Abstract
OBJECTIVES: Primary - a study of the correlation between serum osteoprotegerin (OPG), and biomarkers of bone metabolism in patients with treatment-naive Graves' disease (GD). Secondary - serum level of OPG, TNF-alfa, and biomarkers of bone metabolism in patients three months after treatment of GD with methimazole (MMI). MATERIALS AND METHODS: A total of thirty-five treatment-naive newly diagnosed GDs were recruited for the study, most of them female. All patients started with MMI for treatment and various blood parameters were measured at baseline and three months after treatment. Measurements: Serum calcium (Ca), phosphorus (P), bone-specific alkaline phosphatase (B-ALP), OPG, TNF-alfa, and urine deoxypyridinoline (U-DPD) along with serum-free T3 and T4, thyroid-stimulating hormone (TSH) and thyroid receptor antibody (TR-ab) were analysed at baseline and three months after MMI treatment. All the patients had euthyroid at three months of MMI treatment. RESULTS: Mean serum OPG (0.94 ± 1.39 vs. 0.63 ± 0.27 ng/ml; P = 0.262) level at baseline and after treatment with MMI did not show any significant change. Mean TSH level (0.207 ± 0.59 vs. 1.00 ± 1.95, P = 0.025) was significantly low at baseline than after treatment; FT4 (5.9 ± 5.22 v 1.77 ± 1.89 ng/dl; P < 0.001), FT3 (12.19 ± 6.91 vs. 4.99 ± 3.55 pg/ml; P < 0.001), and TNF-alfa values decreased significantly after treatment, however, PTH (58.09 ± 28.75 vs. 75.57 ± 41.50; P < 0.026) increased significantly after treatment. DISCUSSION: There is no correlation of OPG with thyroid hormone profile, TSH, thyroid receptor antibody (TR-ab), and bone metabolic parameters such as serum Ca, P, B-ALP, TNF-alfa, and U-DPD in our study. Mean TNF-alfa decreased significantly (393.43 ± 270.473 vs. 139.34 ± 101.264 pg/ml; P = 0.001) level after treatment with MMI. TNF-alfa was positively correlated with TR-ab (r = 0.374; P = 0.027) and B-ALP (r = 0.388; P = 0.021). CONCLUSION: The bone turnover marker in GD seems to be mediated other than OPG. We observed an increase in circulating TNF-alfa in GD with a significant decrease after treatment. TNF-alfa could be a marker of GD activity as evidenced by a close positive correlation with TR-ab, a sensitive marker of GD autoimmunity. TNF-alfa could be a factor associated with bone turnover markers in GD despite its euthyroid state.