SAT-436 Long-Term Analysis of Weight Change Following Thyroidectomy

Introduction: Weight gain is a common source of apprehension for patients undergoing thyroidectomy. However, contradictory reports exist regarding the presence and degree of weight gain following thyroid surgery and all known studies have short term follow-up This study evaluated weight changes following total thyroidectomy (TT) and lobectomy (L) over an extended time period. Methods: Retrospective analysis was performed of weight changes following surgery for patients who underwent TT or L (n=387) as compared with those undergoing parathyroidectomy for primary hyperparathyroidism (n=201) in a tertiary referral hospital between 2007-2012. Clinical, demographic and pre- and postoperative weight data was collected with a median follow-up of 55.6 months. Results: Postoperative weight change was observed at 1, 6, 12, and 36-months in patients who underwent TT (μ=+0.21kg, μ=+1.33kg, μ=+0.59kg, μ=+0.60kg; p<0.05) and at 6-months for patients who underwent L (μ=+0.93kg, p<0.05) compared with those who underwent parathyroidectomy. Patients having TT and L showed a general trend of weight gain compared to the control group up to 108-months post-operation; however, this weight gain was non-significant (p<0.05). Significant postoperative weight gain was observed in patients who had TT (1-month μ=+0.40kg, 6-months μ=+2.14kg, and 12-months μ=+1.40kg) and L (6-months μ=+1.04kg) for benign conditions compared with the parathyroidectomy group. Patients who had TT gained 0.40kg more than L patients at 12-months post-op (p<0.05), but no significant difference existed at other time points up to 108-months. Tukey HSD post-hoc analysis showed weight gain in benign, thyroiditis, and thyroid cancer patient groups was not significantly different from 6-months to 108-months post-operation. Furthermore, neither race nor sex was correlated with weight gain. Relative risks with 95% CI for weight gain following TT and L compared to control are: 1-month TT=1.74, 0.96-3.14, L=1.59, 0.58-2.58; 6-month TT=1.27, 0.85-1.89, L=1.42, 0.85-2.11; 12-month TT=1.44, 0.92-2.28, L=1.34, 0.86-2.36; 24-month TT=1.17, 0.82-1.67, L=1.22, 0.69-1.60. In the group of patients who gained greater than 2kg, those who underwent TT had significant weight increase compared to the parathyroidectomy group at 6-months postoperatively (Mann-Whitney U, p=0.011). In the subgroup of patients with weight gain greater than 2kg, those who had L did not have significant weight increase at any time point. Conclusion: Weight change following TT when compared with parathyroidectomy is significant shortly after surgery. However, these changes are not significant at long-term follow-up.