Changes in metabolic hormones after bariatric surgery and their predictive impact on weight loss.

BACKGROUND: Although various metabolic hormones have been implicated in bariatric-related weight loss, their use as predictors of weight loss is unknown. Our study evaluates changes in metabolic hormones after bariatric surgery, and their role as predictors of weight loss. METHODS: This nonrandomized study included 51 patients, 21 underwent laporascopic adjustable gastric banding (LAGB), 15 laparoscopic sleeve gastrectomy (LSG) and 15 Roux-en Y gastric bypass (RYGB). Serum ghrelin, leptin, insulin, growth hormone, HOMA-IR and HOMA-ß was recorded at baseline and 1, 3, 6 and 12 months, and correlated with weight loss. Successful weight loss was defined as excess weight loss >50% at 12 months for all groups. RESULTS: Weight loss pattern was similar in all groups. Ghrelin increased only in the LAGB group (P = 0·016). However, baseline ghrelin concentrations >664·6 pg/mL in the LSG group predicted successful weight loss with 81·8% sensitivity and 100·0% specificity, and ghrelin >969·8 pg/mL in the 1st postoperative month predicted success with 83·3% sensitivity and 83·3% specificity in the LAGB group. Insulin and HOMA-IR decreased significantly in the LSG and RYGB group, HOMA-ß increased in the LAGB and LSG group. Serum leptin decreased and GH increased in all groups (P < 0·001 for all changes). Changes in insulin, leptin and growth hormone were not predictors, but a consequence of weight loss. CONCLUSIONS: LSG is the most effective procedure for improvement of beta-cell function. High baseline ghrelin in the LSG group and an adequate 1st month increase in the LAGB group are associated with greater weight loss. Validation studies are required to confirm the role of ghrelin in predicting weight loss after bariatric surgery, but also in selecting candidates for specific bariatric procedures.

Re-ablation I-131 activity does not predict treatment success in low- and intermediate-risk patients with differentiated thyroid carcinoma.

The aim of this study was to evaluate the efficacy of different radioactive iodine (I-131) activities used for re-ablation, to compare various combinations of treatment activities, and to identify predictors of re-ablation failure in low- and intermediate-risk differentiated thyroid carcinoma (DTC) patients. The study included 128 consecutive low- and intermediate-risk patients with DTC with ablation failure after total thyroidectomy. Patient characteristics, T status, tumor size, lymph node involvement, postoperative remnant size on whole-body scintigraphy, serum thyroglobulin (Tg), thyroid-stimulating hormone (TSH), anti-Tg antibody (TgAb), and Tg/TSH ratio were analyzed as potential predictors of the re-ablation success. Re-ablation was successful in 113 out of 128 patients (88.3 %). Mean first I-131 activity was 2868 ± 914 MBq (77.5 ± 24.7 mCi) and mean second I-131 activity 3004 ± 699 MBq (81.2 ± 18.9 mCi). There was no association between the first, second, and cumulative activity with re-ablation treatment outcome. Treatment failure was associated with higher Tg levels prior to re-ablation (Tg2) (OR 1.16, 95 % CI 1.05-1.29, P = 0.003) and N1a status (OR 3.89, 95 % CI 1.13-13.41, P = 0.032). After excluding patients with positive-to-negative TgAb conversion, Tg2 level of 3.7 ng/mL predicted treatment failure with a sensitivity of 75.0 %, specificity of 80.5 %, and a negative predictive value of 97.1 %. Patients with positive-to-negative TgAb conversion had higher failure rates (OR 2.96, 95 % CI 0.94-9.29). Re-ablation success was high in all subgroups of patients and I-131 activity did not influence treatment outcome. Tg may serve as a good predictor of re-ablation failure. Patients with positive-to-negative TgAb conversion represent a specific group, in whom Tg level should not be used as a predictive marker of treatment outcome.