Thyroid functional disease: an under-recognized cardiovascular risk factor in kidney disease patients

Association of thyroid hormones with the severity of chronic kidney disease: a cross-sectional observational study at Tabuk, Saudi Arabia

Background

The interplay between chronic kidney disease (CKD) and thyroid dysfunction is becoming more evident in the biomedical community. However, the intricacies of their relationship warrant deeper investigation to understand the clinical implications fully.

Objective

This study aims to systematically evaluate the correlation between thyroid hormone levels, including thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4), and markers of renal disease severity. These markers include serum creatinine, urea, and parathyroid hormone (PTH) levels in individuals diagnosed with CK).

Methods

We conducted a cross-sectional observational study involving a cohort of 86 participants with CKD recruited from the renal clinic at King Fahad Hospital in Tabuk. Biochemical parameters, encompassing plasma electrolytes and thyroid hormone concentrations, were quantitatively assessed. These measurements were performed with the aid of a Roche Cobas E411 analyzer. The Pearson correlation coefficient was employed to delineate the strength and direction of the associations between the thyroid function markers and renal disease indicators.

Results

The statistical analysis highlighted a generally weak correlation between the concentrations of thyroid hormones and the indicators of renal disease severity, with Pearson correlation coefficients between -0.319 and 0.815. Critically, no significant correlation was found between creatinine and thyroid hormones (TSH, T3, T4), nor was any substantial correlation between urea and thyroid hormones. Conversely, a robust positive correlation was noted between the levels of parathyroid hormone and serum creatinine (r = 0.718, p < 0.001).

Conclusion

The data suggests that thyroid hormone levels have a minimal correlation with the severity of renal disease markers. In contrast, the pronounced correlation between PTH and creatinine underscores the importance of considering PTH as a significant factor in managing and therapeutic intervention of CKD complications. These initial findings catalyze further research to thoroughly investigate the pathophysiological relationships and potential therapeutic targets concerning thyroid dysfunction in patients with renal impairment.

Evaluation of thyroid profile among children aged 1-15 years with nephrotic syndrome: An observation study

BACKGROUND

The interaction between the kidney and the thyroid is important for normal function of both organs. In nephrotic syndrome, proteinuria leads to loss of several proteins, which in turn causes hypothyroidism.

AIM

To assess the thyroid function in children with nephrotic syndrome.

METHODS

This cross-sectional study was conducted in a tertiary center, Bhopal, from February 2020 to January 2021. Consecutive children aged 1-15 years admitted with nephrotic syndrome (first-time diagnosed and all relapse cases) were included in the study. A thyroid profile was sent along with routine investigations, and thyroid hormone status was assessed in nephrotic syndrome children.

RESULTS

Of the 70 patients, 39 (55.7%) showed abnormal thyroid profiles; 19 (27.1%) had overt hypothyroidism, and 20 (28.6%) had subclinical hypothyroidism. Overt hypothyroidism was seen in 16.1% of newly diagnosed cases, 40% of second relapses, and 2.7% of frequently relapsed cases (P < 0.001). The mean serum free T3 and free T4 levels in frequent relapses were 2.50 ± 0.39 ng/dL and 0.78 ± 0.12 ng/dL, respectively, which were significantly lower than in newly diagnosed cases (2.77 ± 0.37 ng/dL and 0.91 ± 0.19 ng/dL, respectively). The mean thyroid-stimulating hormone (TSH) level was significantly higher in frequent relapses 5.86 ± 1.56 µIU/mL) and second relapse (5.81 ± 1.78 µIU/mL) than in newly diagnosed cases (4.83 ± 0.76 µIU/mL) and first relapse cases (4.74 ± 1.17 µIU/mL), (P < 0.01).

CONCLUSION

An abnormal thyroid profile was commonly observed in children with nephrotic syndrome, and overt hypothyroidism was more common in frequent relapse cases. Therefore, thyroid screening should be a part of the management of nephrotic syndrome so that hypothyroidism can be detected and managed at an early stage.

Prognostic implications of thyroid hormones in acute aortic dissection: mediating roles of renal function and coagulation

Background

Thyroid hormones significantly influence cardiovascular pathophysiology, yet their prognostic role in acute aortic dissection (AAD) remains inadequately explored. This study assesses the prognostic value of thyroid hormone levels in AAD, focusing on the mediating roles of renal function and coagulation.

Methods

We included 964 AAD patients in this retrospective cohort study. Utilizing logistic regression, restricted cubic splines, and causal mediation analysis, we investigated the association between thyroid hormones and in-hospital mortality and major adverse cardiovascular events (MACEs).

Results

In AAD patients overall, an increase of one standard deviation in FT4 levels was associated with a 31.9% increased risk of MACEs (OR 1.319; 95% CI 1.098-1.584) and a 36.1% increase in in-hospital mortality (OR 1.361; 95% CI 1.095-1.690). Conversely, a higher FT3/FT4 ratio was correlated with a 20.2% reduction in risk of MACEs (OR 0.798; 95% CI 0.637-0.999). This correlation was statistically significant predominantly in Type A AAD, while it did not hold statistical significance in Type B AAD. Key renal and coagulation biomarkers, including blood urea nitrogen, creatinine, cystatin C, prothrombin time ratio, prothrombin time, and prothrombin time international normalized ratio, were identified as significant mediators in the interplay between thyroid hormones and MACEs. The FT3/FT4 ratio exerted its prognostic influence primarily through the mediation of renal functions and coagulation, while FT4 levels predominantly impacted outcomes via a partial mediation effect on coagulation.

Conclusion

FT4 levels and the FT3/FT4 ratio are crucial prognostic biomarkers in AAD patients. Renal function and coagulation mediate the association between the thyroid hormones and MACEs.

Relationship of Thyroid Function with Renal Hemodynamics and Cholesterol Metabolism in Proteinuric Kidney Disease: A Pilot Study

Nephrotic syndrome and hypothyroidism are respectively reported to influence renal hemodynamics and hypercholesterolemia. However, the relationship of proteinuria-associated thyroid function with renal hemodynamics and cholesterol metabolism has yet to be determined in a simultaneous analysis of thyroid, renal, and cholesterol variables. We investigated the hypothesis that the changes in thyroid hormones by proteinuria may contribute to changes in cholesterol metabolism and renal hemodynamics by proteinuria. Twenty-nine patients (17 men and 12 women) with proteinuric kidney disease (mean age 46 years) were enrolled in a pilot study. Data for serum free triiodothyronine (FT3), free thyroxine (FT4), total cholesterol, and filtration fraction (FF; assessed by para-aminohippuric acid clearance) were used in variable-adjusted correlation analyses. The patients had the following data (mean ± standard deviation): urinary protein 5.18 ± 3.28 g/day, FT3 2.18 ± 0.44 pg/mL, FT4 1.03 ± 0.26 ng/dL, FF 0.27 ± 0.07, and total cholesterol 327 ± 127 mg/dL. There was a significant positive correlation of FT3 with FF (β = 0.58, p = 0.01) and a significant inverse correlation of FT4 with total cholesterol (β = -0.40, p = 0.01). A positive correlation of FT3 with FF and an inverse correlation of FT4 with total cholesterol were demonstrated in patients with proteinuric kidney disease. The proteinuria-associated reduction in serum thyroid hormone levels was correlated with hypercholesterolemia and the reduced glomerular FF. Further studies of these relationships are required.

Impact of Thyroid Status on Incident Kidney Dysfunction and Chronic Kidney Disease Progression in a Nationally Representative Cohort

OBJECTIVE

To examine the relationship between thyroid status and incident kidney dysfunction/chronic kidney disease (CKD) progression.

PATIENTS AND METHODS

We examined incident thyroid status, ascertained by serum thyrotropin (TSH) levels measured from January 1, 2007, through December 31, 2018, among 4,152,830 patients from the Optum Labs Data Warehouse, containing deidentified retrospective administrative claims data from a large national health insurance plan and electronic health record data from a nationwide network of provider groups. Associations of thyroid status, categorized as hypothyroidism, euthyroidism, or hyperthyroidism (TSH levels >5.0, 0.5-5.0, and <0.5 mIU/L, respectively), with the composite end point of incident kidney dysfunction in patients without baseline kidney dysfunction and CKD progression in those with baseline CKD were examined using Cox models.

RESULTS

Patients with hypothyroidism and hyperthyroidism had higher risk of incident kidney dysfunction/CKD progression in expanded case-mix analyses (reference: euthyroidism): adjusted hazard ratios (aHRs) (95% CIs) were 1.37 (1.34 to 1.40) and 1.42 (1.39 to 1.45), respectively. Incrementally higher TSH levels in the upper reference range and TSH ranges for subclinical, mild overt, and overt hypothyroidism (≥3.0-5.0, >5.0-10.0, >10.0-20.0, and >20.0 mIU/L, respectively) were associated with increasingly higher risk of the composite end point (reference: TSH level, 0.5 to <3.0 mIU/L): aHRs (95% CIs) were 1.10 (1.09 to 1.11), 1.37 (1.34 to 1.40), 1.70 (1.59 to 1.83), and 1.70 (1.50 to 1.93), respectively. Incrementally lower TSH levels in the subclinical (<0.5 mIU/L) and overt (<0.1 mIU/L) hyperthyroid ranges were also associated with the composite end point: aHRs (95% CIs) were 1.44 (1.41 to 1.47) and 1.48 (1.39 to 1.59), respectively.

CONCLUSION

In a national cohort, TSH levels in the upper reference range or higher (≥3.0 mIU/L) and below the reference range (<0.5 mIU/L) were associated with incident kidney dysfunction/CKD progression.

Association study of urinary iodine concentrations and coronary artery disease among adults in the USA: National Health and Nutrition Examination Survey 2003-2018

Iodine is a vital trace element in the human body and is associated with several important coronary artery disease (CAD) risk factors. We aimed to explore the correlation between urinary iodine concentration (UIC) and CAD. Data from 15 793 US adults in the National Health and Nutrition Examination Survey (2003-2018) were analysed. We conducted multivariable logistic regression models and fitted smoothing curves to study the correlation between UIC and CAD. Furthermore, we performed subgroup analysis to investigate possible effect modifiers between them. We found a J-shaped association between UIC and CAD, with an inflection point at Lg UIC = 2·65 μg/l. This result indicated a neutral association (OR 0·89; 95 % CI 0·68, 1·16) between UIC and CAD as Lg UIC < 2·65 μg/l, but the per natural Lg [UIC] increment was OR 2·29; 95 % CI 1·53, 3·43 as Lg UIC ≥ 2·65 μg/l. An interaction between diabetes and UIC might exist. The increase in UIC results in an increase in CAD prevalence (OR 1·84, 95 % CI 1·32, 2·58) in diabetes but results in little to no difference in non-diabetes (OR 0·98, 95 % CI 0·77, 1·25). The J-shaped correlation between UIC and CAD and the interaction between diabetes and UIC should be confirmed in a prospective study with a series of UIC measurements. If excessive iodine precedes CAD, then this new finding could guide clinical practice and prevent iodine deficiency from being overcorrected.

The diurnal change of thyroid-stimulating hormone and the effect of this change on thyroid functions in patients with chronic kidney disease

PURPOSE

Thyroid-stimulating hormone (TSH) has a pulsatile and circadian rhythm in healthy individuals. We aimed to evaluate the diurnal changes of free thyroid hormones and serum TSH levels in patients with end-stage renal failure (ESRF) whose thyroidal functions are at normal ranges.

METHODS

Thirty hemodialysis patients with chronic renal failure and without a known thyroidal disease who are over 18 and 35 healthy individuals were included. The serum TSH, free T3, and free T4 levels were examined among the patient and control group which were taken at 8:00 a.m., 4:00 p.m., and 0:00 a.m.

RESULTS

Twenty-two (73.3%) patients were male, and the mean age of the patient group was 64 (sd = 14.45 years). Seventeen (48.6%) of the control group were female, and the mean age was 31.9 (sd = 6.4 years). Serum free T3 levels, measured at three different time points (8:00 a.m., 4:00 p.m., and 0:00 a.m.), were significantly lower in the patient group than in the control group and serum free T4 levels were measured at three different time points (8:00 am, 4:00 p.m., and 0:00 a.m.) were significantly higher in the patient group than in the control group. Serum TSH levels were higher in the patient group than in the control group at 08:00, and were lower at 24:00 (p < 0.001). The nocturnal increase of serum TSH level under 0.525 suggested diurnal rhythm disruption with 83% sensitivity and 87% specificity.

CONCLUSION

The nocturnal serum TSH increase is not seen in ESRF patients who did not have a thyroid disease. We think that not observing a nocturnal TSH increase could be an early indication of the sick euthyroid syndrome.

Development and Validation of a Prediction Model for Incident Hypothyroidism in a National Chronic Kidney Disease Cohort

CONTEXT

Hypothyroidism is a common yet under-recognized condition in patients with chronic kidney disease (CKD), which may lead to end-organ complications if left untreated.

OBJECTIVE

We developed a prediction tool to identify CKD patients at risk for incident hypothyroidism.

METHODS

Among 15 642 patients with stages 4 to 5 CKD without evidence of pre-existing thyroid disease, we developed and validated a risk prediction tool for the development of incident hypothyroidism (defined as thyrotropin [TSH] > 5.0 mIU/L) using the Optum Labs Data Warehouse, which contains de-identified administrative claims, including medical and pharmacy claims and enrollment records for commercial and Medicare Advantage enrollees as well as electronic health record data. Patients were divided into a two-thirds development set and a one-third validation set. Prediction models were developed using Cox models to estimate probability of incident hypothyroidism.

RESULTS

There were 1650 (11%) cases of incident hypothyroidism during a median follow-up of 3.4 years. Characteristics associated with hypothyroidism included older age, White race, higher body mass index, low serum albumin, higher baseline TSH, hypertension, congestive heart failure, exposure to iodinated contrast via angiogram or computed tomography scan, and amiodarone use. Model discrimination was good with similar C-statistics in the development and validation datasets: 0.77 (95% CI 0.75-0.78) and 0.76 (95% CI 0.74-0.78), respectively. Model goodness-of-fit tests showed adequate fit in the overall cohort (P = .47) as well as in a subcohort of patients with stage 5 CKD (P = .33).

CONCLUSION

In a national cohort of CKD patients, we developed a clinical prediction tool identifying those at risk for incident hypothyroidism to inform prioritized screening, monitoring, and treatment in this population.

Subclinical Hypothyroidism, Kidney, and Heart from Normal to Uremic Milieu

Thyroid hormone (TH) imbalances, particularly subclinical hypothyroidism (SCHT), are associated with chronic kidney disease (CKD) and end-stage kidney disease (ESKD). SCHT is more prevalent in CKD and ESKD patients than in the general population, and this condition increases the risk of cardiovascular disease (CVD) morbidity and mortality. The risk of CVD is higher in CKD and ESKD patients compared with the general population. Traditional and nontraditional risk factors, including TH abnormalities, contribute to the high CVD burden in CKD and ESKD patients. The review discusses the link between CKD and hypothyroidism, with a focus on SCHT, and the mechanisms that lead to CVD burden.

Spectrum of Thyroid Dysfunction in Patients with Chronic Kidney Disease in Benin City, Nigeria

There is an indication of abrupt rise in chronic kidney disease (CKD) in Nigeria and thyroid function involvement has not been sufficiently evaluated. This study determined thyroid gland function among subjects with CKD in Benin City, Nigeria. A total of 184 randomized CKD patients attending specialist clinic and 80 healthy control subjects were recruited for this study. A well-structured questionnaire was used to obtain data on socio-demography. Blood specimens were collected and used for the determination of thyroid function parameters; thyroid stimulating hormone (TSH), triiodothyronine (T3), free triiodothyronine (fT3), thyroxine (T4), free thyroxine (fT4), thyroid peroxidase antibody (TPO-Abs), thyroid globulin antibody (Tg-Abs) and Deiodinase enzyme Type 1 (D1). SPINA GD and SPINA GT were calculated using Michaelis-Menten model. The CKD was classified into stages using Modification of Drug in Renal Disease (MDRD) formula. Thyroid dysfunctions observed were clinical hyperthyroidism 1 (0.54%), non-thyroidal illness 78 (42.4%), clinical hypothyroidism 11 (6.0%), sub-clinical hyperthyroidism 3 (1.60%), and sub-clinical hypothyroidism 11 (6.0%), while euthyroid were 80 (43.5%). SPINA GD of CKD patients (33.85 ± 10.94) was not significantly different when compared with controls (24.85 ± 1.57), whereas, SPINA GT was significantly higher (p < 0.01) among CKD patients (3.74 ± 0.31) than controls (2.68 ± 0.11). Autoimmune thyroid disease demonstrated by positive Tg-Abs and TPO-Abs were observed among approximately 7.9% of CKD patients. Serum TPO-Abs concentration increased with CKD progression. Thyroid dysfunction is involved in the pathogenesis of CKD patients. The etiologies are multifactorial and immunological mechanisms of autoimmune thyroid disease may be a contributing factor.

Triiodothyronine and Protein Malnutrition Could Influence Pulse Wave Velocity in Pre-Dialysis Chronic Kidney Disease Patients

Cardiovascular diseases (CVD) are the first cause of chronic kidney disease (CKD) mortality. For personalized improved medicine, detecting correctable markers of CVD can be considered a priority. The aim of this study was the evaluation of the impact of nutritional, hormonal and inflammatory markers on brachial-ankle Pulse Wave Velocity (PWV) in pre-dialysis CKD patients. A cross-sectional observational study was conducted on 68 pre-dialysis CKD patients (median age of 69 years, 41.2% with diabetes mellitus, 52.9% male). Laboratory data were collected, including levels of prolactin, triiodothyronine, TGF α, IL-6, and IL-1β. The high values of brachial-ankle PWV were associated with reduced muscle mass (p = 0.001, r = -0.44), low levels of total cholesterol (p = 0.04, r = -0.26), triglycerides (p = 0.03, r = -0.31), triiodothyronine (p = 0.04, r = -0.24), and prolactin (p = 0.02, r = -0.27). High PWV was associated with advanced age (p < 0.001, r = 0.19). In the multivariate analysis, reduced muscle mass (p = 0.018), low levels of triiodothyronine (p = 0.002), and triglycerides (p = 0.049) were significant predictors of PWV, but age (p < 0.001) remained an important factor. In conclusion, reduced triiodothyronine together with markers of malnutrition and age were associated with PWV in pre-dialysis CKD patients.

Thyroid Dysfunction and Chronic Kidney Disease: A Study Among the Northeastern Population of India

INTRODUCTION

 Chronic kidney disease (CKD) is a multifaceted non-communicable disease characterized by a progressive decline in kidney function ultimately requiring renal replacement therapy (RRT) in most patients. Due to the high cost and availability of a limited number of donors, the majority of patients depend on dialysis and conservative management. Thyroid hormones are indispensable for the growth, development, and homeostasis of our body. The kidney plays an important role in the metabolism, degradation, and excretion of thyroid hormones. Various studies have revealed significant dysfunction in thyroid hormone status in CKD patients, but the results are inconsistent.

AIMS

To evaluate and compare the thyroid hormone status in CKD patients with healthy controls along with a comparison of thyroid hormones in CKD patients on regular hemodialysis with those on conservative management.

MATERIALS AND METHODS

 The present cross-sectional study involved 100 subjects of both sexes between 40 and 70 years of age, out of which 50 were patients of stage 5 CKD with no previous history of any thyroid disorders, while 50 apparently healthy subjects served as control. Of the CKD patients, 52% were on regular hemodialysis while 48% were receiving conservative care. The participants were investigated for various biochemical parameters like blood urea, serum creatinine, total triiodothyronine (TT3), total thyroxine (TT4), and thyroid stimulating hormone (TSH). The estimated glomerular filtration rate (eGFR) was calculated using a modification of diet in renal disease (MDRD) 4 variable formula. The thyroid profiles were also compared between patients of CKD receiving conservative management and those on maintenance hemodialysis.

RESULTS

 Of the total sample, 35 (70%) were male and 15 (30%) were female in each of the case and control groups. The mean age of CKD patients and the control group was 55.32 ± 9.62 years and 54.48 ± 9.63 years, respectively. TT3 was reduced in all 50 CKD patients. TT4 was normal in 31 (62%), reduced in 18 (36%), and high in one (2%) case. TSH was high in 38 (76%) cases, while reduced in one (2%) and normal in 11 (22%) cases. The mean blood level of TT3 and TT4 showed a statistically significant reduction (P < 0.0001 for each), while the TSH level showed a significant increase with a p-value of 0.0002 in CKD patients compared to controls. The mean blood urea and serum creatinine levels were statistically increased in cases than in controls (P < 0.0001). The thyroid hormone status revealed a significant difference between CKD patients on maintenance hemodialysis compared to those on conservative care with a p-value of 0.0005 for TT3, 0.0006 for TT4, and 0.0055 for TSH.

CONCLUSION

 Patients with CKD were at risk of thyroid hypofunction irrespective of their mode of treatment. This study highlights the clinically relevant interactions between renal and thyroid function, which may be helpful to clinicians for optimal diagnosis and management of CKD patients.

Prevalence and Determinants of Hypothyroidism in Patients on Routine Hemodialysis in Somalia: A Cross-Sectional Study

Introduction

In recent decades, the relationship between thyroid and kidney disease has drawn considerable attention. We aim to assess the prevalence and the determinants of hypothyroidism in hemodialysis patients in Somalia.

Materials and Methods

This is a cross-sectional study which was conducted in the hemodialysis unit of Mogadishu Somalia Turkish Training and Research Hospital, between June 1 and July, 31 2022. A total of 301 patients who are routinely going to hemodialysis were included in the study. Demographic data including age, gender, and data regarding hemodialysis were extracted from hospital information system (HIS). All participants had their thyroid function test measured before hemodialysis sessions.

Results

A total of 301 patients were examined. Their ages ranged from 40 to 66 years, with the median age being 54 (IQR= 40-66). Males were 167 (55.5%) compared to females 134 (44.5%). Hypertension was the most common comorbidity among the patients with 137 (45.5%). Diabetic kidney disease was the most common cause of renal failure in 138 patients (45.84%) followed by hypertensive kidney disease 100 (33.22%). The prevalence rate of hypothyroidism in hemodialysis patients in our study was 28%. In hypothyroidism patients 57.8% had subclinical hypothyroidism and 42.2% had overt hypothyroidism. 70.8% of our patients were in euthyroid status. Subclinical hypothyroidism was commonly seen in patients with diabetes, hypertension, and heart disease. We found that increasing age, decreased albumin level were related to higher risk of subclinical hypothyroidism. We also found that increasing creatinine levels were associated with lower risk of overt hypothyroidism.

Conclusion

The prevalence rate of hypothyroidism in hemodialysis patients was 28%, with 57.8% showing subclinical hypothyroidism and 42.2% overt hypothyroidism. Increased age and low albumin level was associated with the prevalence of subclinical hypothyroidism in hemodialysis patients. Also low creatinine level was observed in overt hypothyroidism patients.

Elevated serum thyrotropin levels and endothelial dysfunction in a prospective hemodialysis cohort

INTRODUCTION

Thyroid dysfunction is a highly prevalent yet under-recognized complication in hemodialysis patients. In the general population, hypothyroidism has been associated with endothelial dysfunction due to impaired vasodilator synthesis and activity. Little is known about the association of serum thyrotropin (TSH), the most sensitive and specific single biochemical metric of thyroid function, with endothelial function in hemodialysis patients.

METHODS

In a secondary analysis of 99 patients from the Anti-inflammatory and anti-oxidative nutrition in hypoalbuminemic dialysis patients (AIONID) trial, we examined measurements of serum TSH and endothelial function ascertained by fingertip digital thermal monitoring (DTM), a novel method used to measure micro-vascular reactivity, collected within a 90-day period. DTM was used to measure changes in fingertip temperature during and after an ischemic stimulus (blood pressure cuff occlusion) as an indicator of changes in blood flow, and two DTM indices were assessed, namely adjusted (a) Temperature Rebound (TR), defined as the maximum temperature rebound post-cuff deflation, and adjusted (b) Area Under the Temperature Curve (TMP-AUC), defined as area under the curve between the maximum and minimum temperatures. We examined the relationship between serum TSH with impaired TR (separately) and TMP-AUC (both defined as less than the median level of observed values) using multivariable logistic regression.

FINDINGS

In unadjusted and case-mix analyses, higher serum TSH levels (defined as the three highest quartiles) were associated with lower (worse) TR (ref: lowest TSH quartile): ORs (95% CI) 2.64 (1.01-6.88) and 2.85 (1.08-7.57), respectively. In unadjusted and case-mix analyses, higher TSH levels were associated with lower (worse) TMP-AUC: ORs (95% CI) 2.64 (1.01-6.88) and 2.79 (1.06-7.38), respectively.

DISCUSSION

In HD patients, higher serum TSH levels were associated with worse micro-vascular reactivity measured by DTM. Further studies are needed to determine if thyroid hormone supplementation improves endothelial function in hemodialysis patients with lower levels of thyroid function.

Association of Reduced Free T3 to Free T4 Ratio with Lower Serum Creatinine in Japanese Hemodialysis Patients

PURPOSE

Low T3 syndrome is defined by a fall in free triiodothyronine (FT3) in spite of normal serum thyroid-stimulating hormone (TSH) and often normal free thyroxin (FT4). A low FT3/FT4 ratio, a relevant marker for low T3 syndrome, is known as a risk of mortality in hemodialysis (HD) patients, as well as low muscle mass in the general population. Because of the local activation of T4 to FT3 in muscle tissue, we examined the association of FT3/FT4 ratio with serum creatinine, a marker of muscle mass and strength in HD patients to investigate the significance of muscle tissue in the development of low T3 syndrome in HD patients.

METHODS

This was a cross-sectional study derived from our prospective cohort study, named DREAM, of Japanese HD patients. After the exclusion of patients with treated and untreated thyroid dysfunction, 332 patients were analyzed in the study.

RESULTS

The serum FT4 and TSH of HD patients (n = 332) were 0.9 ± 0.1 ng/dL. and 2.0 ± 0.9 μIU/mL, which were within the respective normal range, while serum FT3 was 2.2 ± 0.3 pg/mL. As many as 101 out of 332 (30.4%) HD patients exhibited a serum FT3 less than the normal lower limit of 2.2 pg/mL. The serum FT3/FT4 ratio correlated significantly positively with serum creatinine, and inversely with serum log CRP and total cholesterol, while it exhibited a tendency towards positive correlation with serum albumin. Multiple regression analysis, which included serum creatinine, albumin, and log CRP, simultaneously, in addition to sex, age, diabetic kidney disease or not, log HD duration, body mass index, systolic blood pressure, and Kt/V, as independent variables, revealed an independent and significant positive association of serum creatinine, but not serum albumin or CRP, with the serum FT3/FT4 ratio.

CONCLUSIONS

The present study demonstrated an independent and positive correlation of serum creatinine with the serum FT3/FT4 ratio in HD patients. The lack of association of the serum FT3/FT4 ratio with serum albumin and CRP suggested the presence of a creatinine-specific mechanism to associate with serum FT3/FT4 ratio. Because of the local activation of T4 to T3 at muscle tissue, a lower muscle mass may be causatively associated with low T3 syndrome.

Impact of Hypothyroidism on Patients with Hepatocellular Carcinoma Undergoing Liver Transplantation

BACKGROUND

This work endeavored to explore the effect of hypothyroidism on mortality in subjects with HCC who underwent living-donor liver transplantation (LDLT).

METHODS

This prospective study included 107 patients with HCC subjected to LDLT, divided into hypothyroid group (n=53) and euthyroid group (n=54). The primary objectives were overall and disease-free survival (DFS).

RESULTS

Euthyroid and hypothyroid groups were comparable in all baseline characteristics except the age of patients. Overall survival (OS) of the whole group at 48 months was 68.8%, while the DFS was 60.2%. On univariate analysis, OS was negatively affected by the older age of the patients (p<0.001) or the donor (p<0.001), hypothyroidism (p=0.008), HBV (p=0.029), larger tumor size (p=0.023), and defective Milan criteria (p=0.022). On multivariate analysis, the age of the patients and donors was the independent factor affecting OS. On univariate analysis, DFS was negatively affected by older age of the patients (p < 0.001) or the donor (p=0.005), hypothyroidism (p=0.005), HBV (p=0.019), larger tumor size (p=0.023), and defective Milan criteria (p=0.020). On multivariate analysis, the age of the patients, thyroid status, and Milan criteria were the independent factors affecting DFS.

CONCLUSION

Hypothyroidism is a risk factor for worse outcomes in HCC patients after liver transplantation.

Renal Cortical Perfusion Estimated in Color Doppler Dynamic Tissue Perfusion Measurement in Patients Treated with Levothyroxine Following Total Thyroidectomy for Resectable Thyroid Cancer Is Independently Associated with Free Thyroxine: A Single-Center Prospective Study

Background

The thyroid state significantly influences renal function. However, a direct link between thyroid and kidney dysfunction has not been identified. Thyroid hormones affect cardiac output and vascular resistance, and thus can modify kidney perfusion. This prospective study aimed to test the association between renal cortical perfusion (RCP) estimated in color Doppler sonographic dynamic tissue perfusion measurement (DTPM) with thyroid hormones in 36 patients treated with levothyroxine following total thyroidectomy for resectable thyroid cancer.

Material/Methods

Blood tests, blood pressure monitoring, and DTPM of the renal cortex were performed. To exclude possible reading errors, the intrarater reliability of the ultrasound perfusion measurement method was estimated.

Results

The absolute difference between the 2 ultrasound RCP measurements was 5.2±4.4%. RCP correlated significantly with free thyroxine (FT₄) (r=0.46; p=0.006) but not with triiodothyronine and thyroid-stimulating hormone. In the adjusted to age backward stepwise multivariable regression analysis model, including estimated glomerular filtration rate, mean arterial pressure, and FT₄, only FT₄ was independently associated with RCP (R²=0.21; p=0.006).

Conclusions

Renal cortical perfusion is independently associated with free thyroxine, which can contribute to renal function abnormalities in the condition of impaired thyroid function. This small prospective study from a single center showed that the renal cortex’s color Doppler sonographic dynamic tissue perfusion measurement had very good intraobserver reproducibility.

Effects of 2-ethylhexyl-4-methoxycinnamate (EHMC) on thyroid hormones and genes associated with thyroid, neurotoxic, and nephrotoxic responses in adult and larval zebrafish (Danio rerio)

One of the most widely used UV filters, 2-ethylhexyl-4-methoxycinnamate (EHMC), has been widely detected in the environment. While its endocrine disruption potential has often been reported, toxicological information on EHMC is limited. This study was conducted to determine the thyroid, neurological and renal toxicity potentials of EHMC in adult male and embryo-larval zebrafish (Danio rerio). Following 21 d of exposure, plasma T3 concentration decreased in a concentration-dependent manner in adult zebrafish. Several genes related to thyroid hormone regulation were also downregulated in the brain, thyroid, and liver of the adult fish. In addition, upregulation of syn2a in the brain and downregulation of podocin and wt1a in the kidney were observed following the exposure in adult fish. In zebrafish larvae, following 120 h exposure to EHMC, whole-body T3 and T4 contents decreased, and thyroid hormone-related genes were downregulated. However, several genes showed different patterns of transcription in the larvae; for example, mbp and etv1 genes were downregulated and podocin was upregulated. Unlike adult fish, the larval fish showed significant genetic changes related to neurotoxicity. The hypothyroidism induced in the larval fish by the exposure might be potentially associated with the neurotoxic potential of EHMC. The implications of the observed hormonal and transcriptional-level changes in zebrafish at different life stages following long-term exposure warrant further investigation.

A Pilot Trial on the Effect of Levothyroxine on Proteinuria in Patients With Advanced CKD

INTRODUCTION

Thyroid hormones can directly affect kidney function; elevated levels of thyroid-stimulating hormone (TSH) and chronic kidney disease (CKD) are associated with proteinuria, decreased estimated glomerular filtration rate (eGFR), and progression to end-stage renal disease. Our hypothesis is that in patients with CKD and TSH at levels considered to be in the low subclinical hypothyroidism (SCH) range, lowering TSH with levothyroxine (LVX) improves the clinical parameters of renal function.

METHODS

This was a double-blind, randomized, pilot clinical trial in patients with proteinuric CKD (eGFR <60 ml/min per 1.73 m2 and proteinuria >150 mg/d) performed at the Hospital Civil de Guadalajara, with the intention of lowering TSH (levels of 1.25-2.5 μIU/l) in patients with TSH (levels of 2.6-9.9 μIU/ml with FT4 in the range of 0.7-1.8 ng/dl). Patients were randomized 1:1 to receive LVX or placebo for 12 weeks. The primary objective was to evaluate absolute levels of proteinuria at the beginning compared to the end of the study and, as a secondary objective, the changes in serum creatinine (sCr), eGFR, cholesterol, triglycerides, low-density lipoprotein (LDL), and blood pressure, and to assess the tolerability and safety of LVX.

RESULTS

Between March and November 2018, a total of 163 patients were assessed for eligibility; 119 patients did not meet the inclusion criteria or were excluded, and 32 patients were randomized. The demographic and clinical characteristics of the 2 study groups were essentially not different. Subjects were 66.87 (SD 12.19) years of age, 62.5% were female, 75% were diabetes mellitus, eGFR was 23.55 (±12.91) ml/min per 1.73 m2, TSH was 5.37 ± 2.13 μIU/ml, proteinuria in 24-hour urine collection was 1.52 ± 1.12, and all of them were taking angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs). Proteinuria at 12 weeks in the LVX group was 0.89 SD ± 1.28 g/d, and in the placebo group it was 1.35 SD ± 0.85 g/d; when compared to placebo, LVX showed a significant decrease in proteinuria of 1.1 g/d (P = 0.0011). The eGFR in the LVX group showed an improvement of 4 ml/min/1.73 m2 (P = 0.049); in the placebo group, there was a decrease of 1.98 ml/min per 1.73 m2. The sCr, cholesterol, triglycerides, low-density lipoprotein, systolic blood pressure, and diastolic blood pressure were not different between groups. Adverse events were reported in the LVX group in 7.14% of patients and in 11.11% of patients in the placebo group; none left the study because of adverse effects, and there were no serious adverse events.

CONCLUSION

This single-center, randomized, double-blind, placebo-controlled pilot clinical trial in patients with advanced proteinuric CKD who already used ACEIs or ARBs demonstrated that administering LVX to obtain a TSH range close to 2.5 μIU/ml decreased proteinuria and improved eGFR. Future research is needed to confirm our results and to determine whether our findings generalize to patient groups not explicitly enrolled in this small pilot trial.

Bidirectional Interaction of Thyroid-Kidney Organs in Disease States

Purpose

Thyroid hormones play an important role in growth, development, and physiology of the kidney. The kidney plays a key role in the metabolism, degradation, and excretion of thyroid hormones and its metabolites. The aim of this study is to investigate the prevalence of disease states of thyroid-kidney organs and detecting the correlation between thyroid and kidney function abnormalities.

Materials and Methods

In this retrospective study, a total of forty-five patients with thyroid and kidney dysfunction were investigated. Clinical features, laboratory data at initial presentation, management, and outcomes were collected. The paper has been written based on searching PubMed and Google Scholar to identify potentially relevant articles or abstracts. Median, percentage, mean ± standard deviation (SD), and the two-tailed t-test were used for statistical analyses. The correlation between variables was assessed by Pearson's, Spearman's correlation tests and regression analyses.

Results

The mean ± SD of age of study patients was 48.2 ± 22.93 years (ranging from 1 to 90 years). There was no correlation between serum thyroid-stimulating hormone, free thyroxine levels with estimated glomerular filtration rate, and proteinuria. No association between antimicrosomal antibodies with estimated glomerular filtration rate was seen. Cardiovascular disease was the most common complication of overt hypothyroidism in kidney dysfunction patients.

Conclusion

The present study showed more prevalence of primary hypothyroidism in comparison with other thyroid dysfunctions in patients with kidney dysfunction. Reduced mean values of thyroid function profiles after treatment suggest that this thyroid disease should be considered and ameliorated with thyroid hormone replacement therapy in patients with kidney disease.

THE ASSOCIATION OF SUBCLINICAL INSULIN RESISTANCE WITH THYROID AUTOIMMUNITY IN EUTHYROID INDIVIDUALS

Hashimoto thyroiditis is characterized by anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-Tg) antibodies that gradually lead to thyroid cell destruction. As hypothyroidism has been associated with insulin resistance (IR), we aimed to investigate whether IR is associated with thyroid antibody presence and whether the degree of IR correlates with their concentration in euthyroid individuals. A total of 164 non-diabetic, euthyroid individuals, average age 34 years, were included in the study, divided into two groups according to Hashimoto thyroiditis and underwent 5-hour oral glucose tolerance test. The degree of IR was evaluated by the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). The Hashimoto thyroiditis group had higher HOMA-IR (p=0.003) and lower glucose levels (p=0.04). HOMA-IR correlated positively with anti-TPO (p<0.001). Linear logistic regression revealed that anti-TPO concentration increased by 18.13 (p=0.001) with each HOMA-IR unit. IR might trigger thyroid antibody production and Hashimoto thyroiditis development, which needs to be evaluated in further larger scale follow up studies.

Thyroid dysfunction and cardiovascular events in patients with chronic kidney disease: A protocol of systematic review and meta-analysis

BACKGROUND

Cardiovascular disease is the main cause of death in patients with chronic kidney disease (CKD). Studies have found that hypothyroidism can significantly increase cardiovascular risk. Meanwhile, hypothyroidism is a common complication of CKD, but the correlation between hypothyroidism and cardiovascular risk in CKD patients has not been verified and paid enough attention. We therefore plan to conduct a systematic review and meta-analysis to explore whether hypothyroidism was independently predictive for the cardiovascular risk in patients with CKD.

METHODS

We will search in PubMed, Embase Database, Web of Science, China National Knowledge Infrastructure (CNKI), China Biology Medicine Database (CBM), and Wanfang Database, and include the cross-sectional studies, case--control studies, and cohort studies that explore the association between hypothyroidism and cardiovascular risk in CKD patients. According to the eligibility criteria, two researchers will independently screen the retrieved literature, evaluate the methodological quality, and extract data. We will combine the extracted data based on STATA and TSA software.

RESULTS

This systematic review will assess the association between hypothyroidism and cardiovascular risk in CKD patients based on the incidence of cardiovascular events in CKD people with hypothyroidism.

CONCLUSIONS

This study will provide more evidence for the correlation between hypothyroidism and cardiovascular risk in CKD patients, which will contribute to the management and clinical practice of CKD population.

ETHICS AND DISSEMINATION

This protocol is based on available literatures so that the ethical approval and informed consent are not applicable. The results of this study will be published in a peer-reviewed journals or relevant conferences.

PROTOCOL REGISTRATION NUMBER

INPLASY2020100022.

Outcomes of Cardiac Resynchronization Therapy in Patients with Hypothyroidism and Heart Failure

Background

Hypothyroidism is known to be associated with adverse clinical outcomes in heart failure. The association between hypothyroidism and cardiac resynchronization therapy outcomes in patients with severe heart failure is not clear.

Methods

The study included 1316 patients who received cardiac resynchronization therapy between 2002 and 2015. Baseline demographics and cardiac resynchronization therapy outcomes, including left ventricular ejection fraction, New York Heart Association class, appropriate implantable cardioverter-defibrillator therapy, and all-cause mortality, were collected from the electronic health record.

Results

Of the study cohort, 350 patients (26.6%) were classified as the hypothyroidism group. The median duration of follow-up was 3.6 years (interquartile range, 1.7–6.2 years). Hypothyroidism was not associated with a higher risk of all-cause mortality in patients receiving CRT for heart failure. The risk of appropriate implantable cardioverter-defibrillator therapy significantly increased in association with increased baseline thyroid-stimulating hormone level in the entire cohort (hazard ratio, 1.23 per 5mIU/L increase; 95% CI, 1.01–1.5; P = 0.04) as well as in the hypothyroid group (hazard ratio, 1.44 per 5mIU/L increase; 95% CI, 1.13–1.84; P = 0.004).

Conclusions

CRT improves cardiac function in hypothyroid patients. The ventricular arrhythmic events requiring ICD therapies are associated with baseline TSH level, which might be considered as an important biomarker to stratify the risk of sudden death for patients with heart failure and hypothyroidism.

Prevalence of Hypothyroidism among Dialysis Patients in Palestine: A Cross-Sectional Study

Introduction

The kidney affects the thyroid gland causing various derangements in its function whenever the kidney is impaired, even with a minor imperfection in its job, and this makes dialysis patients more prone to thyroid disorders with subsequent increase in mortality and morbidity. This study aims to assess the prevalence of thyroid disease (hypo- and hyperthyroidism) among dialysis patients and their associated factors.

Methods

This cross-sectional study was conducted in the dialysis unit of An-Najah National University Hospital. 209 dialysis patients (60% were male, 57.6 ± 14.5 years, mean age) meeting our inclusion criteria were tested for thyrotropin (TSH) and free thyroxine (FT4) in addition to routine laboratory tests. Findings. The prevalence of hypothyroidism was assessed as 16.3% (95% CI = 11.29% to 21.3%), overt hypothyroidism was 9.1%, and subclinical hypothyroidism was 7.2%. Subclinical hyperthyroidism prevalence was 1%, and no overt hyperthyroidism cases were reported. We observed no significant association between thyroid state and age, gender, duration of dialysis, or weight. Discussion. Hypothyroidism (both subclinical and overt type) is commonly seen in dialysis patients, and its symptoms are ordinary complains even in euthyroid dialysis patients, and this warrants screening programs and more studies on the efficacy of thyroid hormone supplements.

Association of thyroid status prior to transition to end-stage renal disease with early dialysis mortality

BACKGROUND

Advanced chronic kidney disease (CKD) patients, including those receiving dialysis, have a high prevalence of thyroid dysfunction. Although hypothyroidism is associated with higher death risk in end-stage renal disease (ESRD) patients, no studies have examined whether thyroid status in the pre-ESRD period impacts mortality after dialysis initiation.

METHODS

Among US veterans with CKD identified from the national Veterans Affairs database that transitioned to dialysis over the period from October 2007 to September 2011, we examined the association of pre-ESRD serum thyrotropin (TSH) levels averaged over the 1-year pre-dialysis ('prelude') period with all-cause mortality in the first year following dialysis initiation.

RESULTS

Among 15 335 patients in the 1-year prelude cohort, TSH levels >5.0 mIU/L were associated with higher mortality in expanded case-mix Cox models (reference: TSH 0.5-5.0 mIU/L): adjusted hazard ratio (aHR) [95% confidence interval (CI) 1.20 (1.07-1.33). Similar findings were observed for TSH >5.0 mIU/L and mortality in the 2- and 5-year cohorts: aHRs (95% CI) 1.11 (1.02-1.21) and 1.15 (1.07-1.24), respectively. Analyses of finer gradations of TSH in the 1-year prelude cohort demonstrated that incrementally higher levels >5.0 mIU/L were associated with increasingly higher mortality in expanded case-mix models (reference: TSH 0.5-3.0 mIU/L): aHRs (95% CI) 1.18 (1.04-1.33) and 1.28 (1.03-1.59) for TSH levels >5.0-10.0 mIU/L and >10.0 mIU/L, respectively. In the 2- and 5-year cohorts, mortality associations persisted most strongly for those with TSH >10.0 mIU/L, particularly after laboratory covariate adjustment.

CONCLUSIONS

Among new ESRD patients, there is a dose-dependent relationship between higher pre-ESRD TSH levels >5.0 mIU/L and post-ESRD mortality. Further studies are needed to determine the impact of TSH reduction with thyroid hormone supplementation in this population.

Association between hypothyroidism and chronic kidney disease observed among an adult population 55 years and older

Hypothyroidism and chronic kidney disease (CKD) are highly prevalent conditions with a potential mechanistic link. We sought to determine whether hypothyroidism is associated with CKD among a large diverse community-based cohort.A cross-sectional study was performed (January 1, 1990-December 31, 2017) within a large integrated health system. Individuals age ≥55 years of age with outpatient measurements of thyroid stimulating hormone (TSH) and ≥2 serum creatinine values were included. Hypothyroidism was defined as TSH >4 mIU/L and/or receipt of thyroid hormone replacement and further categorized as hypothyroid status: TSH >4 mcIU/mL and attenuated-hypothyroid status: TSH <4 mcIU/mL with receipt of thyroid hormone replacement. Euthyroidism was defined as TSH <4 mIU/L and no thyroid hormone replacement. Our primary measure was CKD defined as an estimated glomerular filtration rate (eGFR) <45 mL/min/1.73 m. Multivariable logistic regression adjusting for age, sex, race, and comorbidities was used to estimate odds ratios (OR) for CKD by thyroid status.Among 378,101 individuals, 114,872 (30.4%) had hypothyroidism among whom 31,242 and 83,630 had hypothyroid and attenuated-hypothyroid statuses, respectively. Individuals with hypothyroidism had a CKD OR (95%CI) of 1.25 (1.21-1.29) compared with those with euthyroidism. Granular examination of thyroid statuses showed that hypothyroid and attenuated-hypothyroid statuses had CKD ORs (95% CI) of 1.59 (1.52-1.66) and 1.12 (1.08-1.16), respectively. A similar relationship was observed in analyses that defined CKD as an eGFR <60 L/min/1.73 m.Among individuals 55 years and older, we observed that those with hypothyroidism were more likely to have CKD. A stronger association was found among patients of hypothyroid status compared with attenuated-hypothyroid status suggesting a dose dependent relationship.

Association of Subclinical Thyroid Dysfunction with Chronic Kidney Disease: A Systematic Review and Meta-analysis

Background: The association of subclinical thyroid dysfunction (SCTD) with chronic kidney disease (CKD) among community population remains inconclusive. Our aim was to evaluate the association between SCTD and the risk of CKD by conducting a meta-analysis.Methods: Multiple databases were searched to identify studies on the association between SCTD and risk of CKD, up to October 2018. Relevant information for analysis was extracted. A random-effects model was used to calculate the pooled risk estimate.Results: Eight articles were included in this meta-analysis, with three cohort and five cross-sectional studies. The pooled odds ratio (OR) of subclinical hypothyroidism for CKD was 1.37 (95% CI: 1.13-1.67, P = .000, n = 8) in a multivariable-adjusted model. A significant association was observed in subgroup younger than 70 years (OR = 1.40, 95% CI: 1.09-1.79, P = .000, n = 6), but not in subgroup older than 70 years (OR = 1.28, 95% CI: 0.89-1.83, P = .186, n = 2). For subclinical hyperthyroidism, the summary OR was 1.16 (95%CI: 0.97-1.39, P = .115, n = 5) and subgroup analyses by age and study design did not alter the results significantly.Conclusions: Our findings demonstrated that subclinical hypothyroidism was significantly associated with a higher risk of CKD independent of some conventional risk factors among community population and age might have modifying effects on the association.

The kidney, subclinical thyroid disease and cardiovascular outcomes in older patients

OBJECTIVE

Thyroid hormones have been implicated to play a role in cardiovascular disease, along with studies linking thyroid hormone to kidney function. The aim of this study is to investigate whether kidney function modifies the association of subclinical thyroid dysfunction and the risk of cardiovascular outcomes.

METHODS

In total, 5804 patients were included in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER). For the current analysis, 426 were excluded because of overt thyroid disease at baseline or 6 months, 266 because of inconsistent thyroid function at baseline and 6 months, 294 because of medication use that could influence thyroid function, and 16 because of missing kidney or thyroid values. Participants with normal fT4 were classified, based on TSH both at inclusion and 6 months, into three groups: subclinical hypothyroidism (TSH >4.5 mIU/L); euthyroidism (TSH = 0.45-4.5 mIU/L); and subclinical hyperthyroidism (TSH <0.45 mIU/L). Strata of kidney function were made based on estimated glomerular filtration rate into three clinically relevant groups: <45, 45-60, and >60 mL/min/1.73 m2. The primary endpoint consists of death from coronary heart disease, non-fatal myocardial infarction and (non)fatal stroke.

RESULTS

Mean age was 75.3 years, and 49.0% patients were male. Mean follow-up was 3.2 years. Of all participants, 109 subjects (2.2%) had subclinical hypothyroidism, 4573 (94.0%) had euthyroidism, and 182 (3.7%) subclinical hyperthyroidism. For patients with subclinical hypothyroidism, euthyroidism, and subclinical hyperthyroidism, primary outcome occurred in 9 (8.3%), 712 (15.6%), and 23 (12.6%) patients, respectively. No statistically significant relationship was found between subclinical thyroid dysfunction and primary endpoint with adjusted hazard ratios of 0.51 (0.24-1.07) comparing subclinical hyperthyroidism and 0.90 (0.58-1.39) comparing subclinical hypothyroidism with euthyroidism. Neither was this relationship present in any of the strata of kidney function, nor did kidney function interact with subclinical thyroid dysfunction in the association with primary endpoint (P interaction = 0.602 for subclinical hyperthyroidism and 0.388 for subclinical hypothyroidism).

CONCLUSIONS

In this secondary analysis from PROSPER, we found no evidence that the potential association between thyroid hormones and cardiovascular disease is modified by kidney function in older patients with subclinical thyroid dysfunction.

Thyroid disease in end-stage renal disease

PURPOSE OF REVIEW

Hypothyroidism is a highly prevalent endocrine disorder in the end-stage renal disease (ESRD) population, yet many cases may remain latent and undiagnosed.

RECENT FINDINGS

Epidemiologic data show that there is a nearly five-fold higher prevalence of hypothyroidism in advanced chronic kidney disease (CKD) patients vs. those without CKD. Given that the metabolism, degradation, and excretion of thyroid hormone and its metabolites, as well as the regulation of the hypothalamic-pituitary-thyroid axis may be altered in ESRD, certain considerations should be made when interpreting thyroid functional tests in these patients. Growing evidence shows that hypothyroidism and other thyroid functional test derangements are associated with higher risk of cardiovascular disease, worse patient-centered outcomes, and survival in the advanced CKD population, including those with ESRD. Although limited data examining treatment of hypothyroidism suggests benefit, further studies of the efficacy and safety of thyroid hormone supplementation, including clinical trials and rigorous longitudinal observational studies are needed to inform the management of thyroid dysfunction in CKD.

SUMMARY

Given the high burden of hypothyroidism in ESRD patients, and potential ill effects on their cardiovascular health, patient-centered outcomes, and survival, further research is needed to inform the optimal management of thyroid dysfunction in this population.

A prognostic role for non-thyroidal illness syndrome in chronic renal failure:a systematic review and meta-analysis

BACKGROUND

Chronic renal failure (CRF) is a serious disease that has become a burden on global and local economics and public health. In addition, non-thyroidal illness syndrome (NTIS) has become increasingly more prevalent in CRF patients.

MATERIALS AND METHODS

A data search was conducted on the PubMed/Medline, Cochrane Library, Web of Science, Embase, and CBM databases to identify studies up to November 1st, 2018, that compared low T3 and normal T3 levels in patients with CRF. Data analysis was done by calculating the relative risks (RR) and 95% confidence intervals (95% CI) and continuous variables were described by weighted mean difference (WMD) and 95% CI. The efficacy outcomes included renal function and mortality. The Newcastle-Ottawa Scale and Agency for Healthcare Research and Quality scale were used to assess the quality of the cohort and cross-sectional studies, respectively. A funnel plot was used to identify publication bias.

RESULTS

Seventeen studies with a total of 4593 patients were finally included in the analysis. Among the 17 studies, 11 reported the mortality of CRF patients with low T3 and normal T3 levels. Subgroups were assigned according to different follow-up times and different methods of treatment. The mortality rate in the low T3 group was much higher than in the normal T3 group. 11 studies reported creatinine (Cr) results in patients with low T3 and normal T3 levels and our analysis found no significant differences between the two groups (95%CI: 0.46-0.25; P-heterogeneity = 0.000; P = 0.559). Five studies reported uric acid results and we found no significant differences between the two groups (95%CI: 0.08-0.22; P-heterogeneity = 0.438; P = 0.377). Five studies reported the urea levels in the two groups and our analysis found no significant differences (95%CI: 1.60-1.23; I² = 0.0%; P-heterogeneity = 0.498;P = 0.798).

CONCLUSION

Low T3 had a greater impact on the short-term prognosis of patients with CRF than on the long-term prognosis. NTIS did not cause substantial kidney damage.

Metabolic signature associated with parameters of the complete blood count in apparently healthy individuals

Metabolomics studies now approach large sample sizes and the health characterization of the study population often include complete blood count (CBC) results. Upon careful interpretation the CBC aids diagnosis and provides insight into the health status of the patient within a clinical setting. Uncovering metabolic signatures associated with parameters of the CBC in apparently healthy individuals may facilitate interpretation of metabolomics studies in general and related to diseases. For this purpose 879 subjects from the population‐based Study of Health in Pomerania (SHIP)‐TREND were included. Using metabolomics data resulting from mass‐spectrometry based measurements in plasma samples associations of specific CBC parameters with metabolites were determined by linear regression models. In total, 118 metabolites significantly associated with at least one of the CBC parameters. Strongest associations were observed with metabolites of heme degradation and energy production/consumption. Inverse association seen with mean corpuscular volume and mean corpuscular haemoglobin comprised metabolites potentially related to kidney function. The presently identified metabolic signatures are likely derived from the general function and formation/elimination of blood cells. The wealth of associated metabolites strongly argues to consider CBC in the interpretation of metabolomics studies, in particular if mutual effects on those parameters by the disease of interest are known.

Successful treatment of myxedema coma with a combination of levothyroxine and liothyronine

Myxedema coma is a rare endocrine emergency resulting from the decompensation of severe hypothyroidism, which is associated with a high mortality rate. It is characterized by the deterioration of mental status, hypothermia, hypotension, hyponatremia, and hypoventilation. Early disease diagnosis and advancements in intensive supportive care have reduced the mortality rate. Besides intensive supportive care, appropriate management of the underlying thyroid hormone deficiency is essential. However, as the disease is rare and unrecognized, evidence-based treatment of myxedema has not yet been established in many countries. An 84-year-old Japanese man with a history of Hashimoto's thyroiditis was referred to our hospital. On arrival, conscious disturbance, hypothermia, hypotension, and hypoventilation were observed. He had discontinued thyroid hormone replacement therapy for a year. He was diagnosed with myxedema coma. Immediately, he received intensive supportive care and a combination therapy of 200 μg levothyroxine and 50 μg liothyronine until the fifth hospital day. Subsequently, monotherapy with levothyroxine was continued at a dose of 150 μg daily. The thyroid hormone level reached the normal range a few days later, and cardiovascular disease did not develop during hospitalization. This case demonstrated the efficacy of the combination of levothyroxine and liothyronine in treating myxedema coma.

Functional Abnormalities and Thyroid Nodules in Patients with End-stage Renal Disease

BACKGROUND/AIM

Clinical and subclinical hypothyroidism is more common in patients with end-stage renal disease (ESRD) than in the general population. Patients with ESRD with hypothyroidism are more susceptible to cardiovascular disease, with an increased risk of mortality than those with normal thyroid function. Moreover, these patients have higher incidence of benign and malignant nodules.

PATIENTS AND METHODS

This was a retrospective study on 2,147 patients with ESRD on the renal transplant waiting list between 2000 and 2015 aimed at identifying the presence of hypothyroidism and associated variables.

RESULTS

Hypothyroidism was detected in 437/2,147 (20.3%) patients, 289 of them having the subclinical form. Cardiovascular disease and older age were significantly associated with hypothyroidism, and autosomal polycystic kidney disease was correlated to goiter (p<0.001).

CONCLUSION

Thyroid abnormalities, particularly hypothyroidism with nodules, should be investigated in patients with ESRD on a waiting list for renal transplant to control cardiovascular complications and cancer risk.

Triiodothyronine attenuates the progression of renal injury in a rat model of chronic kidney disease

This study was designed to investigate whether and how triiodothyronine (T3) affects renal function in an experimental model of chronic kidney disease. Twenty-four female rats were divided into the following groups: sham-operated control group (n = 8), 5/6 nephrectomized group (Nx, n = 8), and 5/6 nephrectomized group treated with T3 for 2 weeks (T3-Nx, n = 8). T3 administration significantly decreased serum levels of urea, creatinine, tumour necrosis factorα, and interleukin-6 compared with serum levels in the Nx group. The levels of malondialdehyde, transforming growth factor β, fibronectin, and collagen IV, as well as the expression of inducible nitric oxide synthase, nuclear factor κB, poly(ADP-ribose) polymerase, caspase-3, and Bax were all significantly decreased, though not normalized, in the remnant kidney of rats in the T3-Nx group compared with Nx rats. Glutathione, heme oxygenase-1 levels, as well as endothelial nitric oxide synthase expression were increased in the remnant kidney of the T3-Nx group. Histological studies revealed focal necrosis of renal tubules associated with inflammatory cell infiltration and fibrosis in the Nx group. These changes were alleviated in T3-Nx rats. This study showed that T3 administration attenuated the clinical and histological signs of renal injury in 5/6 nephrectomized rats by mitigating renal oxidative stress, inflammation, apoptosis, and fibrosis.

Thyroid Status and Death Risk in US Veterans With Chronic Kidney Disease

OBJECTIVE

Given that patients with non-dialysis-dependent chronic kidney disease (NDD-CKD) have a disproportionately higher prevalence of hypothyroidism compared with their non-CKD counterparts, we sought to determine the association between thyroid status, defined by serum thyrotropin (TSH) levels, and mortality among a national cohort of patients with NDD-CKD.

PATIENTS AND METHODS

Among 227,422 US veterans with stage 3 NDD-CKD with 1 or more TSH measurements during the period October 1, 2004, to September 30, 2012, we first examined the association of thyroid status, defined by TSH categories of less than 0.5, 0.5 to 5.0 (euthyroidism), and more than 5.0 mIU/L, with all-cause mortality. We then evaluated 6 granular TSH categories: less than 0.1, 0.1 to less than 0.5, 0.5 to less than 3.0, 3.0 to 5.0, more than 5.0 to 10.0, and more than 10.0 mIU/L. We concurrently examined thyroid status, thyroid-modulating therapy, and mortality in sensitivity analyses.

RESULTS

In expanded case-mix adjusted Cox analyses, compared with euthyroidism, baseline and time-dependent TSH levels of more than 5.0 mIU/L were associated with higher mortality (adjusted hazard ratios [aHRs] [95% CI], 1.19 [1.15-1.24] and 1.23 [1.19-1.28], respectively), as were baseline and time-dependent TSH levels of less than 0.5 mIU/L (aHRs [95% CI], 1.18 [1.15-1.22] and 1.41 [1.37-1.45], respectively). Granular examination of thyroid status showed that incrementally higher TSH levels of 3.0 mIU/L or more were associated with increasingly higher mortality in baseline and time-dependent analyses, and TSH categories of less than 0.5 mIU/L were associated with higher mortality (reference, 0.5-<3.0 mIU/L) in baseline analyses. In time-dependent analyses, untreated and undertreated hypothyroidism and untreated hyperthyroidism were associated with higher mortality (reference, spontaneous euthyroidism), whereas hypothyroidism treated-to-target showed lower mortality.

CONCLUSION

Among US veterans with NDD-CKD, high-normal TSH (≥3.0 mIU/L) and lower TSH (<0.5 mIU/L) levels were associated with higher death risk. Interventional studies identifying the target TSH range associated with the greatest survival in patients with NDD-CKD are warranted.

Chronic kidney disease

Chronic kidney disease (CKD) is defined by persistent urine abnormalities, structural abnormalities or impaired excretory renal function suggestive of a loss of functional nephrons. The majority of patients with CKD are at risk of accelerated cardiovascular disease and death. For those who progress to end-stage renal disease, the limited accessibility to renal replacement therapy is a problem in many parts of the world. Risk factors for the development and progression of CKD include low nephron number at birth, nephron loss due to increasing age and acute or chronic kidney injuries caused by toxic exposures or diseases (for example, obesity and type 2 diabetes mellitus). The management of patients with CKD is focused on early detection or prevention, treatment of the underlying cause (if possible) to curb progression and attention to secondary processes that contribute to ongoing nephron loss. Blood pressure control, inhibition of the renin-angiotensin system and disease-specific interventions are the cornerstones of therapy. CKD complications such as anaemia, metabolic acidosis and secondary hyperparathyroidism affect cardiovascular health and quality of life, and require diagnosis and treatment.

Thyroid function, reduced kidney function and incident chronic kidney disease in a community-based population: the Atherosclerosis Risk in Communities study

BACKGROUND

Reduced kidney function is a common public health problem that increases risk for a wide variety of adverse outcomes, making the identification of potentially modifiable factors associated with the development of incident chronic kidney disease (CKD) important. Alterations in the hypothalamic-pituitary-thyroid axis have been linked to reduced kidney function, but the association of thyroid function with the development of incident CKD is largely uncharacterized.

METHODS

Concentrations of thyroid stimulating hormone (TSH), free thyroxine (FT4), triiodothyronine (T3) and thyroid peroxidase antibody (TPOAb) were quantified in 12 785 black and white participants of the ongoing community-based prospective Atherosclerosis Risk in Communities study. Thyroid markers and clinical categories of thyroid dysfunction (euthyroidism, combined subclinical and overt hypothyroidism, combined subclinical and overt hyperthyroidism) were also evaluated for their association with reduced kidney function (estimated glomerular filtration rate <60 mL/min/1.73 m2) at study baseline and with incident CKD over a median follow-up time of 19.6 years.

RESULTS

Higher TSH and FT4 as well as lower T3 concentrations were strongly and independently associated with reduced kidney function at study baseline. The clinical entities hypothyroidism and hyperthyroidism were also associated with higher odds of baseline reduced kidney function, but this was not significant. However, none of the markers of thyroid function nor different clinical categories of thyroid dysfunction (hypothyroidism, hyperthyroidism or TPOAb positivity) were associated with incident CKD in adjusted analyses.

CONCLUSIONS

Elevated TSH, FT4 and reduced T3 concentrations were associated with reduced kidney function cross-sectionally. The lack of association with the development of incident CKD suggests that altered thyroid function in the general population is not causally related to CKD development, but screening for thyroidal status may be especially relevant in persons with reduced kidney function.

Severe Thyrotoxicosis Secondary to Povidone-Iodine from Peritoneal Dialysis

A 73-year-old male on home peritoneal dialysis (PD) with recent diagnosis of atrial fibrillation presented with fatigue and dyspnea. Hyperthyroidism was diagnosed with TSH < 0.01 mIU/L and FT4 > 100 pmol/L. He had no personal or family history of thyroid disease. There had been no exposures to CT contrast, amiodarone, or iodine. Technetium thyroid scan showed diffusely decreased uptake. He was discharged with a presumptive diagnosis of thyroiditis. Three weeks later, he had deteriorated clinically. Possible iodine sources were again reviewed, and it was determined that povidone-iodine solution was used with each PD cycle. Methimazole 25 mg daily was initiated; however, he had difficulty tolerating the medication and continued to clinically deteriorate. He was readmitted to hospital where methimazole was restarted at 20 mg bid with high dose prednisone 25 mg and daily plasma exchange (PLEX) therapy. Biochemical improvement was observed with FT4 dropping to 48.5 pmol/L by day 10, but FT4 rebounded to 67.8 pmol/L after PLEX was discontinued. PLEX was restarted and thyroidectomy was performed. Pathology revealed nodular hyperplasia with no evidence of thyroiditis. Preoperative plasma iodine levels were greater than 5 times the upper limit of normal range. We hypothesize that the patient had underlying autonomous thyroid hormone production exacerbated by exogenous iodine exposure from a previously unreported PD-related source.

Thyroid Status, Quality of Life, and Mental Health in Patients on Hemodialysis

BACKGROUND AND OBJECTIVES

In the general population, there is increasing recognition of the effect of thyroid function on patient-centered outcomes, including health-related quality of life and depression. Although hypothyroidism is highly prevalent in hemodialysis patients, it is unknown whether thyroid status is a risk factor for impaired health-related quality of life or mental health in this population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined the association of thyroid status, defined by serum thyrotropin, with health-related quality of life and depressive symptoms over time in a prospective cohort of 450 patients on hemodialysis from 17 outpatient dialysis facilities from May of 2013 to May of 2015 who underwent protocolized thyrotropin testing, Short-Form 36 surveys, and Beck Depression Inventory-II questionnaires every 6 months. We examined the association of baseline and time-dependent thyrotropin categorized as tertiles and continuous variables with eight Short-Form 36 domains and Beck Depression Inventory-II scores using expanded case mix plus laboratory adjusted linear mixed effects models.

RESULTS

In categorical analyses, the highest baseline thyrotropin tertile was associated with a five-point lower Short-Form 36 domain score for energy/fatigue (P=0.04); the highest time-dependent tertile was associated with a five-point lower physical function score (P=0.03; reference: lowest tertile). In continuous analyses, higher baseline serum thyrotropin levels (+Δ1 mIU/L) were associated with lower role limitations due to physical health (β=-1.3; P=0.04), energy/fatigue (β=-0.8; P=0.03), and pain scores (β=-1.4; P=0.002), equivalent to five-, three-, and five-point lower scores, respectively, for every 1-SD higher thyrotropin. Higher time-dependent thyrotropin levels were associated with lower role limitations due to physical health scores (β=-1.0; P=0.03), equivalent to a three-point decline for every 1-SD higher thyrotropin. Baseline and time-dependent thyrotropin were not associated with Beck Depression Inventory-II scores.

CONCLUSIONS

In patients on hemodialysis, higher serum thyrotropin levels are associated with impaired health-related quality of life across energy/fatigue, physical function, and pain domains. Studies are needed to determine if thyroid-modulating therapy improves the health-related quality of life of hemodialysis patients with thyroid dysfunction.

Thyroid Status and Mortality in a Prospective Hemodialysis Cohort

CONTEXT AND OBJECTIVE

Compared with the general population, hemodialysis patients have a substantially higher risk of hypothyroidism, as defined by an elevated serum thyrotropin (TSH) level, and cardiovascular mortality. Whereas an elevated TSH is associated with cardiovascular disease and death in the general population, associations among dialysis patients have been inconsistent.

DESIGN, SETTING, PARTICIPANTS, AND MAIN OUTCOME

We examined 541 hemodialysis patients from 17 southern California dialysis centers in the prospective Hypothyroidism, Cardiovascular Health, and Survival study who underwent protocolized measurement of repeated serum TSH levels every 6 months from 2013 to 2015. Associations between TSH tertiles (<1.28, 1.28 to <2.14, and 2.14 to 86.7 mIU/L) and mortality were estimated using time-dependent Cox models with four adjustment levels. In sensitivity analyses, we excluded patients receiving thyroid hormone supplementation.

RESULTS

Compared with the lowest TSH tertile, the highest TSH tertile was associated with a 2.2- to 2.5-fold higher mortality risk in unadjusted, case-mix, expanded case-mix+laboratory, and expanded case-mix+laboratory+medication models [hazard ratios (95% confidence interval), 2.54 (1.32 to 4.89), 2.53 (1.30 to 4.93), 2.19 (1.11 to 4.32), and 2.28 (1.45 to 3.58), respectively]. We observed a consistent trend between higher TSH tertiles and numerically higher mortality risk across all models. Similar findings were observed in analyses excluding patients receiving thyroid hormone supplementation.

CONCLUSION

In time-dependent analyses, TSH levels in the high-normal to high range were independently associated with higher death risk in hemodialysis patients. Further studies are indicated to determine whether normalization of TSH levels with thyroid hormone supplementation improves survival in this population.

Subclinical hypothyroidism and the risk of chronic kidney disease in T2D subjects: A case-control and dose-response analysis

Evidence indicated a positive association between subclinical hypothyroidism (SCH) and cardiovascular diseases. But the relationship between SCH and chronic kidney diseases (CKD) remains unclear. A case-control study was performed to ascertain this relationship followed by a meta-analysis. In this hospital-based, case-control study, we recruited 3270 type 2 diabetic patients with euthyroidism and 545 type 2 diabetic patients with SCH. All English studies were searched upon the relationship between SCH and CKD up to October 2016. Meta-analysis was performed using STATA 13.0 software. Our case-control study indicated an association between SCH and CKD in patients with type 2 diabetes [OR (95% CI): 1.22 (1.09-1.36)]. Five observational studies reporting risk of CKD in SCH individuals were enrolled. A significant relationship between SCH and CKD was shown [pooled OR 1.80, (95% CI) 1.38-2.35]. Among normal TSH range, individuals with TSH ≥3.0 μIU/ml had a significantly higher rate of CKD (Fisher exact test, P = 0.027). Dose-response linear increase of CKD events was explored [pooled OR 1.09 (95% CI): 1.03-1.16 per1 mIU/L increase of TSH]. The present evidence suggests that SCH is probably a significant risk factor of CKD in T2D. Linear trend is shown between TSH elevation and CKD in T2D. This relationship between serum TSH and renal impairment in type 2 diabetic patients needs further studies to investigate.

Diagnosis of myxedema coma complicated by renal failure: a case report

Myxedema coma, caused by severe lack of thyroid hormone, is characterized by deterioration of mental status, hypothermia, hypotension, hyponatremia, and hypoventilation. We describe an 84-year-old woman who presented with renal failure and new onset severe hypothyroidism leading to challenges in the recognition of myxedema coma.

Thyroid function in end stage renal disease and effects of frequent hemodialysis

INTRODUCTION

End-stage renal disease (ESRD) is associated with perturbations in thyroid hormone concentrations and an increased prevalence of hypothyroidism. Few studies have examined the effects of hemodialysis dose or frequency on endogenous thyroid function.

METHODS

Within the Frequent Hemodialysis Network (FHN) trials, we examined the prevalence of hypothyroidism in patients with ESRD. Among those with endogenous thyroid function (without overt hyper/hypothyroidism or thyroid hormone supplementation), we examined the association of thyroid hormone concentration with multiple parameters of self-reported health status, and physical and cognitive performance, and the effects of hemodialysis frequency on serum thyroid stimulating hormone (TSH), free thyroxine (FT4), and free tri-iodothyronine (FT3) levels. Conventional thrice-weekly hemodialysis was compared to in-center (6 d/wk) hemodialysis (Daily Trial) and Nocturnal (6 nights/wk) home hemodialysis (Nocturnal Trial) over 12 months.

FINDINGS

Among 226 FHN Trial participants, the prevalence of hypothyroidism was 11% based on thyroid hormone treatment and/or serum TSH ≥8 mIU/mL. Among the remaining 195 participants (147 Daily, 48 Nocturnal) with endogenous thyroid function, TSH concentrations were modestly (directly) correlated with age (r = 0.16, P = 0.03) but not dialysis vintage. Circulating thyroid hormone levels were not associated with parameters of health status or physical and cognitive performance. Furthermore, frequent in-center and nocturnal hemodialysis did not significantly change (baseline to month 12) TSH, FT4, or FT3 concentrations in patients with endogenous thyroid function.

DISCUSSION

Among patients receiving hemodialysis without overt hyper/hypothyroidism or thyroid hormone treatment, thyroid indices were not associated with multiple measures of health status and were not significantly altered with increased dialysis frequency.

Thyroid dysfunction and kidney disease: An update

Thyroid hormones influence renal development, kidney hemodynamics, glomerular filtration rate and sodium and water homeostasis. Hypothyroidism and hyperthyroidism affect renal function by direct renal effects as well as systemic hemodynamic, metabolic and cardiovascular effects. Hypothyroidism has been associated with increased serum creatinine and decreased glomerular filtration rate. The reverse effects have been reported in thyrotoxicosis. Most of renal manifestations of thyroid dysfunction are reversible with treatment. Kidney disease may also cause thyroid dysfunction by several mechanisms. Nephrotic syndrome has been associated to changes in serum thyroid hormone concentrations. Different forms of glomerulonephritis and tubulointerstitial disease may be linked to thyroid derangements. A high prevalence of thyroid hormone alteration has been reported in acute kidney injury. Thyroid dysfunction is highly prevalent in chronic kidney disease patients. Subclinical hypothyroidism and low triiodothyronine syndrome are common features in patients with chronic kidney disease. Patients treated by both hemodialysis and peritoneal dialysis, and renal transplantation recipients, exhibit thyroid hormone alterations and thyroid disease with higher frequency than that found in the general population. Drugs used in the therapy of thyroid disease may lead to renal complications and, similarly, drugs used in kidney disorders may be associated to thyroid alterations. Lastly, low thyroid hormones, especially low triiodothyronine levels, in patients with chronic kidney disease have been related to a higher risk of cardiovascular disease and all-cause mortality. Interpretation of the interactions between thyroid and renal function is a challenge for clinicians involved in the treatment of patients with thyroid and kidney disease.

Association of TSH Elevation with All-Cause Mortality in Elderly Patients with Chronic Kidney Disease

Chronic kidney disease (CKD) is a widespread condition in the global population and is more common in the elderly. Thyroid-stimulating hormone (TSH) level increases with aging, and hypothyroidism is highly prevalent in CKD patients. However, the relationship between low thyroid function and mortality in CKD patients is unclear. Therefore, we conducted a retrospective cohort study to examine the relationship between TSH elevation and all-cause mortality in elderly patients with CKD. This retrospective cohort study included individuals ≥65 years old with CKD (n = 23,786) in Taipei City. Health examination data from 2005 to 2010 were provided by the Taipei Databank for Public Health Analysis. Subjects were categorized according to thyroid-stimulating hormone (TSH) level as follows: low normal (0.34<TSH<1.074 mIU/L), middle normal (1.074≤TSH≤2.46 mIU/L), high normal (2.46<TSH<5.2 mIU/L), elevated I (5.2≤TSH<10 mIU/L), and elevated II (TSH≥10 mIU/L). Risk of mortality was evaluated using a Cox proportional hazard regression model adjusted for sex, age, hypertension, diabetes mellitus, CKD stage, serum albumin, high-density lipoprotein cholesterol, uric acid, hemoglobin, body mass index, glutamic-pyruvic transaminase, smoking, alcohol consumption, and history of cardiovascular disease (coronary artery disease, congestive heart failure, cerebral vascular disease), history of cancer, and history of chronic obstructive pulmonary disease. Our results showed that compared to the reference group (middle normal TSH), the risk of all-cause mortality was increased in the elevated I group (hazard ratio [HR], 1.21; 95% confidence interval [CI], 1.02–1.45) and elevated II group (HR, 1.30; 95% CI, 1.00–1.69). We found a significant association between TSH elevation and all-cause mortality in this cohort of elderly persons with CKD. However, determining the benefit of treatment for moderately elevated TSH level (5.2–10 mIU/L) in elderly patients with CKD will require a well-designed randomized controlled trial.

The association of thyroid function and the risk of kidney function decline: a population-based cohort study

OBJECTIVES

Thyroid dysfunction has been associated with kidney function decline, but mainly in cross-sectional studies. Therefore, we aimed to determine the association between thyroid and kidney function in a prospective population-based cohort study longitudinally.

DESIGN

Prospective cohort study.

METHODS

Participants aged ≥45 years from the Rotterdam Study with thyroid and kidney function assessment were included. Kidney function and new onset chronic kidney disease (CKD) were defined using estimated glomerular filtration ate (eGFR), with CKD defined as eGFR <60 mL/min/1.73 m² according to the CKD-EPI formula.

RESULTS

We included 5103 participants (mean age of 63.6 years) with a mean follow-up of 8.1 years. Cross-sectionally, higher TSH levels were associated with lower eGFR (Beta (β): -1.75 mL/min; 95% confidence interval (CI): -2.17, -1.33), in multivariable models adjusting for several cardiovascular risk factors including smoking, hypertension and history of coronary heart disease among others. In contrast, longitudinally, higher TSH levels were associated with less annual eGFR decline (β: -0.06 mL/min; CI: -0.11, -0.01) and lower CKD incidence (odds ratio 0.85, CI; 0.75, 0.96). Compared with euthyroid participants, subclinical hyperthyroid individuals had an increased risk for CKD whereas hypothyroid individuals had a decreased risk (P for trend = 0.04).

CONCLUSIONS

Hyperactive thyroid function is associated with increased risk of kidney function decline while hypothyroidism is associated with a decreased CKD risk. More insight is needed in the pathophysiological pathways connecting high thyroid function and kidney function decline.

DIAGNOSIS OF ENDOCRINE DISEASE: How reliable are free thyroid and total T3 hormone assays?

Hypothyroidism is a very common disorder worldwide, for which the usual treatment is monotherapy with levothyroxine (L-T₄). However, a number of patients treated with L-T₄ continue to report symptoms of hypothyroidism despite seemingly normal levels of thyroid-stimulating hormone (TSH), free-T₃ (FT₃) and free-T₄ (FT₄) measured by immunoassay. This review summarizes the limitations of the immunoassays commonly used to measure thyroid hormone levels and emphasizes the advantages of the role of liquid chromatography-tandem mass spectrometry (LC-MS/MS). Immunoassays for free thyroid hormone are affected by alterations in serum binding proteins that occur in many physiological and disease states. Multiple studies show falsely normal values for T₃, FT₃ and FT₄ by immunoassay that are below the reference interval when measured by (ultrafiltration) LC-MS/MS, a reference method. We suggest evaluation of thyroid hormone levels by ultrafiltration LC-MS/MS for patients who continue to experience hypothyroid symptoms on LT-4. This may help identify the approximately 20% subset of patients who would benefit from addition of T₃ to their treatment regimen (combination therapy).