In adults with adrenal incidentaloma, adiponectin levels may help predict the presence of subclinical Cushing’s disease, according to recent findings.
Asli Dogruk Unal,
MD, of the department of endocrinology and metabolism at Memorial Atasehir Hospital in Istanbul, and colleagues analyzed data from 40 patients with adrenal incidentaloma (24 women; mean age, 61 years) and 30 metabolically healthy adults without adrenal adenomas or hyperplasia (22 women; mean age, 26 years). All patients with type 2 diabetes were newly diagnosed and not on any antidiabetic therapies; included patients were not using statin therapy for about 12 weeks. Participants provided blood samples
Among patients with adrenal incidentaloma, eight (20%) were diagnosed with subclinical Cushing’s syndrome; median adenoma diameter in these patients was 3.05 cm. The remaining patients were classified as nonfunctional adrenal incidentaloma. Compared with patients who had nonfunctional adrenal incidentaloma, patients with subclinical Cushing’s syndrome had a higher median midnight cortisol level (9.15 µg/dL vs. 5.1 µg/dL; P = .004) and urinary free cortisol level (249 µg per 24 hours vs. 170 µg per 24 hours; P = .007).
In two group comparisons, researchers found that only adiponectin level was lower in the subclinical Cushing’s syndrome group vs. the nonfunctional adrenal incidentaloma group (P = .007); there were no observed between-group differences for age, BMI, waist circumference, insulin levels, homeostasis model assessment for insulin resistance (HOMA-IR) or lipid profiles.
Adiponectin level was negatively associated with insulin level, HOMA-IR, triglyceride level and midnight cortisol level, and was positively associated with body fat percentage, HDL and adrenocorticotropic hormone levels. In linear regression analysis, age was found to be an increasing factor, whereas sex, HOMA-IR, LDL, waist circumference and presence of subclinical Cushing’s syndrome were decreasing factors.
In evaluating the receiver operating characteristic analysis, researchers found that adiponectin level had a predictive value in determining the presence of subclinical Cushing’s syndrome (area under the curve: 0.81; 95% CI, 0.67-0.96). Sensitivity and specificity for an adiponectin value of 13 ng/mL or less in predicting the presence of subclinical Cushing’s syndrome were 87.5% and 77.4%, respectively; positive predictive value and negative predictive value were 50% and 96%, respectively.
“Presence of [subclinical Cushing’s syndrome] should be considered in case of an adiponectin level of 13 ng/mL in [adrenal incidentaloma] patients,” the researchers wrote. “Low adiponectin levels in [subclinical Cushing’s syndrome] patients may be important in treatment decision due to the known relation between adiponectin and cardiovascular events. In order to increase the evidences on this subject, further prospective follow-up studies with larger number of subjects are needed.” – by Regina Schaffer
Disclosure: The researchers report no relevant financial disclosures.