This 5-year observational study shows that thyroid hormone supplementation increases major adverse cardiovascular events (MACE), cardiovascular death, and all-cause mortality in patients with heart failure. Indirectly, this is in accordance with the well-documented benefits of beta-adrenergic receptor blockade in persons with cardiac failure.
Clinically, in patients with concomitants hypothyroidism and heart failure, thyroid hormone supplementation should be started at a low dose, increased slowly, and aiming a higher TSH target than in general population.
Increased risk of MI (IRR 1.32, p<0.05) was observed for ongoing treatment, reduced risk (IRR 0.87, p<0.05) was observed for incident treatment.
Conclusion
On-going and incident LT4 treatment in patients with HF was associated with an increased risk of all-cause mortality, cardiovascular death, and MACE. Increased risk of MI was observed for on-going treatment, reduced risk was observed for incident treatment.
Hypothyroidism has detrimental effects on the cardiovascular system, but controversy remains concerning the benefits of levothyroxine (LT4) substitution in patients with heart failure (HF).
Examining the effects of LT4 in patients with HF.
Retrospective cohort study.
Setting
All Danish citizens aged ≥ 18 years diagnosed with HF between 1997-2012. LT4 treatment was identified from nationwide registers. Incidence rate ratios (IRR) were calculated using Poisson-regression models.
Outcomes
All-cause mortality, myocardial infarction (MI), cardiovascular death and major adverse cardiovascular events (MACE).
Results
224,670 patients were diagnosed with HF (mean age 70.7 years, 53% male).
6,560 patients were treated with LT4 at baseline
9,007 patients initiated LT4 during follow-up.
209,103 patients did not receive LT4.
During a median follow-up of 4.8 years, 147,253 patients died.
Increased risk of the following was observed for treatment on-going at baseline and initiated during follow-up, respectively:
All-cause mortality (IRR 1.25, IRR 1.13 p<0.05)
Cardiovascular death (IRR 1.23, IRR 1.11, p<0.05)
MACE (IRR 1.26, IRR 1.05, p<0.05)
Increased risk of MI (IRR 1.32, p<0.05) was observed for ongoing treatment, reduced risk (IRR 0.87, p<0.05) was observed for incident treatment.
Conclusion
On-going and incident LT4 treatment in patients with HF was associated with an increased risk of all-cause mortality, cardiovascular death, and MACE. Increased risk of MI was observed for on-going treatment, reduced risk was observed for incident treatment.
