Combined Treatment of Type 2 Diabetes and Hypothyroidism: Impact of Oral Semaglutide and Levothyroxine on Cardiometabolic and Thyroid Parameters: A 6-Month Comparative Study

BACKGROUND/OBJECTIVES: Type 2 diabetes (T2DM) and hypothyroidism often coexist, worsening cardiometabolic risk. Oral semaglutide and levothyroxine each improve metabolic parameters, but the effect of combined therapy is understudied. This study aimed to evaluate whether oral semaglutide administered concomitant with levothyroxine provides additive benefits on lipid profile, glycemic control, and body weight in patients with both conditions. METHODS: This prospective comparative observational study assessed a total of 210 patients who were enrolled (70 per group) with a 6-month follow-up. Group A (T2DM and hypothyroidism) received semaglutide and levothyroxine, group B (hypothyroidism only) received levothyroxine, and group C (T2DM only) received oral semaglutide. Lipid profile, glycemic profile (HbA1c), thyroid profile, and anthropometric parameters were comparable across groups at baseline and after 6 months. RESULTS: < 0.001 unless otherwise specified). In contrast, group B experienced worsening lipid profiles (LDL increased by 11.0%, HDL decreased by 0.5%, and triglycerides increased by 9.1%), while group C showed modest changes (LDL increased by 4.5%). Glycemic control improved among diabetic patients, with HbA1c declining by 7.7% in group A and 12.6% in group C. Body mass index (BMI) decreased in groups A (4.9%) and C (6.0%). CONCLUSIONS: The concurrent administration of oral semaglutide and levothyroxine produces additive cardiometabolic advantages in individuals with T2DM and hypothyroidism. These findings suggest that combined treatment may optimize metabolic outcomes in this particularly high-risk population.