Liothyronine Use in Hypothyroidism and its Effects on Cancer and Mortality

Background: The prescription of liothyronine (LT3) to treat hypothyroidism is increasing worldwide; however, the long-term safety of LT3 use has yet to be determined. Previous studies have suggested a possible association between LT3 use and breast cancer. The aim of this study was to examine the effects of LT3 use on cancer incidence and mortality. Methods: Our sample included the full adult population of individuals living in Sweden with at least three purchases of thyroid hormone therapy between July 2005 and December 2017. Individual-level data on drug purchases were linked to registry data on cancer incidence and mortality. There were 575,461 individuals with at least three purchases, of which 11,147 had made at least three purchases of LT3, including combinations of levothyroxine (LT4) and LT3. Individuals were followed for a median follow-up time of 8.1 years. We applied Cox regression with a time-varying exposure variable, comparing LT3 users (individuals with at least three cumulative purchases of LT3) with LT4-only users (the rest). Outcomes included breast cancer incidence, any cancer incidence, all-cause mortality, any cancer mortality, and breast cancer mortality. We adjusted for age, sex, previous thyroid cancer, previous other cancer, use of antithyroid preparations, use of sex hormones, and dose in multivariate analyses. Results: Multivariate analyses produced a hazard ratio of 0.93 (95% confidence interval [0.75-1.15]) for breast cancer incidence (only females), 0.97 (0.87-1.08) for any cancer incidence, 0.69 (0.61-0.77) for all-cause mortality, 0.78 (0.62-0.98) for any cancer mortality, and 0.91 (0.50-1.66) for breast cancer mortality (only females). Conclusions: In this large, Swedish, long-term registry-based study, the use of LT3 did not lead to increased breast cancer incidence, any cancer incidence, all-cause mortality, any cancer mortality, or breast cancer mortality compared with LT4 use. Somewhat surprisingly, there was evidence of lower mortality in LT3 users in models adjusting for dose, potentially an artifact of underlying associations between dose and health status/diagnosis

Assessing the impact of short-term Lugol’s solution on toxic nodular thyroid disease: a pre-post-intervention study

PurposePreoperative iodine therapy in toxic nodular goiter (TNG) is discouraged as iodine may cause aggravation of hyperthyroidism. We aimed to examine if a short course of iodine treatment is safe to administer in TNG.MethodsPatients with TNG (n=20) and subclinical to mild hyperthyroidism (free (f)T4 <30 pmol/L) without complicating illnesses were included in this pre-post-intervention study at Karolinska University Hospital. All participants received Lugol’s solution 5%, three oral drops thrice daily for 10 days. Heart rate, TSH, fT4, fT3 concentrations were collected before (day 0) and after treatment (day 10). Thyroid hormone concentrations were also measured at two time points during treatment to discover aggravations of hyperthyroidism. ThyPRO39se, a quality-of-life questionnaire, was filled out day 0 and day 10. Differences in heart rate, thyroid hormone concentrations, and quality-of-life before and after treatment were compared. Adverse reactions were reported.ResultsThe median age was 63.5 years. Female to male ratio 19:1. FT4 and fT3 concentrations decreased (both p<0.001), and TSH concentration increased (p<0.001) after 10 days of treatment. There was no difference in heart rate. No aggravations of thyrotoxicosis were noticed in any of the participants. ThyPRO39se scores improved on three scales, including hyperthyroid symptoms, while the remaining scale scores were unchanged. Mild and transient symptoms related to or possibly related to treatment were observed in six participants.ConclusionA short course of Lugol’s solution improved thyroid hormone concentrations, reduced patient-reported hyperthyroid symptoms and was safe in TNG. Lugol’s solution might be an option for preoperative treatment in TNG.Clinical trial registrationhttps://www.clinicaltrials.gov, identifier NCT04856488

Corrigendum: Effects on Subclinical Heart Failure in Type 2 Diabetic Subjects on Liraglutide Treatment vs. Glimepiride Both in Combination with Metformin: A Randomized Open Parallel-Group Study

ObjectiveWe aimed to investigate the effect of liraglutide treatment on heart function in type 2 diabetes (T2D) patients with subclinical heart failure.MethodsRandomized open parallel-group trial. 62 T2D patients (45 male) with subclinical heart failure were randomized to either once daily liraglutide 1.8 mg, or glimepiride 4 mg, both add on to metformin 1 g twice a day. Mitral annular systolic (s′) and early diastolic (e′) velocities were measured at rest and during bicycle ergometer exercise, using tissue Doppler echocardiography. The primary endpoint was 18-week treatment changes in longitudinal functional reserve index (LFRIdiastolic/systolic).ResultsClinical characteristics between groups (liraglutide = 33 vs. glimepiride = 29) were well matched. At baseline left ventricle ejection fraction (53.7 vs. 53.6%) and global longitudinal strain (−15.3 vs. −16.5%) did not differ between groups. There were no significant differences in mitral flow velocities between groups. For the primary endpoint, there was no treatment change [95% confidence interval] for: LFRIdiastolic (−0.18 vs. −0.53 [−0.28, 2.59; p = 0.19]), or LFRIsystolic (−0.10 vs. −0.18 [−1.0, 1.7; p = 0.54]); for the secondary endpoints, there was a significant treatment change in respect of body weight (−3.7 vs. −0.2 kg [−5.5, −1.4; p = 0.001]), waist circumference (−3.1 vs. −0.8 cm [−4.2, −0.4; p = 0.019]), and heart rate (HR) (6.3 vs. −2.3 bpm [−3.0, 14.2; p = 0.003]), with no such treatment change in hemoglobin A1c levels (−11.0 vs. −9.2 mmol/mol [−7.0, 2.6; p = 0.37]), between groups.Conclusion18-week treatment of liraglutide compared with glimepiride did not improve LFRIdiastolic/systolic, but however increased HR. There was a significant treatment change in body weight reduction in favor for liraglutide treatment