 166 patients in the exposed group were compared with 740 patients in the unexposed group. Most patients (77.7% in the exposed group and 70.7% in the unexposed group) were women. Mean follow-up was 7.2 years in patients with nonfunctional adrenal tumors and 7.8 years in those without. During follow-up, patients who had nonfunctional adrenal tumors were at significantly higher risk for incident prediabetes or type 2 diabetes than those without adrenal tumors (27.3% vs. 11.7% of patients; absolute risk, 15.6% [95% CI, 6.9% to 24.3%]; adjusted risk ratio, 1.87 [95% CI, 1.17 to 2.98]). Nonfunctional adrenal tumors did not appear to be associated with any of the other examined outcomes. An association was seen between higher “normal” levels of postdexamethasone cortisol (all levels ≤50 nmol/L; highest prevalence in those with levels of 38.5 to 50.0 nmol/L) and both larger tumor size and higher prevalence of type 2 diabetes.
The authors noted that their study was observational, that selection bias may have played a role in their classification of nonfunctional adrenal tumors, that adrenocorticotropic hormone levels were not available for analysis, and that their findings may not be generalizable to men, among other limitations. However, they concluded that risk for incident diabetes is significantly higher in patients with nonfunctional adrenal tumors than in those without and that the term “nonfunctional” may minimize the potential contribution of adrenal hormone secretion to cardiometabolic risk. Also, they wrote, their 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.” They called for future studies to examine the potential role of nonfunctional adrenal tumors in adverse outcomes.