Abstract

Introduction: Thyroid dysfunction (TD) is a common comorbidity in type 2 diabetes mellitus (T2DM), with bidirectional pathophysiological interactions. This study aimed to define its burden and correlates in a South Indian T2DM cohort. Methods: This retrospective observational study analyzed 1,055 randomly selected patient records. TD was defined using standard criteria. Patients were stratified into groups based on thyroid status. Statistical analyses included chi-square tests, t-tests, calculation of odds ratios (OR), and multivariate logistic regression. Results: The prevalence of TD was 14.7%, with clinical hypothyroidism (55.4% of TD cases) being predominant. Significant associations included female sex, family history of thyroid disease, BMI ≥25kg/m², advanced age, and anemia. Microvascular complications, especially diabetic retinopathy and erectile dysfunction, were strongly linked to TD, but not macrovascular events. Medication use analysis revealed that metformin and insulin were independently associated with overall TD and hypothyroidism after multivariate adjustment, and statin use was marginally linked with hypothyroidism. Simple prevalence associations for sulfonylureas, alpha-glucosidase inhibitors, and beta-blockers did not remain significant after adjustment. Conclusion: TD is common in South Indian T2DM patients and linked to specific risk factors and microvascular complications. The associations of key medications with TD likely reflect underlying metabolic disease severity, underscoring the need for routine thyroid screening and rigorous statistical analysis.