The effect of thyroid function on clinical outcome in patients with heart failure

Abstract

Aims Thyroid dysfunction is known to effect cardiac function and is a risk factor for developing heart failure (HF). Data regarding the clinical significance of thyroid‐stimulating hormone (TSH) levels alone as a predictor of outcome in patients with HF is sparse. We evaluated the significance of TSH on clinical outcome in a large cohort of patients with chronic HF. Methods and results Patients with a diagnosis of HF at a Health Maintenance Organization (n = 5599) were followed for cardiac‐related hospitalizations and death. Median TSH levels were 2.2 mIU/L (interquartile range 1.4–3.5). We divided patients into quartiles based on TSH levels. Median follow‐up time was 434 days and the overall mortality rate was 13.2%. Both a high and a low TSH level was associated with an increased mortality rate. Cox regression analysis after adjustment for other significant predictors demonstrated that the highest TSH quartile was associated with increased mortality compared with those with the lowest mortality [second quartile: TSH 1.4–2.2 mIU/L, hazard ratio (HR) 1.36, 95% confidence interval (CI) 1.08–1.71, P = 0.01]. TSH was also an independent predictor of death and cardiac‐related hospitalization. Analysis of patients not on levothyroxine treatment (78%) demonstrated that TSH was an even stronger predictor of mortality (HR 1.54, 95% CI 1.17–2.03, P = 0.002). Additional analysis based on accepted clinical cut‐offs of TSH demonstrated that increasing TSH levels above normal were independently associated with increased mortality and cardiac‐related hospitalizations. Conclusions Increased TSH levels are associated with worse clinical outcome in patients with HF. Thyroid imbalance confers significant risk in HF and warrants attention.

Thyroid Hormone Replacement Therapy Attenuates Atrial Remodeling and Reduces Atrial Fibrillation Inducibility in a Rat Myocardial Infarction–Heart Failure Model

“…11, 12 Thus, cardiac tissue hypothyroidism coexists in HF and may contribute to HF development. Consistent with this theory, recent clinical data 24, 25 found that increased TSH levels (a clinical marker of hypothyroidism) are associated with worse clinical outcome in patients with HF.…”

Thyroid function on admission and outcome in patients hospitalized for acute decompensated heart failure

“…As such, reduced fT3 levels may have adverse effects on the cardiovascular system, and thus cause poor prognosis in patients with cardiovascular disease [13,14,16]. Numerous studies have also examined the relationship between TSH levels and outcomes in patients with chronic congestive heart failure [18,20,23]. However, the prognostic value of TSH remains controversial.…”

Thyroid Function Within the Normal Range and Risk of Coronary Heart Disease

“…Our results do not inform whether thyrotropin levels measured after the clinical onset of cardiovascular disease may have prognostic value, as suggested by some evidence. 60 In addition, we did not examine whether levels of thyroid function tests within the reference ranges may be differentially associated with all-cause mortality 16,61,62 or the risk of non-CHD outcomes, such as atrial fibrillation, 62,63 heart failure, 62 fractures, 64 dementia, 62,65 chronic kidney disease 66 or cancer mortality, 61 as suggested in some prospective studies. However, except for a modestly increased risk of chronic kidney disease, 66 these studies did not show increased disease risk among people with thyrotropin levels in the upper part of the reference range and thus do not provide evidence in support of lowering the upper thyrotropin reference limit.…”