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Background: Whether hyperthyroidism is an independent risk factor for cardiovascular events remains controversial. We aimed to evaluate the association of overt and subclinical hyperthyroidism with the risk of ischemic heart disease (IHD), stroke, heart failure, and cardiovascular mortality.Methods: Studies regarding the association between hyperthyroidism and cardiovascular events were searched on PubMed and Embase databases. The cardiovascular disease (CVD) risk was classified as high and low, based on pre-existing diseases, including history of coronary, cerebral, or peripheral artery disease; heart failure; atrial fibrillation; diabetes mellitus; or chronic kidney disease.Results: Thirty-seven cohort studies were included in this meta-analysis. The pooled hazard ratio for subjects with overt hyperthyroidism compared with the control group was 1.11 (95% confidence interval [CI], 1.03 to 1.19) for IHD, 1.35 (95% CI, 1.03 to 1.75) for stroke, and 1.20 (95% CI, 1.00 to 1.46) for cardiovascular mortality. For subjects with subclinical hyperthyroidism, the pooled hazard ratio was 1.24 (95% CI, 1.07 to 1.45) for IHD, when compared with the control group. Subgroup analysis by CVD risk showed that the risk of stroke in overt hyperthyroidism was increased in the low CVD risk group; however, these association was not observed in the high CVD risk group. Similarly, the risk of IHD in subjects with subclinical hyperthyroidism was significantly increased in the low CVD risk group.Conclusion: Overt hyperthyroidism is associated with increased risk of IHD, stroke, and cardiovascular mortality, and subclinical hyperthyroidism is associated with increased risk of IHD. These associations were particularly observed in the low risk CVD group without underlying CVD.

Background: There are limited data about whether patients who receive initial treatment for differentiated thyroid cancer (DTC) gain or lose weight during long-term follow-up under thyroid stimulating hormone (TSH) suppression. This study was aimed to evaluate whether DTC patients under TSH suppression experience long-term weight gain after initial treatment. We also examined the impact of the radioactive iodine ablation therapy (RAIT) preparation method on changes of weight, comparing thyroid hormone withdrawal (THW) and recombinant human TSH (rhTSH). Methods: We retrospectively reviewed 700 DTC patients who underwent a total thyroidectomy followed by either RAIT and levothyroxine (T4) replacement or T4 replacement alone. The control group included 350 age-matched patients with benign thyroid nodules followed during same period. Anthropometric data were measured at baseline, 1 to 2 years, and 3 to 4 years after thyroidectomy. Comparisons were made between weight and body mass index (BMI) at baseline and follow-up. Results: Significant gains in weight and BMI were observed 3 to 4 years after initial treatment for female DTC but not in male patients. These gains among female DTC patients were also significant compared to age-matched control. Women in the THW group gained a significant amount of weight and BMI compared to baseline, while there was no increase in weight or BMI in the rhTSH group. There were no changes in weight and BMI in men according to RAIT preparation methods. Conclusion: Female DTC patients showed significant gains in weight and BMI during long-term follow-up after initial treatment. These changes were seen only in patients who underwent THW for RAIT.

Background Previous studies have suggested that recombinant human thyroid stimulating hormone (rhTSH) stimulation is an acceptable alternative to thyroid hormone withdrawal (THW) when radioiodine remnant ablation is planned for thyroid cancer treatment, based on superior short-term quality of life with non-inferior remnant ablation efficacy. This study evaluated the cost-effectiveness of radioiodine remnant ablation using rhTSH, compared with the traditional preparation method which renders patients hypothyroid by THW, in Korean perspective. Methods This economic evaluation considered the costs and benefits to the Korean public healthcare system. Clinical experts were surveyed regarding the current practice of radioiodine ablation in Korea and their responses helped inform assumptions used in a cost effectiveness model. Markov modelling with 17 weekly cycles was used to assess the incremental costs per quality-adjusted life year (QALY) associated with rhTSH. Clinical inputs were based on a multi-center, randomized controlled trial comparing remnant ablation success after rhTSH preparation with THW. The additional costs associated with rhTSH were considered relative to the clinical benefits and cost offsets. Results The additional benefits of rhTSH (0.036 QALY) are achieved with an additional cost of Korean won W961,105, equating to cost per QALY of W26,697,361. Sensitivity analyses had only a modest impact upon cost-effectiveness, with one-way sensitivity results of approximately W33,000,000/QALY. Conclusion The use of rhTSH is a cost-effective alternative to endogenous hypothyroid stimulation prior to radioiodine ablation for patients who have undergone thyroidectomy in Korea.

Background: Follicular thyroid tumors harbor several genetic alterations such as RAS mutations and PAX8/PPARγ rearrangement. The aims of our study were to investigate the prevalence of RAS mutations and PAX8/PPARγ rearrangement in follicular thyroid tumors and to correlate RAS mutations and/or PAX8/PPARγ rearrangement with clinicopathologic features in Korean patients with follicular thyroid carcinomas. Methods: RAS mutations were investigated by polymerase chain reaction and DNA sequencing in surgical specimens of 37 follicular thyroid carcinomas (FTCs) and 16 follicular thyroid adenomas (FTAs). PAX8/PPARγ rearrangement was analyzed by fluorescent in situ hybridization in surgical specimens of 31 FTCs and 13 FTAs. Results: RAS mutations were detected in 30% (11 of 37) of FTCs and 19% (three of 16) of FTAs. Three of 11 FTC patients with RAS mutations died of thyroid cancer, but none of the 26 FTC patients without RAS mutations. PAX8/PPARγ rearrangement was found in 10% (three of 31) of FTCs, but in none of the 13 FTAs. All three FTC patients with PAX8/PPARγ rearrangement remained in complete remission during follow-up. There were no FTC patients with both RAS mutations and PAX8/PPARγ rearrangement. Conclusion: The prevalence of RAS mutations in our series of follicular tumors was similar to previous studies. The frequency of PAX8/PPARγ rearrangements in our group of FTC was lower than previous western reports, but higher than Japanese reports. RAS mutations may be associated with hematogeneous metastasis and poor survival while PAX8/PPARγ rearrangement may be related to more favorable prognosis in Korean patients with FTCs. (Endocrinol Metab 27:45-53, 2012)