The Correlation Between Insulin Resistance Markers and Autoimmunity in Patients with Autoimmune Hypothyroidism in the Absence of Diabetes Mellitus

Background: Autoimmune Hypothyroidism (AIH), predominantly caused by Hashimoto thyroiditis, is associated with metabolic alterations, including Insulin Resistance (IR). Understanding the baseline clinical and laboratory profile of patients with AIH is crucial for evaluating the interplay between thyroid autoimmunity and metabolic dysfunction. Objective: To describe and analyze the demographic, anthropometric, and laboratory features of patients with overt and subclinical autoimmune hypothyroidism, with a focus on the association between insulin resistance and thyroid autoimmunity. Patients and Methods: This cross-sectional analysis was conducted on a cohort of patients (including 61 female patients) with autoimmune hypothyroidism (both overt and subclinical). Demographic data, anthropometric measures, thyroid function tests, Thyroid Autoantibodies (TPO-Ab), glycemic indices, and Homeostatic Model Assessment-IR (HOMA-IR) were collected before intervention. Results: Patients with overt hypothyroidism exhibited significantly higher TSH and TPO-Ab levels compared to those with subclinical hypothyroidism (p<0.001). Insulin resistance, as assessed by HOMA-IR, was more prevalent among overt cases. Baseline analysis showed significant correlations between HOMA-IR and TPO-Ab titers (r=0.302), suggesting a link between insulin resistance and thyroid autoimmunity. Anthropometric parameters such as BMI and waist circumference were also elevated in insulin-resistant patients. Conclusion: The baseline characteristics of AIH patients reveal a strong association between insulin resistance and autoimmune activity. These findings provide the foundation for assessing the potential impact of dietary and metabolic interventions in modifying the course of autoimmune thyroid disease.