Assessment of Body Mass Index Changes after Levothyroxine Therapy in Patients with Hypothyroidism

Open Access

Abstract

Background: Hypothyroidism is a common endocrine disease that is marked by inadequate production of thyroid hormone, which is usually manifested by weight gain and increased body mass index (BMI). The study aimed to evaluate the BMI changes after levothyroxine treatment in patients with hypothyroidism. Methods & Materials: This prospective study was carried out at the Department of Pharmacology, Dhaka Medical College, between January and December 2022. Purposive sampling was used to enroll 30 adult patients (≥18 years) with newly diagnosed hypothyroidism. Every patient was put on levothyroxine therapy with a dose increase every 4-6 weeks until euthyroidism was attained. At baseline and 12 weeks, anthropometric and thyroid hormone parameters were measured. Data were entered and analyzed using SPSS version 26. Results: Most of the patients were women (96.7%) with an average age of 20-39 years. The baseline consisted of 43.3% overweight and 33.3% obese. Following 3 months of levothyroxine therapy, mean weight declined significantly from 65.84 ± 10.21 kg to 64.98 ± 10.10 kg (p<0.001), and mean BMI decreased from 27.93 ± 3.66 to 27.56 ± 3.56 kg/m² (p<0.001). FT4 increased significantly (8.06 to 16.40 pmol/L, p<0.001), while TSH normalized (32.55 to 2.52 mIU/L, p<0.001). Weakness, fatigue, constipation, weight gain, and menstrual irregularity were improved symptomatically. Conclusion: Levothyroxine treatment led to decreases in body weight and BMI and normalization of thyroid hormone levels and clinical symptoms. These results confirm the metabolic advantage of early LT4 treatment in hypothyroid patients.