Evaluation of ABO/Rh Blood Group Distributions and Clinical Characteristics in Patients with Adrenal Incidentaloma: A Case-Control Study

Aim: Studies examining the relationship between endocrine organ diseases and ABO and Rh blood groups have been conducted, and some studies have shown that endocrine organ diseases may be associated with ABO/Rh blood groups. The aim of this study was to evaluate the ABO/Rh blood group distribution in patients with adrenal incidentaloma (AI) and its relationship with the clinical features of the patients. Methods: The study was conducted as a retrospective case-control study. Patients with AI who were followed up in the outpatient clinic of a single tertiary center between 2019 and 2023 were included in the study. The clinical (age, gender), radiological (diagnostic method, radiological features, adenoma size, localization), and biochemical (catecholamines, cortisol, aldosterone, and plasma-renin activity) characteristics of the patients were determined. The ABO and Rh blood group distributions of the patients were compared with those of the healthy control group. Results: The number of patients included in the study was 356 and the number of people in the healthy control group was 2,809,237. Adrenal incidentaloma was detected by computed tomography in 237 (67.1%) patients and was more often detected in the left adrenal gland (51.1%). The median size of the adrenal mass was 20 mm. Because of the hormonal evaluation, functional hormone production was detected in 16 (4.5%) patients. After further investigations, it was found that three (0.8%) patients had adrenal carcinoma and three (0.8%) patients had cancer metastases. ABO blood group distributions in the patients (42.7% A, 13.5% B, 9.6% AB, 34.3% O) and control groups (42% A, 16% B, 8% AB, 34% O) were found to be similar (p=0.9). Similar results were found in terms of the Rh factor (p=0.9). There was no statistically significant relationship between the distribution of ABO and Rh blood groups and clinical features such as age, gender, functional hormone release, mass size, and accompanying endocrine diseases. Conclusion: The ABO/Rh blood group was not found to be a risk factor in patients with AI. In addition, no relationship was found between clinical features and the ABO/Rh blood group in patients with AI.