Endocrine Abstracts

Aim

Nonfunctional adrenal incidentalomas (NFAI’s) are often associated with a high prevalence of insulin resistance (IR). The relationship between IR and thyroid diseases, as well as, thyroid cancer (TC) in patients with NFAI is not yet understood. The aim of this study is to determine the frequency of thyroid disease and TC in NFAI patients and to investigate any possible association of thyroid disease with IR and metabolic disturbances in NFAI patients.

Material and method

In our study, patients with NFAI and patients with normal adrenal imaging between 2010 and 2020 were evaluated retrospectively. 126 patient with NFAI and 114 patient with normal adrenal imaging were included in the study. Fasting blood glucose (FBG), fasting insulin, lipid profile, C-reactive protein (CRP), serum free triiodothyronine (fT3), free thyroxine (fT4), thyroid stimulating hormone (TSH), thyroid autoantibody (anti-Tg and anti-TPO) levels, thyroid ultrasonography and thyroidectomy results were registered retrospectively. IR was evaluated using homeostasis model assessment (HOMA-IR).

Results

There were no significant differences between NFAI and the control group in terms of age and gender. The average BMI of NFAI group was higher than the control group (29.5 ± 4.9 vs 27.4 ± 4.7, P < 0.001). Fasting insulin, HOMA-IR, total cholesterol, LDL cholesterol and serum CRP levels were significantly higher in the NFAI group (P < 0.05). FBG, HDL cholesterol, triglyceride, TSH, fT3 levels were similar in both groups. NFAI group had lower mean fT4 levels than the control group (P = 0.027). NFAI group had higher prevalence of positive anti-TPO and anti-Tg antibodies than the control group (%36.5 vs 23.7% and 29.4% vs 17.5%, respectively) (P = 0.031, P = 0.032, respectively). At least one thyroid nodule was detected in 89 (70.6%) NFAI group compared to 48 (42.1%) in the control group (P < 0.001). In NFAI group; there were 3 patients (2.4%) with diffuse goiter, 6 patients (4.8%) with uninodular goiter, 34 patients (27.0%) with multinodüler guatr (MNG), 3 patients (2.4%) with toxic MNG, 1 patient (0.8%) with Graves disease.TC was detected in 9 (7.1%) of NFAI group. MNG and TC were significantly more common in patients with NFAI (P < 0.001, P = 0.046, respectively).

Conclusion

In our study it was found that patients with NFAI had an elevated risk of IR and metabolic disturbance. Also it was detected that patients with NFAI have increased risk of autoimmune thyroiditis, nodular thyroid disease, MNG and TC. Therefore, it would be appropriate to screen NFAI patients with thyroid function test and thyroid ultrasonography as well as metabolic parameters.