This article is more than 5 years old. Information may no longer be current.

Hypothyroidism linked to poor prognosis in heart failure

Subclinical hypothyroidism in patients with preexisting heart failure was significantly associated with atrial fibrillation and ventricular assist device placement, cardiac transplantation or all-cause mortality, according to data published in Circulation: Heart Failure.

“Despite recommendations by the American Heart Association to evaluate thyroid function in all patients presenting with heart failure, there have not been any studies to comprehensively examine the role of thyroid hormone abnormalities in exacerbating heart failure in the outpatient setting,” Lakshmi Kannan, MD, MSc, from the division of endocrinology, diabetes and metabolism at Perelman School of Medicine at the University of Pennsylvania, and colleagues wrote.

Kannan and colleagues analyzed data from a large, prospective cohort study (Penn Heart Failure Study) to determine the association between thyroid dysfunction and cardiovascular outcomes in outpatients with preexisting heart failure (n = 1,365; mean age, 57 years; 35% women).

Cardiovascular outcomes assessed included New York Heart Association class of heart failure, atrial fibrillation and a composite end point of ventricular assist device placement, heart transplantation or all-cause mortality. Median follow-up was 4.2 years.

Most participants had either New York Heart Association class II (45%) or III (32%) symptoms of heart failure.

The researchers found that patients with more severe heart failure were more likely to have higher levels of thyroid-stimulating hormone and free thyroxine, but lower levels of total triiodothyronine. Atrial fibrillation was linked to higher concentrations of free thyroxine. There were 462 occurrences of the composite end point.

Adjusted analysis indicated that patients with subclinical hypothyroidism, defined as thyroid-stimulating hormone concentrations between 4.51 and 19.99 mIU/L with normal concentrations of free thyroxine, had a higher risk for the composite end point overall (HR = 1.82; 95% CI, 1.27-2.61), compared with those with euthyroidism. Patients with thyroid-stimulating hormone concentrations of 7 mIU/L or more also had an increased risk for the composite end point (HR = 3.25; 95% CI, 1.96-5.39), but those with thyroid-stimulating hormone levels between 4.51 and 6.99 mIU/L did not (HR = 1.26; 95% CI, 0.78-2.06).

Additionally, patients with isolated low triiodothyronine were more likely to die or receive ventricular assist device placement or a heart transplantation (HR = 2.12; 95% CI, 1.65-2.72).

“Our data indicate that thyroid function is a key prognostic indicator in patients with preexisting heart failure,” Kannan and colleagues concluded.

“Our findings indicate the need for future studies to explore therapeutic effects of thyroxine and triiodothyronine administration in heart failure,” they added. – by Alaina Tedesco

Disclosures: The authors report no relevant financial disclosures.