Association of Subclinical Hypothyroidism and Cardiovascular Disease With Mortality

Brian Desmarais — Sun, 09 Feb 2020 19:30:41 +0000

Date Added:

February 9, 2020

Journal/Publication:

Journal of the American Medical Association Network

Publication Date:

February 2, 2020

URL:

Association of Subclinical Hypothyroidism and Cardiovascular Disease With Mortality

Type:

Clinical Research Results

Format:

Article

DOI (1):

10.1001/jamanetworkopen.2019.20745

Keywords

subclinical hypothyroidism

MeSH

hypothyroidism

hyperthyroidism

Hormone Replacement Therapy

ablation techniques

And the controversies regarding subclinical hypothyroidism continue. James W. Mold, MD, MP

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Importance Subclinical hypothyroidism is a common clinical entity among US adults associated in some studies with an increase in the risk of cardiovascular disease (CVD) and mortality. However, the extent to which CVD mediates the association between elevated serum thyrotropin (TSH) and mortality has not yet been well established or sufficiently quantified.

Objective To elucidate the extent to which subclinical hypothyroidism, elevated serum TSH and normal serum free thyroxine, or high-normal TSH concentrations (ie, upper normative–range TSH concentrations) are associated with mortality through CVD among US adults.

Design, Setting, and Participants This cohort study relied on representative samples of US adults enrolled in the National Health and Nutrition Examination Survey in 2001 to 2002, 2007 to 2008, 2009 to 2010, and 2011 to 2012 and their mortality data through 2015. Data were analyzed from January to August 2019.

Main Outcomes and Measures Cox proportional hazards regression models were used to investigate associations between the TSH concentration category (subclinical hypothyroidism or tertiles of serum TSH concentrations within the reference range; low-normal TSH, 0.34-1.19 mIU/L; middle-normal TSH, 1.20-1.95 mIU/L; and high-normal TSH, 1.96-5.60 mIU/L) and all-cause mortality. Mediation analysis was used within the counterfactual framework to estimate natural direct associations (not through CVD) and indirect associations (through CVD).

Results Of 9020 participants, 4658 (51.6%) were men; the mean (SD) age was 49.4 (17.8) years. Throughout follow-up (median [interquartile range], 7.3 [5.4-8.3] years), serum thyroid function test results consistent with subclinical hypothyroidism and high-normal TSH concentrations were both associated with increased all-cause mortality (subclinical hypothyroidism: hazard ratio, 1.90; 95% CI, 1.14-3.19; high-normal TSH: hazard ratio, 1.36; 95% CI, 1.07-1.73) compared with the middle-normal TSH group. Cardiovascular disease mediated 14.3% and 5.9% of the associations of subclinical hypothyroidism and high-normal TSH with all-cause mortality, respectively, with the CVD mediation being most pronounced in women (7.5%-13.7% of the association) and participants aged 60 years and older (6.0%-14.8% of the association).

Conclusions and Relevance In this study, CVD mediated the associations of subclinical hypothyroidism and high-normal TSH concentrations with all-cause mortality in the US general population. Further studies are needed to examine the clinical benefit of thyroid hormone replacement therapy targeted to a middle-normal TSH concentration or active CVD screening for people with elevated TSH concentrations.

Author/s:

Inoue, K., Ritz, B., Brent, G.A.

Subclinical thyroid dysfunction is associated with adverse prognosis in heart failure patients with reduced ejection fraction

Jeffrey Wilson — Wed, 01 May 2019 20:12:59 +0000

Date Added:

May 1, 2019

Journal/Publication:

BMC Cardiovascular Disorders

Publisher:

BioMed Central

Publication Date:

April 4, 2019

Issue:

Volume:

URL:

Subclinical thyroid dysfunction is associated with adverse prognosis in heart failure patients with reduced ejection fraction

Type:

Meta-analyses, Reviews, and Guidelines

Format:

Article

DOI (1):

10.1186/s12872-019-1055-x

Keywords

hypothyroidism

hyperthyroidism

subclinical hypothryroidism

subclinical hyperthyroidism

PMID (1):

30947691

MeSH

hyperthyroidism

hypothyroidism

thyroid diseases

The adverse impacts of “subclinical” hypo- and hyperthyroidism have been extensively studied. Few have been found. Subclinical hyperthyroidism is associated with incident atrial fibrillation. This meta-analysis concluded that both subclinical hypo- and hyperthyroidism are associated with increased all-cause mortality rates in patients with congestive heart failure. James W. Mold, MD, MPH

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BACKGROUND:

Subclinical thyroid dysfunction whose typical patterns include subclinical hypothyroidism and subclinical hyperthyroidism, has been indicated to be associated with an increased risk of heart failure (HF). However, the relationship between subclinical thyroid dysfunction and the clinical outcomes of HF patients is uncertain. This meta-analysis was conducted to assess the association between subclinical thyroid dysfunction and the clinical outcomes of HF patients.

METHODS:

Pubmed, Embase, Web of Science and Cochrane Central Register of Clinical Trials were searched for eligible studies published up to August 1, 2018 which reported the association between subclinical thyroid dysfunction and the clinical outcomes of HF patients. The pooled hazard ratio (HR) with the corresponding 95% confidence interval (CI) was used to assess the association.

RESULTS:

Fourteen studies met the eligibility criteria and a total of 21,221 patients with heart failure were included in the meta-analysis. Compared with HF patients with euthyroidism, the pooled HR of subclinical hypothyroidism for all-cause mortality was 1.45 (95% CI 1.26-1.67) in a randomized effects model with mild heterogeneity (I2 = 40.1, P = 0.073). The pooled HR of subclinical hypothyroidism for cardiac death and/or hospitalization was 1.33 (1.17-1.50) in a randomized effects model with moderate heterogeneity (I2 = 69.4, P < 0.001). Subclinical hyperthyroid can increase the risk of all-cause mortality without heterogeneity (HR 1.31, 95% CI 1.10-1.55, I2 = 25.5%, P = 0.225) but have no influence on the risk of cardiac death and/or hospitalization (HR 1.03, 95% CI 0.87-1.23, I2 = 0.0%, P = 0.958). These significant adverse associations were also retained in subgroup analysis. Sensitivity analysis demonstrated the stability of the results of our meta-analysis.

CONCLUSIONS:

Both subclinical hypothyroidism and subclinical hyperthyroidism are associated with adverse prognosis in patients with HF. Subclinical thyroid dysfunction may be a useful and promising predictor for the long-term prognosis in HF patients.

Author/s:

Yang, Guodong, Wang, Ya, Ma, Aiqun, Wang, Tingzhong