Normal Thyroid-stimulating Hormone Levels Research Articles

Reduced pituitary size in subjects with mutations in the THRB gene and thyroid hormone resistance.

BackgroundThyroid hormone action is mediated by two forms of thyroid hormone receptors (α, β) with differential tissue distribution. Thyroid hormone receptor β (TRβ) mutations lead to resistance to thyroid hormone action in tissues predominantly expressing the β form of the receptor (pituitary, liver). This study seeks to identify the effects of mutant TRβ on pituitary size.MethodsHigh-resolution 3D T1-weighted magnetic resonance images were acquired in 19 patients with RTHβ in comparison to 19 healthy matched controls. Volumetric measurements of the pituitary gland were performed independently and blinded by four different raters (two neuroradiologists, one neurologist, one neuroscientist).ResultsPatients with mutant TRβ (resistance to thyroid hormone β, RTHβ) showed elevated free tri-iodothyronine/thyroxine levels with normal thyroid-stimulating hormone levels, whereas healthy controls showed normal thyroid hormone levels. Imaging revealed smaller pituitary size in RTHβ patients in comparison to healthy controls (F(1,35) = 7.05, P = 0.012, partial η2 = 0.17).ConclusionRTHβ subjects have impaired sensitivity to thyroid hormones, along with decreased size of the pituitary gland.

Specific impact of cardiovascular risk factors on coronary microcirculation in patients with subclinical hypothyroidism.

BackgroundAlthough thyroid hormones have significant effect on cardiovascular system, the impact of subtle thyroid dysfunction such as subclinical hypothyroidism (SCH) remains to be determined. We investigated coronary flow reserve (CFR) in patients with subclinical hypothyroidism.MethodsThirty two subjects with SCH and eighteen control subjects with normal serum thyroid hormones and thyroid-stimulating hormone (TSH) levels were included in the study. TSH, free thyroxine, free triiodothyronine, glucose, insulin, HbA1c, cholesterol, triglyceride and plasma levels of C-reactive protein were measured. Coronary diastolic peak flow velocities in left anterior descending coronary artery were measured at baseline and after adenosine infusion. CFR was calculated as the ratio of hyperemic to baseline diastolic peak velocity.ResultsCFR values were not significantly different between the two groups (SCH 2.76±0.35 vs controls 2.76±0.42). There was a significant correlation of CFR with waist to hip ratio, hypertension, smoking habits, markers of glucose status (glucose level, HbA1c, insulin level, HOMA IR), cholesterol, LDL-cholesterol and triglyceride levels in SCH group, whereas only cholesterol level showed significant correlation with CFR in controls. There was no correlation between CFR and thyroid hormones.ConclusionsWe concluded that there is a different impact of cardiovascular risk factors on CFR in SCH patients compared to healthy control and that these two groups behave differently in the same circumstances under the same risk factors. The basis for this difference could be that the altered thyroid axis "set point" changes the sensitivity of the microvasculature in patients with SCH to known risk factors.

Abstract 10993: Prognostic Value of Low T 3 Syndrome in Patients with Acute Decompensated Heart Failure in Osaka Prefectural Acute Heart Failure Registry (OPAR)

Backgrounds: It is widely recognized that thyroid dysfunction is a potential cause of heart failure (HF). In HF, one of the alterations of thyroid functions is referred to as low T 3 syndrome marked by a reduction in serum free triiodothyronine (T 3 ) with normal levels of thyroid-stimulating hormone (TSH). However, there is little information available about the association between low T 3 syndrome and future cardiac events in patients with acute decompensated heart failure (ADHF), relating to left ventricular ejection fraction (LVEF). Methods and Results: We studied 565 patients admitted for ADHF with survival discharge in our prospective cohort study. Laboratory data including free T 3 , thyroxine and TSH were obtained at discharge. Among the patients with euthyroid (0.35 μU/mL <TSH <4.94 μU/mL, n=438), there was 62 patients who were diagnoses as low T 3 syndrome (free T 3 ≦1.68 pg/mL). The primary end point of this study was all-cause death (ACD). During a mean follow up period of 2.9±1.4 years, 121 patients died. Study subjects were stratified into two LVEF subgroup as follows; 239 patients had LVEF<50% (HFrEF), and 199 patients had LVEF≧50% (HFpEF). While 68 HFrEF parients died, 53 HFpEF patients died. Kaplan-Meier curve analysis revealed that patients with the low free T 3 group had the greater risk of ACD than those with the normal free T 3 group in both LVEF subgroup (log-rank p=0.0233 in HFrEF and p=0.0265 in HFpEF). Multivariate Cox analysis showed that free T 3 was significantly associated with ACD after multivariable adjustment for major confounders, such as age, sex, systolic blood pressure and plasma brain natriuretic peptide level in both LVEF subgroup (p=0.0039 in HFrEF, p=0.0487 in HFpEF). Conclusion: Low T 3 syndrome was significantly associated with poor outcome in ADHF patients with both HFrEF and HFpEF.

Thyroid Disorders.

Thyroid Disorders.

Risk of over- and under- treatment with levothyroxine in primary care in Copenhagen, Denmark.

A decrease over time in thyroid stimulating hormone (TSH) levels when initiating levothyroxine (L-T4) therapy for hypothyroidism has been reported, where treatment most often is initiated with TSH levels below 10 mIU/L. The primary objective of this study was to investigate whether this lower TSH threshold resulted in an increased number of overtreated patients. Retrospective cohort study comprising inhabitants in Copenhagen had TSH measurements requested by general practitioners which led to a new prescription of L-T4 between 2001 and 2012. Over- and under- treatment were defined as TSH <0.1 mIU/L or above 10 mIU/mL, respectively, in three consecutive measurements. Data were analyzed by Aalen-Johansen estimators and Cox proportional hazards models. In total, 14 533 initiations of L-T4 were included in the study. The cumulative risk of being over- or undertreated was 4.7 and 7.4% after 10 years. The hazard of overtreatment was higher among women, younger adults, and with lower initial TSH levels. The hazard of overtreatment decreased over the time period from 2001 to 2012. Among overtreated individuals, the chance of returning to a normal TSH was about 55% after 10 years. In 18% of the cases, L-T4 therapy was initiated on TSH levels less than 5 mIU/L. Although a still decreasing threshold for initiating L-T4 therapy is known, the risk of overtreatment (and undertreatment) was low and lessened in the period 2001-2012 among Danish primary care patients. Nevertheless, as many as 18% were started on L-T4 with normal TSH levels.

Thyroid function and IVF outcome for different indications of subfertility.

Graphical Studies evaluating pregnancy outcomes after assisted reproductive treatment (ART) in women with high-normal (2.5–4.5 mIU/L) thyroid-stimulating hormone (TSH) levels are conflicting, possibly due to different patient charactistics and subfertility indications. The aim of this study was to examine the hypothesis that high-normal compared to low-normal TSH levels are associated with adverse implications for pregnancy outcomes in conventional in vitro fertilization (IVF)-treated women. Therefore, we analyzed retrospectively the characteristics and pregnancy outcomes of 949 subfertile women with TSH 0.3–4.5 mIU/L, treated with conventional IVF between January 2008 and March 2012. Demographic and baseline characteristics were compared between groups of patients based on TSH quartiles, using one-way Anova, Kruskal–Wallis ANOVA and chi-square test. Women with high-normal quartile TSH were significantly more likely to be primary subfertile (P = 0.01), with a higher prevalence of unexplained subfertility and with 15% fewer live births after IVF compared to lower TSH quartiles (P = 0.02). In secondary subfertile women with high-normal TSH, male factor subfertility prevailed (P = 0.01), with more live births (P = 0.01). When analyzing primary and secondary subfertile women as one group, these differences failed to be observed, showing no differences in cumulative pregnancy outcomes of IVF between TSH quartiles (I: 0.3–1.21 mIU/L; II: 1.22–1.68 mIU/L; III: 1.69–2.31 mIU/L; IV: 2.32–4.5 mIU/L). In conclusion, primary subfertile women predominate in the high-normal TSH quartile, associated with significantly fewer live births in a subgroup of primary unexplained subfertile women (9%; n = 87/949), while in secondary subfertile women, dominated by male factor subfertility, high-normal TSH is associated with more live births.Lay summaryThyroid hormones are required for all cell processes in the body. An underactive thyroid gland, in which insufficient thyroid hormones are produced and thyroid-stimulating hormone (TSH) rises, is associated with a lower chance of pregnancy. It is not yet clear above which TSH level, 4.5 or also 2.5 mIU/L, this lower probability occurs. Therefore, in 949 couples treated with conventional IVF, we examined whether high-normal TSH levels (TSH: 2.5–4.5 mIU/L) compared to low normal TSH levels (0.3–2.5 mIU/L) affect the live birth rate. We found that women who were trying to become pregnant for the first time, especially without any other cause, that is unexplained subfertility, were more likely to have higher TSH levels. These women had a much lower chance of having a baby compared to women with low-normal TSH levels.

The significance of the level of triiodothyronium in the diagnosis of the syndrome of “low triiodothyronine” in heart failure

Abstract Heart failure (HF) is an important issue in cardiology. Some patients with HF have the low T3 syndrome (LT3S). There is no consensus regarding the criteria for determining LT3S. The purpose is to study the features of LT3S determination in HF and its relationship with the disease course. Materials and methods A total of 157-patients with HF and postinfarction cardiosclerosis were examined. At the I stage, all patients were divided into 2 groups: I – 122 patients with normal level of free T3f, T4f and thyroid-stimulating hormone (TSH); II – 35 patients with LT3S (T3f≤2.5 pmol/l and normal levels of T4f and TSH). At the II stage, 129 patients without LT3S were included into group I and 28 patients with LT3S (T3f ≤2.07 pmol/l) – into group II. Serum levels of TSH, T3f, T4f, reverse T3 (T3r) were determined. Echocardiography was performed. HF course was studied during 2 years. Results The frequency of LT3S (T3f &amp;lt;2.5 pmol/l) among patients with HF is 22.3%. The risk of rehospitalization of patients according to ROC-analysis increases at the intersection of the point T3f ≤2.07 pmol/l (P=0.0017). At T3f ≤2.07 pmol/l the frequency of LT3S is 17.8%. Patients with LT3S (T3f ≤2.07 pmol/l) are younger (2.5 years younger; P=0.039), have larger end-diastolic size (by 4.8%; P=0.010) and volume (by 10.2%; P=0.012), end-systolic size (by 8.8%; P=0.003) and volume (by 20.1%; P=0.006), lower left ventricle (LV) ejection fraction (by 9.5%; P=0.033), than the patients without LT3S. The relative risk of rehospitalization in patients with LT3S (T3f ≤2.07 pmol/l) is 2.224 (P&amp;lt;0.05). Conclusions The frequency of LT3S (T3f &amp;lt;2.5 pmol/l) among patients with HF is 22.3% at level of T3f ≤2.07 pmol/l – 17.8%. The risk of rehospitalization in patients with HF increases at intersection of the point T3f ≤2.07 pmol/l. Patients with LT3S (T3f ≤2.07 pmol/l) are younger, have larger LV dilatation and lower ejection fraction, higher frequency of coronary intervention and rehospitalization risk than the patients without LT3S. Funding Acknowledgement Type of funding sources: None.

Association between thyroid-stimulating hormone (TSH) and proteinuria in relation to thyroid cyst in a euthyroid general population

BackgroundHigh normal levels of thyroid-stimulating hormone (TSH) have been reported to be associated with chronic kidney disease (CKD) among euthyroid individuals. However, there has been only limited research on the association between TSH and proteinuria, a major risk factor for the progression of renal disease.MethodsA cross-sectional study of 1595 euthyroid individuals was conducted. All participants were within the normal range for free triiodothyronine (T3), free thyroxine (T4), and TSH. Analyses were stratified by thyroid cyst status to test the hypothesis that the absence of thyroid cysts, an indicator of latent thyroid damage, is associated with declining ability to synthesis thyroid hormone.ResultsFor participants with thyroid cysts, a significant inverse association between TSH and proteinuria was observed (adjusted odds ratio (95% confidence intervals) of log-transformed TSH for proteinuria 0.40 (0.18, 0.89)). In participants without thyroid cysts, a significant positive association between those two factors was observed (2.06 (1.09, 3.90)).ConclusionsAmong euthyroid individuals in the general population, being in the normal range of TSH was found to have an ambivalent association with proteinuria. Thyroid cyst status could be an effect modifier for those associations.

Colorectal cancer causes alteration of thyroid hormone profile in newly diagnosed patients

ABSTRACT Objectives Subcellular alteration of thyroid hormones (THs) signaling is proposed in many types of cancers. Some studies show deiodinase type 3, as an oncofetal protein, re-expresses in some cancer types. Therefore, we aimed to investigate the product of this enzyme, reverse triiodothyronine (rT3) in serum of newly diagnosed colorectal cancer (CRC) patients. Methods In this cross-sectional study, blood from 38 laboratory-confirmed cases was taken, and serum levels of rT3, total T3 (triiodothyronine), total T4 (thyroxine), free T3, free T4, and thyroid-stimulating hormone (TSH) were detected by using an enzyme-linked immunosorbent assay. Results The results illustrated that rT3 and free T3 levels increased in patients with early stages of colorectal cancer, despite normal levels of total T3, total T4, free T4, and TSH. Conclusion The elevation of rT3 in CRC patients can probably be due to the re-expression of deiodinase type 3 in CRC. Further research is needed to study the role of intracellular THs modulation in CRC and its impact on CRC treatment.

Фактори кардіоваскулярного ризику у хворих на артеріальну гіпертензію при різному рівні тиреотропного гормону

Метою роботи було встановити вплив рівня тиреотропного гормону (ТТГ) на частоту і вираженість факторів кардіоваскулярного ризику у хворих на артеріальну гіпертензію (АГ). Були обстежені 123 хворі із АГ I–II ступенів віком 45–70 років. Методи дослідження: визначення показників ліпідограми, ТТГ, вільного тироксину, ехокардіографія, вимірювання офісного артеріального тиску (АТ), дуплексне сканування судин шиї, тестування за госпітальними шкалами тривоги і депресії. Серед обстежених хворих 12,4 % мали не діагностований раніше субклінічний гіпотиреоз, що асоціювався з більшою частотою дисліпідемії, порушення вуглеводного обміну, гіпертрофії лівого шлуночка і атеросклеротичного ураження сонних артерій, більш високими значеннями пульсового АТ, а також зі зменшенням швидкості клубочкової фільтрації і тривожно-депресивними розладами. При аналізі групи з нормальною функцією щитоподібної залози (ЩЗ) було виявлено, що високонормальний рівень ТТГ (2–4 мОд/л) також пов’язаний зі збільшенням частоти факторів кардіоваскулярного ризику і погіршенням стану органів-мішеней порівняно з особами із низьконормальним рівнем ТТГ. Отже, функціональний стан ЩЗ впливає на частоту та вираженість факторів ризику і уражень органів-мішеней при АГ, що потребує ретельного його контролю у хворих із кардіологічною патологією.

More Live Births in Primary Subfertile Intracytoplasmic Sperm Injection-Treated Women with High Normal TSH Levels

Objectives: The aim of this study was to analyze the fertility outcome in intracytoplasmic sperm injection (ICSI)-treated women across normal range thyroid-stimulating hormone (TSH) levels. Published results are inconclusive about optimal TSH levels and fertility. Design: This is a retrospective cohort study in 752 ICSI-treated women with predominantly severe male factor subfertility, starting treatment between the first of January 2008 and the first of March 2012 with a follow-up until 2014. Participants/Materials, Setting, Methods: Women aged 22–45 years with TSH 0.3–4.5 mIU/L without thyroid hormone substitution were included in Amsterdam UMC, Vrije Universiteit, Amsterdam, The Netherlands, an iodine-sufficient area. Demographic and baseline characteristics were compared between groups of patients based on TSH, using one-way ANOVA, Kruskal-Wallis ANOVA, and χ² test. The patient was the unit of analysis: all cumulative cycles per patient were analyzed up to and including the first ongoing pregnancy. The primary outcome was a cumulative live birth rate. Clinical pregnancy rate, pregnancy loss, and ongoing pregnancy rate were secondary outcomes. The χ² test and logistic regression were used to compare interquartile groups while adjusting for confounders. Logistic regression was used with the natural logarithm of TSH as a continuous predictor. Primary and secondary subfertile women were analyzed separately. Results: Analysis of the total cohort (n = 752) showed no difference in fertility outcomes across the normal TSH range. The cumulative live birth rate for the 4 groups of primary subfertile women (n = 455) was 76% in the upper TSH quartile compared to 56%, 60%, and 59% in the lower TSH quartiles. Limitations: Levels of thyroxine and presence of thyroid autoimmunity were not measured in this retrospective cohort study. Conclusions: The observation that a higher live birth rate was found in primary subfertile ICSI-treated women with high but allegedly normal TSH levels contributes to the hypothesis that in certain subfertile women in addition to a male factor, female factors such as subtle hypothyroidism and/or thyroid autoimmunity may play a role in keeping them from conception, which can be overcome by the process of ICSI.

Elevated thyroid-stimulating hormone levels are associated with poor sleep: a cross-sectional and longitudinal study.

Poor sleep accompanied by elevated TSH (thyroid stimulating hormone) levels is not uncommon since TSH secretion is controlled by the circadian rhythm. However, the relationship between poor sleep and TSH elevation is unclear; hence, we aimed to elucidate this relationship by conducting a cross-sectional and longitudinal study. Participants with isolated elevated (N = 168) and normal (N = 119) TSH concentrations were recruited, and the Pittsburgh Sleep Quality Index (PSQI) was used to assess the sleep status. Subjects with an isolated TSH elevation were followed up longitudinally. The serum TSH concentration was remeasured after sleep status improved. The proportions of poor sleep and occasional poor sleep in subjects with isolated TSH elevation were significantly higher than those with normal TSH levels (70.24% vs. 49.58%, p = 0.001; 9.52% vs. 1.68%, p = 0.006). Subjects with isolated TSH elevation had significantly higher PSQI scores in the subjective sleep quality, sleep latency, sleep duration, and habitual sleep efficiency dimensions than those with normal TSH levels (all p < 0.05). Poor sleep was significantly associated with isolated TSH elevation in the multiple logistic regression analysis [odds ratio (OR) = 2.396, p = 0.001]. Among subjects with an isolated TSH elevation at baseline, the percentage of TSH normalization was significantly higher in those who slept better than in those who still slept poorly (85.42% vs. 6.45%, p < 0.001). This study revealed that isolated elevated TSH concentrations normalize when the sleep status is improved; hence, we recommend that clinicians thoroughly assess the sleep status of patients and remeasure TSH concentrations after sleep status improves.

The factors associated with transient hypothyroxinemia of prematurity

BackgroundHypothyroxinemia is defined by low levels of thyroxine (T4) despite low or normal levels of thyroid-stimulating hormone (TSH). This study aimed to evaluate the factors associated with transient hypothyroxinemia of prematurity (THOP) in newborns admitted to the neonatal intensive care unit (NICU).MethodThis is a single center, retrospective, case-control study. Premature newborns, between 24 and 34 weeks of gestation, hospitalised between January 2014–December 2019 in Istanbul University-Cerrahpasa Faculty of Medicine NICU were analyzed through their medical records. Thyroid function tests were routinely performed between the 10th and 20th days of postnatal life and were evaluated according to the gestational age references. Thirty six possible associated factors (prenatal and postnatal parameters, medical treatments, clinical diagnoses and applications in NICU) were searched in the patient group with THOP (n = 71) and the control group with euthyroid prematures (n = 73). The factors for THOP were identified by univariate analysis, followed by multivariate analysis.ResultsMean gestational ages of the study and the control groups were 29.7 ± 2.48 and 30.5 ± 2.30 weeks, respectively (p = 0.606). The birth weight, small for gestational age (SGA), intraventricular hemorrhage (IVH), congenital heart disease (CHD) were found to be the possible associated factors for THOP in the univariate analysis and CHD (p = 0.007, odds ratio [OR]:4.9, 95% confidence interval [CI]: 1.5–15.8), BW (p = 0.004, OR:0.999, 95% CI: 0.9–1.0) and SGA (p = 0.010, OR:4.6, 95% CI: 1.4–14.7) were found to be factors associated with THOP determined by univariate logistic regression analysis.ConclusıonsAlthough some treatment practices might have had direct effects on pituitary–thyroid axis, related with the severity of the newborn clinical conditions, non of them was found to be a associated factor for THOP. However, CHD and SGA may be considered as associated factors with THOP detected in preterm infants.

MEANS TO OPTIMIZE THE TREATMENT OF DYSLIPIDEMIA IN PATIENTS WITH HYPOTHYROIDISM

In order to study the peculiarities of lipid metabolism and atorvastatin efficacy for patients with hypothyroidism, it was examined 133 patients with manifested hypothyroidism. It was revealed malfunction lipid metabolism, i. e. a direct correlation between total cholesterol levels and thyroidstimulating hormone (TSH). It was confirmed, that higher indices of dyslipidemia are associated with the most manifested abdominal obesity and with higher body mass index. Reaching of normal levels of thyroid-stimulating hormone during hormone-replacing therapy is not sufficient to gain the required levels of major indices in lipid profile. It was proved efficacy of atorvastatin in complex treatment of hypothyroidism.

26966 Tofacitinib treats unresponsive vitiligo and elevated thyroid peroxidase antibodies

A 56-year-old female presented with expanding vitiligo to 35% total body surface area (TBSA) despite treatment with alpha lipoic acid, vitamin C, vitamin E, polypodium leucotomus, topical pimecrolimus, narrowband ultraviolet B, and excimer laser for 2 months. Past medical history was pertinent for Hashimoto thyroiditis treated with levothyroxine with normal levels of thyroid stimulating hormone (TSH) and free thyroxine (FT4), psoriatic arthritis, alopecia, and localized psoriasis on the elbows. Notably, lab tests confirmed normal levels of serum TSH and FT4 but elevated thyroid peroxidase antibodies (TPO) of 795 and elevated thyroglobulin antibodies (TG) of 3. Her endocrinologist denied necessity of treating patients for elevated TPO but stated that patients were only treated with increased dosages of levothyroxine. Because of reported case reports of success in treating vitiligo and FDA-approval for psoriatic arthritis, tofacitinib 5 mg (Tofa) twice daily (BID) was added to the treatment regimen. Serum levels of TPO and TG normalized within 1 month, with simultaneous improvement in vitiligo. Because of gastrointestinal side effects after BID dosing for 5 months, Tofa was decreased to once daily, with continued vitiligo repigmentation. By then, vitiligo had decreased to 12% TBSA, with accompanying improvement in alopecia, psoriatic arthritis, and psoriasis. This case suggests that unstable vitiligo may be associated with elevated TPO and TG, because of a disregard of endocrinologists to treat elevated antibodies, and should be tested in patients with unresponsive vitiligo. Tofacitinib may ameliorate vitiligo not only as a Janus kinase inhibitor but also through an effect on TPO and TG.

Overtreatment of Transient Maternal Hyperthyroidism Resulting in Fetal Goiter.

Overtreatment of Transient Maternal Hyperthyroidism Resulting in Fetal Goiter.

Appropriate dose of levothyroxine replacement therapy for hypothyroid obese patients

BackgroundAthyreotic patients require a daily levothyroxine (LT4) doses of 1.6–1.8 mcg/kg of actual body weight (BW) to achieve normal thyroid stimulating hormone (TSH) levels. Lean body mass (LBM) calculation may be a more accurate determination of LT4 dose in obese patients. Previous studies were mainly investigated in Caucasians and LBM is markedly different between various ethnic groups. We aim to identify the optimal dose of LT4 replacement therapy in hypothyroid Thai patients including obese subjects. MethodsWe retrospectively reviewed the medical records of Thai adults with hypothyroidism at the thyroid clinic. Patients had been received LT4 (Brand: Euthyrox) at a stable dose ≥ 75 mcg/day for at least 1 year. Patients with thyroid cancer, pregnant, and lactating women were excluded. LBM was calculated by the Hume formula. ResultsTwo hundred patients (80% females) with a mean age of 48.6 ± 14.8 years and a body mass index (BMI) of 24.5 ± 4.6 kg/m2 were included. Daily LT4 dose/kg of actual BW according to BMI 18.5–24.9, 25–29.9, and ≥ 30 kg/m2 were 1.67 ± 0.27, 1.51 ± 0.28 and 1.39 ± 0.34 mcg/kg, respectively. In contrast, LT4 dose/kg of LBM were 2.31 ± 0.39, 2.35 ± 0.45 and 2.36 ± 0.51 mcg/kg, respectively. ConclusionsLBM is considered a better indicator for calculating an appropriate LT4 replacement dose than actual BW in hypothyroid obese Thai patients. The recommended daily dose of LT4 is 2.3 mcg/kg of LBM that could be applied for all ranges of BMI.

English

BACKGROUND The importance of adequate iodine status in pregnancy is undoubted as its deficiency is associated with adverse pregnancy outcomes for the mother as well as the foetus and neonate. Although median urine iodine concentration can assess iodine status of the population but not at an individual level. The purpose of this study was to assess the nutritional status of iodine and identify its effects on thyroid function during the first trimester of pregnancy. METHODS The study was carried out on 341 euthyroid healthy pregnant women using urine iodine concentration and other parameters of thyroid panel at a tertiary care hospital. RESULTS Median (interquartile range) urine iodine concentration and thyroid stimulating hormone (TSH) were 227.37 (161.7, 343.86) μg / L and 1.8 (1.1, 2.7) mIU / L respectively and Mean ± SD of free thyroxine and thyroid peroxidase antibodies were 14.53 ± 2.02 pmol / L and 38.23 ± 9.29 kIU / L respectively. Only thyroid peroxidase antibodies showed significant difference across groups with different iodine status. A positive correlation of urine iodine concentration (UIC) with thyroid peroxidase antibodies was observed (r = 0.137, P = 0.011). Multiple regression analysis revealed that thyroid peroxidase antibodies can serve as an independent predictor of iodine status in the presence of normal levels of TSH and FT4 (t - 3.063, CI; 0.880, 4.038, P = 0.002). CONCLUSIONS Thyroid peroxidase antibodies progressed positively with increase in urine iodine concentration indicating its role as a marker of iodine nutritional status and for early identification of women who can develop autoimmune thyroiditis resulting in hypothyroidism even prior to elevation of thyroid stimulating hormone levels. KEY WORDS Anti-TPO Ab, Free Thyroxine, Thyroid Stimulating Hormone, Urine Iodine Concentration

A Galvanizing Solution: Colonoscopy Bowel Preparation as a Trigger for Supraventricular Tachycardia.

Polyethylene glycol (PEG)-based solutions are among the most commonly used bowel preparation regimens for colonoscopy. Although these solutions are well tolerated, rare adverse cardiac events have been reported. We sought to identify the characteristics that may predispose patients to develop supraventricular tachycardia (SVT) after ingestion of GoLYTELY (PEG 3350 and electrolytes oral solution) in anticipation for their colonoscopy. We performed a retrospective observational cohort study of the electronic medical record of all patients who developed SVT after ingestion of GoLYTELY solution from April 2012 to March 2019 at the John D. Dingell VA Medical Center. Clinical data were obtained through review of medical records. We identified 16 patients with new-onset SVT after ingestion of bowel preparation solution before undergoing the colonoscopy procedure. In all, 12 (75%) patients developed atrial fibrillation, 3 (18.8%) patients developed atrial tachycardia, and 1 patient (6.3%) developed atrial flutter. Most patients were male (93.8%), and the mean age was 69 ± 8.2 years. The commonly associated comorbidities were hypertension (87.5%), hyperlipidemia (56.3%), and diabetes (37.5%). Laboratory testing demonstrated a normal electrolyte panel and thyroid stimulating hormone level. A significant percentage of patients had dilated atria and left-ventricular hypertrophy on echocardiogram. Our case series suggests that there may be certain individuals who are predisposed to development of atrial arrhythmias, more so than others, after ingestion of PEG based solution for colonoscopy. We hypothesize that the combination of atrial dilation, sympathovagal discharge, and transient electrolyte shifts at the cellular level led to the development of SVTs.

PND53 Predictive Models Leveraging Machine Learning and Real-World Data for Early Diagnosis: An Application in Amyotrophic Lateral Sclerosis

To assess the utility of machine learning for predicting early diagnosis of amyotrophic lateral sclerosis (ALS) based on real-world data (RWD). We identified 4779 patients with ALS and without primary lateral sclerosis from the Optum® de-identified Electronic Health Record (EHR) dataset (2007-2020), and 47,781 patients as the control cohort who did not have ALS and were demographically matched by age and gender in a 1:10 target to control ratio. Mutual information was used to explore and identify features in RWD, including lab, microbiology, and natural language processing biomarkers available in EHR, by comparing the target population (ALS patients) with the demographically matched control cohort. We trained various machine learning models (eg, logistic regression, random forest, gradient boosting, support vector machines, neural networks, soft voting) spanning different periods of time relative to a defined index date and compared their performance in predicting early diagnosis of ALS. Predictive models trained with gradient boosting on data closer to the defined index date, including lab tests from EHR, performed the best and had a very low false positive rate (AUC=0.9463). This model suggested that the top 5 predictors of an undiagnosed ALS patient were muscle weakness (generalized), normal thyroid stimulating hormone levels, dysphagia (unspecified), cramp of limb/abnormal involuntary movements, and other musculoskeletal symptoms referable to limbs. Many of the features were diagnoses that could be considered for an earlier evaluation of ALS in clinical practice. Indeed, the model had a sensitivity of 1%, specificity >99.0%, and was able to identify with a precision of 63% patients not yet identified with ALS, suggesting that early screening for ALS would be beneficial. This study highlights opportunities of leveraging machine learning utilizing EHR RWD to identify features that predict early diagnosis of ALS.