Evaluating the Prevalence and Predictors of Thyroid Dysfunction in Patients with Type 2 Diabetes Mellitus

A BSTRACT Background: Diabetes mellitus (DM) and thyroid disorders are among the most prevalent endocrine diseases. Uncontrolled DM can disrupt thyroid metabolism and alter plasma levels of thyroid hormones. Objectives: This study aims to determine the prevalence, risk factors, and types of thyroid dysfunction in a type 2 diabetic population attending a public sector tertiary care teaching hospital. Materials and Methods: This analytical cross-sectional study was conducted at the Department of Biochemistry, Nepalgunj Medical College and Teaching Hospital Kohalpur, Nepal, from January 1, 2023 to January 28, 2024. The study comprised 200 patients diagnosed with type 2 DM (T2DM) according to the American Diabetes Association (ADA) criteria. Inclusion criteria included fasting blood glucose ≥126 mg/dl, HbA1c >6.5%, and 2-hour postprandial blood glucose levels >200 mg/dl. Results: Among the 200 enrolled patients with T2DM, 120 (60%) were female, with a mean age of 55.07 ± 3.10 years. The mean duration of diabetes mellitus, fasting blood sugar, postprandial blood sugar, BMI, and HbA1c were 14.31 ± 6.76 (years), 182.30 ± 75.14 (mg/dl), 292.87 ± 105.39 (mg/dl), 27.80 ± 3.17 (kg/m 2 ), and 9.65 ± 2.02 (%), respectively. The mean levels of FT3, FT4, and TSH were 2.89 ± 0.87 (pg/ml), 1.17 ± 0.34 (ng/dl), and 7.82 ± 7.61 (μIU/ml), respectively. Thyroid dysfunction was observed in 74 patients (37%), with 36 (18%) having subclinical hypothyroidism, 24 (12%) with clinical hypothyroidism, 6 (3%) with clinical hyperthyroidism, and 8 (4%) with subclinical hyperthyroidism. Risk factors for thyroid dysfunction in T2DM patients identified in this study included: age: OR 1.059 ([CI] 1.007–1.113, P < 0.05); female gender: OR 0.212 (95% CI 0.108–0.418, P < 0.001); BMI: OR 1.297 (95% CI 1.121–1.501, P < 0.001); family history of DM: OR of 3.432 (CI 1.498–7.863, P = 0.004); HbA1c: OR 1.303 (95% CI 1.078–1.575, P = 0.006). Conclusion: The prevalence of thyroid dysfunction is notably higher among patients with T2DM, with hypothyroidism being the most common form. This condition is more prevalent among female patients. Regular screening for thyroid dysfunction in the T2DM population is recommended to manage and address potential complications effectively.