High levels of thyroid-stimulating hormone (TSH) were associated with significantly higher mortality in patients with pulmonary arterial hypertension (PAH), according to a study published in BMJ Open Respiratory Research.

The association was present both with and without accounting for differences in age, sex, PAH etiology, and N-terminal-pro hormone brain natriuretic peptide (NT-proBNP) levels. Low levels of TSH were not associated with mortality, however.

TSH levels were also not found to be associated with other markers of PAH disease severity including right ventricular (RV) basal diameter, tricuspid annular plane systolic excursion (TAPSE), 6-minute walk distance (6MWD), or New York Heart Association (NYHA) Functional Class.


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“Despite several reports detailing connections between thyroid disease and the initial diagnosis of pulmonary hypertension, associations between thyroid dysfunction and the clinical course in patients with PAH are less well studied,” the authors said.

Read more about PAH prognosis

A total of 112 PAH patients were included in the study. These patients were predominantly White (89%) and female (83%) with a median age of 52 years. The patients were recruited between 2014 and 2016 and followed for 3 years.

Only 1 study prior to this one showed an association between TSH and PAH mortality. The current study repeats and validates the previous study’s results but also investigated the link between TSH and other metrics of PAH severity.

The lack of a link between TSH and the other metrics may indicate that the increased risk is independent of progressive right heart failure.

“In this line of thinking, elevated TSH could be a marker or mediator of systemic stress or a systemic vulnerability that is not specific to the cardiopulmonary axis,” the authors hypothesized. “Less than half of patients with PAH die from progressive right heart failure and TSH may reflect systemic vulnerabilities or a composite marker of systemic stress that is not otherwise well captured by cardiac-specific metrics, such as that seen with sick euthyroid syndrome.”

Reference

Pi H, Rayner SG, Ralph DD, et al. Thyroid-stimulating hormone and mortality in pulmonary arterial hypertension. BMJ Open Respiratory Research 2022;9:e001348. doi: 10.1136/bmjresp-2022-001348