Thyroid Dysfunction and Anemia: A Prospective Cohort Study and a Systematic Review

Development, Validation and Clinical Utility of a Risk Prediction Model for Maternal and Neonatal Adverse Outcomes in Pregnant Women with Hypothyroidism

Purpose

This study aimed to create, verify and assess the clinical utility of a prediction model for maternal and neonatal adverse outcomes in pregnant women with hypothyroidism.

Methods

A prediction model was developed, and its accuracy was tested using data from a retrospective cohort. The study focused exclusively on female patients diagnosed with hypothyroidism who were admitted to a tertiary hospital. The development and validation cohort comprised individuals who gave birth between 1 October 2020 and 31 December 2022. The primary outcome was a combination of crucial maternal and newborn problems (eg premature births, abortions and neonatal asphyxia). The prediction model was developed using logistic regression. Evaluation of the model's performance was conducted based on its ability to discriminate, calibrate and provide clinical value.

Results

In total, nine variables were chosen to develop the predictive model for adverse maternal and neonatal outcomes during pregnancy with hypothyroidism. The area under the curve of the model for predicting maternal adverse outcomes was 0.845, and that for predicting neonatal adverse outcomes was 0.685. The calibration plots showed good agreement between the nomogram predictions and the actual observations in both the training and validation cohorts. Furthermore, decision curve analysis suggested that the nomograms were clinically useful and had good discriminative power to identify high-risk mother-infant cases.

Conclusion

Two models to predict the risk probability of maternal and neonatal adverse outcomes in pregnant women with hypothyroidism were developed and verified to assist physicians in evaluating maternal and neonatal adverse outcomes throughout pregnancy with hypothyroidism and to facilitate decision-making regarding therapy.

Frequency and Types of Anemia in Primary Hypothyroidism Patients: A Prospective Observational Study

Background Primary hypothyroidism is a common endocrine disorder resulting from inadequate production of thyroid hormones. Anemia is a common condition that can occur in hypothyroidism. Anemia may occur due to nutrient deficiency, such as iron or vitamin B12 deficiency due to chronic disease in hypothyroidism. Therefore, it is important to evaluate the cause of anemia in hypothyroidism.  Objective The aim of this study was to determine the frequency of anemia and its types in patients with primary hypothyroidism. Methods This was a prospective cross-sectional observational study conducted at the Department of Medicine, Jinnah Postgraduate Medical Center, Karachi, Pakistan, using non-probability consecutive sampling. A total of 176 adults aged 18-65 years of either gender, newly diagnosed with primary hypothyroidism, or with any of its symptoms were included in the study. Patients already on anti-thyroid medication and with post-thyroidectomy hypothyroidism were excluded from the study. The duration of the study was 1.5 years, from January 2020 to July 2021. After ethical approval, written informed consent was obtained from each patient. Demographical data along with results of complete blood picture, including Hb and MCV for diagnosing anemia and its types were recorded on a pre-designed proforma. The chi-square test was applied keeping p < 0.05 as statistically significant. Results The mean age of the patients was 42.19 ± 8.43 years, with 59.66% (n = 105) females and 40.34% (n = 71) males. A total of 67% (n =118) patients were found to be anemic. Of these, 38.64% (n = 68) patients had normocytic anemia, 19.32% (n = 34) microcytic anemia, and 9.25% (n = 16) patients had macrocytic anemia; 56.34% (n = 40) males and 74.29% (n = 78) females were reported to be anemic (p = 0.01). Conclusion In our study, the frequency of anemia in patients with hypothyroidism was high, with normocytic anemia being the most common type. It is important to know the type of anemia in hypothyroidism, as normocytic anemia is due to the chronic disease process (anemia of chronic disease) and may not respond to nutrient supplementation. Conversely, microcytic anemia is commonly due to iron deficiency and macrocytic anemia is due to vitamin B12 deficiency and therefore, they require replacement therapy. In any case, it is important to identify and treat the underlying cause of anemia.

Higher serum free thyroxine levels are associated with increased risk of hip fractures in older men

Overt and subclinical hyperthyroidism are associated with an increased fracture risk, but whether thyroid hormones are associated with fracture risk in individuals with normal thyroid-stimulating hormone (TSH) has mostly been investigated in women. Therefore, we investigated if serum levels of free thyroxine (FT4) or TSH are associated with fracture risk in Swedish men. We followed (median 12.2 yr) elderly men (n = 1825; mean age 75, range 69-81 yr) participating in the Gothenburg and Malmö subcohorts of the prospective, population-based MrOS-Sweden study. The statistical analyses included Cox proportional hazards regression. Men receiving levothyroxine treatment were excluded. In our total cohort, serum FT4 (per SD increase) was associated with increased risk of major osteoporotic fractures (MOFs; n = 479; fully adjusted hazard ratio [HR] 1.14, 95% CI, 1.05-1.24) and hip fractures (n = 207; HR 1.18, 95% CI, 1.04-1.33). Also, in men with normal TSH (n = 1658), FT4 (per SD increase) was significantly associated with increased risk of MOF and hip fractures. Furthermore, men in the highest FT4 quartile had a 1.5-fold increase in hip fracture risk compared with men in the three lower FT4 quartiles, both in the total population and in men with normal TSH (fully adjusted: HR 1.45, 95% CI, 1.04-2.02 and HR 1.51, 95% CI, 1.07-2.12, respectively). In contrast, the risk of MOF was not statistically different in the highest FT4 quartile compared with the three lower FT4 quartiles. Finally, serum TSH was not associated with fracture risk after full adjustment for covariates. In conclusion, serum FT4, but not serum TSH, is a predictor of hip fracture risk in elderly Swedish men. Additionally, there was an association between FT4 (per SD increase) and the risk of MOF.

Thyroid Hormones and Cardiometabolic Risk Factors in Saudi Women with Polycystic Ovary Syndrome: A Cross-Sectional Study

Objective

The PCOS-thyroid nexus has recently drawn the focus of various investigations due to the prevalence of thyroid problems in PCOS. Additionally, risk factors for cardiovascular disease (CVD) are more prevalent in PCOS women. Therefore, we aim to assess the levels of thyroid hormones in Saudi females with polycystic ovary syndrome (PCOS) and to examine the correlation between cardiometabolic risk factors (CMRFs) and thyroid hormones in PCOS patients.

Methods

A cross-sectional research with 200 PCOS-diagnosed female patients was conducted from April 2018 to April 2020. In addition to other anthropometric and serum biochemical markers, glycemic status, thyroid function test, lipid profiles, homocysteine, and C-reactive protein levels were detected in patients.

Results

In PCOS, hypothyroidism is more common than hyperthyroidism (55 vs 27.5%, p = 0.05). While women with raised TSH (hypothyroidism) had a higher BMI, WC, FBG, and poorer HDL-C (p< 0.05). Significant differences were found in LDL-C, TG, Homocysteine, and CRP levels (all p<0.001 and< 0.05). PCOS women with hypothyroidism at increased risk of CVD, as indicated by AIP (Atherogenic Index of plasma) (0.57±0.42) was found. The elevated TSH levels were favorably linked with TG, Homocysteine, CRP, BMI, AIP, and WC (all p< 0.001, 0.05) but negatively connected with HDL-C and FT4.

Conclusion

A strong relationship between PCOS and thyroid dysfunction was detected since PCOS hypothyroid groups had higher TSH levels and CMRFs. This group's CVD risk was elevated due to CRP, homocysteine, triglycerides, and obesity.

No Effect of Levothyroxine on Hemoglobin in Older Adults With Subclinical Hypothyroidism: Pooled Results From 2 Randomized Controlled Trials

CONTEXT

Subclinical thyroid dysfunction and anemia are common disorders, and both have increasing prevalence with advancing age.

OBJECTIVE

The aim of this study was to assess whether levothyroxine treatment leads to a rise in hemoglobin levels in older persons with subclinical hypothyroidism.

METHODS

This preplanned combined analysis of 2 randomized controlled trials included community-dwelling persons aged 65 years and older with subclinical hypothyroidism who were randomly assigned to levothyroxine or placebo treatment. The levothyroxine dose was periodically titrated aiming at thyroid stimulating hormone (TSH) level within the reference range, with mock titrations in the placebo group. The main outcome measure was the change in hemoglobin level after 12 months.

RESULTS

Analyses included 669 participants (placebo n = 337, levothyroxine n = 332) with a median age of 75 years (range, 65-97) and mean baseline hemoglobin of 13.8 ± 1.3 g/dL. Although levothyroxine treatment resulted in a reduction in TSH from baseline after 12 months of follow-up compared with placebo, the change in hemoglobin level was not different between the levothyroxine and the placebo groups (-0.03 g/dL [95% CI, -0.16 to 0.11]). Similar results were found in stratified analyses including sex, age, or TSH levels. No difference in change of hemoglobin levels after 12 months was identified in 69 participants with anemia at baseline (-0.33 g/dL [95% CI, -0.87 to 0.21]).

CONCLUSION

In persons aged 65 years and older with subclinical hypothyroidism, treatment with levothyroxine does not lead to a rise in hemoglobin levels, regardless of the presence of anemia.

Thyroid Function and Risk of Anemia: A Multivariable-Adjusted and Mendelian Randomization Analysis in the UK Biobank

CONTEXT

Thyroid dysfunction is associated with higher anemia prevalence, although causality remains unclear.

OBJECTIVE

This study aimed to investigate the association between thyroid function and anemia.

METHODS

This cross-sectional and Mendelian randomization study included 445 482 European participants from the UK Biobank (mean age 56.77 years (SD 8.0); and 54.2% women). Self-reported clinical diagnosis of hypothyroidism was stated by 21 860 (4.9%); self-reported clinical diagnosis of hyperthyroidism by 3431 (0.8%). Anemia, defined as hemoglobin level of < 13 g/dL in men and < 12 g/dL in women, was present in 18 717 (4.2%) participants.

RESULTS

In cross-sectional logistic regression analyses, self-reported clinical diagnoses of hypo- and hyperthyroidism were associated with higher odds of anemia (OR 1.12; 95% CI, 1.05-1.19 and OR 1.09; 95% CI, 0.91-1.30), although with wide confidence intervals for hyperthyroidism. We did not observe an association of higher or lower genetically influenced thyrotropin (TSH) with anemia (vs middle tertile: OR for lowest tertile 0.98 [95% CI, 0.95-1.02]; highest tertile 1.02 [95% CI, 0.98-1.06]), nor of genetically influenced free thyroxine (fT4) with anemia. Individuals with genetic variants in the DIO3OS gene implicated in intracellular regulation of thyroid hormones had a higher anemia risk (OR 1.05; 95% CI, 1.02-1.10); no association was observed with variants in DIO1 or DIO2 genes.

CONCLUSION

While self-reported clinical diagnosis of hypothyroidism was associated with higher anemia risk, we did not find evidence supporting a causal association with variation of thyroid function within the euthyroid range. However, intracellular regulation of thyroid hormones might play a role in developing anemia.

Subclinical hyperthyroidism is associated with increased risk of vertebral fractures in older men

In elderly men included in MrOS-Sweden, subclinical hyperthyroidism (SHyper) was markedly associated with increased risk of vertebral fractures.

INTRODUCTION

Overt hyperthyroidism is associated with increased risk of fractures. However, only a few studies have investigated whether SHyper is associated with fracture risk in elderly men. We therefore investigated if SHyper was a risk factor for fractures in Swedish men.

METHODS

We followed (median 9.8 years) elderly men (n = 1856; mean age 75, range 69-81 years) participating in the Gothenburg and Malmö subcohorts of the prospective, population-based MrOS-Sweden study. The statistical analyses included Cox proportional hazards regression. SHyper was defined as serum thyroid-stimulating hormone (TSH) < 0.45 mIU/L (n = 38).

RESULTS

SHyper was associated with increased risk of all fractures [n = 456; hazard ratio (HR) adjusted for age, study center, and levothyroxine treatment = 1.99, 95% confidence interval (CI): 1.20-3.32], major osteoporotic fractures (MOF, n = 338; HR 2.44, 95% CI: 1.42-4.21), and vertebral fractures (n = 176; HR 3.79, 95% CI: 2.02-7.11). These associations remained after full adjustment for covariates including total hip bone mineral density and in subanalyses including only men with serum free thyroxine ≤ the upper normal limit. However, after exclusion of men receiving levothyroxine treatment, the associations with all fractures and MOF lost significance.

CONCLUSIONS

In elderly Swedish men, there was a strong association between SHyper and increased risk of vertebral fractures, whereas the associations with all incident fractures and MOF need to be confirmed in further studies.

Association Between Red Blood Cell Distribution Width and Thyroid Function

AIM

Red blood cell distribution width (RDW) is an important parameter with broad biological implications. However, the study investigating the association between RDW and thyroid function remains sparse and inconsistent. We aimed to investigate the association between RDW and thyroid function in the US population.

METHODS

A cross-sectional analysis was performed using the data from the National Health and Nutrition Examination Survey (NHANES) conducted from 2007 to 2010. The thyroid parameters investigated were mainly free triiodothyronine (fT3), free thyroxine (fT4), thyroid-stimulating hormone (TSH), antithyroglobulin antibody (TgAb), and antithyroperoxidase antibody (TPOAb). In the 6,895 adults aged 18 years or older, logistic regression modeling was applied to estimate the association between RDW quartiles and thyroid parameters. Smooth curve fittings and generalized additive models were then performed to address the nonlinear relationship.

RESULTS

The association between RDW and TSH followed a J-shaped curve, and a significant positive relationship existed in the 12.5%-17.5% range of RDW (β  = 0.350, 95% confidence interval (CI): 0.225 to 0.474), which was prominent in females. We further demonstrated a negative association (β = -0.018, 95% CI: -0.030 to -0.005) between RDW and fT3. Moreover, elevated RDW was more likely to be subclinical hypothyroidism. However, there was no obvious association between RDW and fT4.

CONCLUSION

This study confirmed a significant association between RDW and TSH, and future studies are needed to elucidate the underlying mechanisms of the peculiar RDW-fT3 relationship. RDW may be a significant clinical marker of subclinical hypothyroidism.

Comorbidity patterns among people living with HIV: a hierarchical clustering approach through integrated electronic health records data in South Carolina

Comorbidity among people living with HIV (PLWH) is understudied although identifying its patterns and socio-demographic predictors would be beneficial for comorbidity management. Using electronic health records (EHR) data, 8,490 PLWH diagnosed between January 2005 and December 2016 in South Carolina were included in the current study. An initial list of 86 individual diagnoses of chronic conditions was extracted in the EHR data. After grouping individual diagnoses with a pathophysiological similarity, 24 diagnosis groups were generated. Hierarchical cluster analysis was applied to these 24 diagnosis groups and yielded four comorbidity clusters: "substance use and mental disorder" (e.g., alcohol use, depression, and illicit drug use); "metabolic disorder" (e.g., hypothyroidism, diabetes, hypertension, and chronic kidney disease); "liver disease and cancer" (e.g., hepatitis B, chronic liver disease, and non-AIDS defining cancers); and "cerebrovascular disease" (e.g., stroke and dementia). Multivariable logistic regression was conducted to investigate the association between socio-demographic factors and multimorbidity (defined as concurrence of ≥ 2 comorbidity clusters). The multivariable logistic regression showed that age, gender, transmission risk, race, initial CD4 counts, and viral load were significant factors associated with multimorbidity. The results suggested the importance of integrated clinical care that addresses the complexities of multiple, and potentially interacting comorbidities among PLWH.

Effects of thyroid dysfunction on hematological parameters: Case controlled study

Introduction

The thyroid gland has a very important role in hematopoiesis, blood disorders are frequently seen in patients with thyroid disorders. Thyroid hormones have direct effect on blood parameters by stimulating erythrocytes precursors and indirectly by enhancing erythropoietin production.

Patients and methods

This is a case-control study which included 300 subjects who were grouped to 3 equal groups as a control, hypothyroidism, and hyperthyroidism groups. Patients with inherited or acquired red cell abnormalities, those receiving treatment for thyroid disorder or anemia, patient with chronic diseases, aged <12 years, pregnant ladies and patients unwilling to participate in the study were excluded.

Results

The mean age of patients is 40.72 years, and females constituted 60.7% of cases. The analyses showed a significant difference the RBC, HB, MCV, MCHC, RDW, and WBC (P values 0.000, 0.000, 0.001, 0.012.0.002, and 0.027) respectively, while platelets showed no significant correlation (P value 0.08). The univariate analyses showed that RBC, the HB, and the WBC were the most severely affected parameters (Sig. 0.000, 0.000, and 0.005) respectively.

Conclusion

The study concluded that females are more affected by thyroid disorders than males and the peak age is at the forties, thyroid dysfunction affect all blood parameters except platelets.The follow up of patients with thyroid disorders should include the complete blood count and patients diagnosed with anemia should be evaluated for thyroid disorders before iron therapy. Cases of anemia that resist treatment should be investigated for the possibility of thyroid dysfunction.

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The thyroid gland has a very important role in hematopoiesis.

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Females are more affected by thyroid disorders than males.

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Thyroid hormones directly stimulate erythrocytes precursors and indirectly by enhancing erythropoietin production.

Changes in serum hepcidin according to thyrometabolic status in patients with Graves' disease

INTRODUCTION

Hepcidin is an acute-phase protein and a key regulator of iron homeostasis. Anaemia frequently occurs in patients with thyroid dysfunction, and hepcidin may be a potential link.

OBJECTIVES

Prospective assessment of hepcidin serum concentration and other parameters related to Fe homeostasis in hyperthyroid patients in the course of GD at diagnosis and during remission.

PATIENTS AND METHODS

Out of 70 patients recruited, 42 (32 women, 10 men), aged 42.5±15.1 years, met the inclusion criteria. Clinical and biochemical assessment, including hepcidin measurement by ELISA, was performed at baseline (T0) and after restoration of euthyroidism (T1).

RESULTS

Hepcidin concentration at T0 in the 24 patients who completed the study was significantly higher than the value during euthyroidism (28.7 (8.1-39.4) ng/mL vs. 7.9 (4.3-12.9) ng/mL, p<0.001). Hepcidin level was most significantly correlated with ferritin (rho = 0.723) in women at T0. In both men (377 (171-411) vs. 165 (84-237) ng/mL, p=0.001) and women (84 (23-104) vs. 35 (16-64) ng/mL, p=0.001), a significant decrease in ferritin level was demonstrated following therapy. A significant (p<0.001) increase in mean corpuscular volume (MCV) (83.5 (82.5-87.1) vs. 89.5 (88.8-90.0) fL) and mean concentration of haemoglobin (MCH) (29.0 (28.0-29.4) vs. 30.4 (29.5-31.1) pg) was observed.

CONCLUSIONS

Hepcidin and ferritin decrease significantly during the transition from a hyperthyroid state to euthyroidism in patients with GD. The observed changes occur in parallel to iron homeostasis fluctuations. During the transition from the hyperthyroid state to euthyroidism, the improvement of haematological status is reflected mainly by the increase in MCV and MCH.

Clinical and Biochemical Characteristics of Severe Hypothyroidism Due to Autoimmune Thyroiditis in Children

Introduction: In the majority of countries, autoimmune thyroiditis is the main cause of acquired hypothyroidism in children. Typically, the natural course of the disease is initially insidious and the diagnosis is incidental. There are some children who develop severe hypothyroidism without a proper diagnosis. The aim of the study was to analyze the clinical and biochemical profiles of children with severe primary hypothyroidism due to autoimmune thyroiditis. Materials and Methods: We analyzed the records of 354 patients diagnosed between 2009 and 2019 with autoimmune thyroiditis. Only patients with TSH above 100 μIU/mL, associated with decreased free thyroxine and the presence of antithyroid antibodies, were enrolled in the study. The analysis encompassed clinical symptoms, thyroid and biochemical status, bone age, and imaging. Results: Twenty-six children were enrolled in the study. The mean age at diagnosis was 10.26 ± 3.3 years, with a female preponderance of 1.8:1. The most frequent symptom was growth impairment (77%) and weight gain (58%). Goiters were present in 42% of patients. Less common findings were pituitary hypertrophy (four patients) and hypertrichosis (three patients). Median values at the time of diagnosis were TSH 454.3 uIU/ml (295.0-879.4), anti-TPO antibodies 1,090 IU/ml, and anti-Tg antibodies 195 IU/ml. Anti-TSHR ab were evaluated only in six out of the 26 patients. The characteristic biochemical profile was correlated with the grade of hypothyroidism, and the strongest correlations were found with CBC parameters, lipid profile, aminotransferases, and creatine. Conclusion: In children with severe hypothyroidism, the most sensitive symptoms are growth arrest and weight gain despite the fact that, in some children, the auxological parameters at presentation could be within normal values for the population. The specific biochemical profile closely correlates to the severity of thyroid hormone deficiency and involves mostly erythropoiesis, liver function, and kidney function. Pituitary enlargement should be considered in each child with severe hypothyroidism. It is necessary to conduct prospective studies evaluating the actual frequency of anti-TSHR antibodies and pituitary enlargement in children with extremely high TSH, especially those presenting without goiters.

Low-Normal Thyroid Function Predicts Incident Anemia in the General Population With Euthyroid Status

CONTEXT

Thyroid hormones (THs) have direct and indirect effects on hematopoiesis. However, few studies have directly evaluated the effect of THs on incident anemia among euthyroid subjects. This cohort study aimed to explore whether THs under physiological conditions can affect the development of anemia in the general population.

DESIGN

A total of 12,310 participants were enrolled in the cohort study (∼5-year follow-up period; mean, 3.1 years). A chemiluminescence immunoassay was used to measure free T3 (FT3), free T4 (FT4), and TSH, and anemia was defined according to the World Health Organization recommendation. THs, TSH, and Hb were assessed yearly during follow-up. Multivariable Cox proportional hazards regression models were used to assess the association between THs, TSH, and incident anemia.

RESULTS

The fully adjusted hazards ratios (95% CI) of anemia per 1-unit change in FT3, FT4, and TSH concentrations were 0.70 (0.56, 0.87), 0.93 (0.88, 0.98), and 1.19 (0.94, 1.50) (P < 0.01, P < 0.01, and P = 0.14, respectively). Moreover, a significant and positive association between FT3, FT4, and annual changes in Hb (standard regression coefficients of 0.056 and 0.028, respectively; both P < 0.01) was observed. Similar associations were observed when the participants who had thyroid dysfunction upon follow-up were excluded.

CONCLUSIONS

The current study demonstrated that THs significantly predict future anemia and annual changes in Hb, even in the euthyroid population.

The Relation Between Thyroid Function and Anemia: A Pooled Analysis of Individual Participant Data

Context

Anemia and thyroid dysfunction often co-occur, and both increase with age. Human data on relationships between thyroid disease and anemia are scarce.

Objective

To investigate the cross-sectional and longitudinal associations between clinical thyroid status and anemia.

Design

Individual participant data meta-analysis.

Setting

Sixteen cohorts participating in the Thyroid Studies Collaboration (n = 42,162).

Main Outcome Measures

Primary outcome measure was anemia (hemoglobin <130 g/L in men and <120 g/L in women).

Results

Cross-sectionally, participants with abnormal thyroid status had an increased risk of having anemia compared with euthyroid participants [overt hypothyroidism, pooled OR 1.84 (95% CI 1.35 to 2.50), subclinical hypothyroidism 1.21 (1.02 to 1.43), subclinical hyperthyroidism 1.27 (1.03 to 1.57), and overt hyperthyroidism 1.69 (1.00 to 2.87)]. Hemoglobin levels were lower in all groups compared with participants with euthyroidism. In the longitudinal analyses (n = 25,466 from 14 cohorts), the pooled hazard ratio for the risk of development of anemia was 1.38 (95% CI 0.86 to 2.20) for overt hypothyroidism, 1.18 (1.00 to 1.38) for subclinical hypothyroidism, 1.15 (0.94 to 1.42) for subclinical hyperthyroidism, and 1.47 (0.91 to 2.38) for overt hyperthyroidism. Sensitivity analyses excluding thyroid medication or high levels of C-reactive protein yielded similar results. No differences in mean annual change in hemoglobin levels were observed between the thyroid hormone status groups.

Conclusion

Higher odds of having anemia were observed in participants with both hypothyroid function and hyperthyroid function. In addition, reduced thyroid function at baseline showed a trend of increased risk of developing anemia during follow-up. It remains to be assessed in a randomized controlled trial whether treatment is effective in reducing anemia.