Evaluation of Thyroid Dysfunction in Type 2 Diabetes Mellitus Patients and Its Association With Diabetic Complications: A Cross-Sectional Study

Background Type 2 diabetes mellitus (T2DM) is a widespread metabolic disorder that contributes significantly to morbidity and mortality due to its associated complications. Among these, thyroid dysfunction is one of the most common and may play a role in the progression of diabetic complications. This study explores the relationship between thyroid dysfunction and both microvascular and macrovascular complications in individuals with T2DM. Methods This cross-sectional observational study was conducted among 200 patients with T2DM, aged 30-70 years, at the Department of General Medicine, Gujarat Medical Education and Research Society (GMERS) Medical College and Hospital, Valsad, India. Participants were screened for thyroid dysfunction and diabetic complications, including retinopathy, nephropathy, neuropathy, and peripheral arterial disease (PAD). Blood tests were performed to measure thyroid hormone levels (thyroid-stimulating hormone, free triiodothyronine, and free thyroxine) and diabetes-related parameters such as glycated hemoglobin (HbA1c). Data were analyzed using chi-square tests and multivariate regression analysis to evaluate the correlation between thyroid dysfunction and the development of diabetic complications. Results The prevalence of thyroid dysfunction in the study population was 26.5%, with hypothyroidism being more common (84.9%) than hyperthyroidism (15.1%). Diabetic complications were significantly more prevalent among individuals with hypothyroidism compared to those with normal thyroid function. Hypothyroidism was independently associated with increased odds of diabetic retinopathy (OR = 7.72), diabetic nephropathy (OR = 4.87), neuropathy (OR = 3.10), and PAD (OR = 8.12). In contrast, hyperthyroidism showed no significant association with diabetic complications. Conclusions Hypothyroidism in individuals with T2DM is significantly associated with a higher risk of both microvascular and macrovascular complications. These findings highlight the importance of incorporating thyroid function assessment into routine diabetic care, as optimizing thyroid hormone levels may help mitigate the risk of these complications.