Can resistance to thyroid hormone be linked to heart problems even in younger people?

Details

People with resistance to thyroid hormone due to a defective thyroid receptor β (RTHβ) experience adverse cardiovascular outcomes and premature mortality. It is unknown whether this reflects increased overall cardiovascular disease (CVD) risk or effects of elevated thyroxine on heart rhythm and contractility.

The researchers assessed CVD risk and measured plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP), a marker of reduced cardiac function, in 99 people with RTHβ. Their mean age was 41 years, and 37% were male. This was an observational assessment using QRISK3, plasma NT-proBNP measurement, matched healthy-control comparisons, and multiple linear regression; the abstract does not specify a more detailed study design.

For 82 participants, the mean QRISK3 score was 2.0% (SD range, as reported: 0.5–8.8%), compared with 1.3% (0.3–5.0%) in healthy controls matched for age, sex, and ethnicity (P = .005).

The RTHβ participants’ QRISK3 heart age was 49.8 ± 14.5 years, compared with their actual age of 44.5 ± 12.4 years. The difference was 5.3 years (95% confidence interval: 4.0–6.5 years; P < .001).

Among 79 RTHβ participants, mean plasma NT-proBNP was 51 pg/mL (SD range, as reported: 18–142 pg/mL). Of these values, 10.1% exceeded the age-specific 97.5th percentile of a large control sample.

In multiple linear regression, age and female sex were significant independent predictors of NT-proBNP (P ≤ .001), but free T3, free T4, TSH, and QRISK3 10-year CVD risk were not.

The authors conclude that elevated NT-proBNP, seen even in young people with RTHβ, suggests that myocardial dysfunction contributes to early adverse cardiovascular outcomes in this disorder. Increased atherosclerotic disease risk is likely to manifest later in life.

They recommend considering NT-proBNP measurement and cardiovascular risk assessment at first presentation and periodically during RTHβ follow-up.