Patterns of Body Weight Changes in Patients With Hypothyroidism, a Retrospective Study From Basrah, Southern Iraq

Background: Weight gain is one of the most important hypothyroidism-related concerns among patients with hypothyroidism. However, not as expected, thyroxine replacement does not necessarily result in body weight (BWT) reduction among those patients. The study aimed to assess the patterns of BWT changes through time in patients with hypothyroidism. Method: A retrospective database study from Faiha Specialized Diabetes, Endocrine, and Metabolism Center. A total of 346 adult patients with hypothyroidism, 192 newly diagnosed and 154 known, who had 1 visit every 3 months, 5 visits per one year. From those patients, 116 new and 69 known had completd 9 visits per two years. Each visit involved thyroid-stimulating hormone (TSH) and BWT measurements. Patients with chronic liver or renal disease, diabetes mellitus, thyroid cancer, or other malignancies, pregnancy, and on steroid or hormonal therapies were excluded. The patients were further subdivided based on average TSH levels into controlled (TSH≤4.2 μIU/mL) and uncontrolled TSH>4.2 μIU/mL. Repeated measures ANOVA with a Greenhouse-Geisser correction and Post hoc tests using the Bonferroni correction were used to evaluate BWT changes through the study. Results: Both newly diagnosed and known hypothyroidism, over one and two years, in patients with average TSH>4.2 μIU/mL, BWT increased significantly through visits. For newly diagnosed over one year, (F(2.41, 321.60) = 3.28, p = 0.03), and mean BWT increase = 1.4 ± 0.38 kg from 3(rd) to 12(th) month visits, (p = 0.004). For newly diagnosed over two years, (F(3.10, 263.89) = 9.08, P < 0.0005), mean BWT increase = 3.02 ± 0.77 kg from 3(rd) to 24(th) month visits, (p = 0.007). And for known hypothyroidism over one year, (F(2.56, 187.47) = 7.11, p = 0.0003), mean BWT increase = 1.97 ± 0.64 kg at 12(th) month visit, and over two years, (F(2.35, 77.56) = 4.67, P = 0.009), mean BWT increase = 3.78 ± 1.26 kg at 24(th) month visit. While in all other patients with average TSH≤4.2 μIU/mL, the BWT changed non-significantly through visits. For newly diagnosed patients over one year and two years (p = 0.10, 0.34 respectively), and known patients over one year and two years (p = 0.47, 0.34 respectively). Conclusion: In contrary to what is believed, adequate treatment with thyroxine does not associate with weight reduction. Instead, either the patient kept on the same weight or continued to gain more weight.