Objective Graves’ disease (GD) can both aggravate pre-existing cardiac disease and cause de novo heart failure (HF), but large-scale studies are lacking. We aimed to investigate the incidence, risk factors and outcomes of incident GD-related HF.

Methods Patients with GD (2009–2019) were retrospectively included. HF with reduced ejection fraction (HFrEF) was defined by left ventricular ejection fraction <50% and Framingham criteria, while HF with preserved ejection fraction (HFpEF) was defined according to the HFA-PEFF criteria. HF due to ischaemia, valve disorder or other structural heart disease was excluded. Proportional hazards regression was used to analyse risk factors and outcomes.

Results Of 1371 patients with GD, HF occurred in 74 (5.4%) patients (31 (2.3%) HFrEF; 43 (3.1%) HFpEF). In HFrEF, atrial fibrillation (AF) (HR 10.5 (3.0–37.3), p<0.001) and thyrotropin receptor antibody (TRAb) level (HR 1.05 (1.01–1.09) per unit, p=0.007) were independent risk factors. In HFpEF, the independent risk factors were chronic obstructive pulmonary disease (HR 7.2 (3.5–14.6), p<0.001), older age (HR 1.5 (1.2–2.0) per 10 years, p=0.001), overt hyperthyroidism (HR 6.4 (1.5–27.1), p=0.01), higher body mass index (BMI) (HR 1.07 (1.03–1.10) per unit, p=0.001) and hypertension (HR 3.1 (1.3–7.2), p=0.008). The risk of cardiovascular hospitalisations was higher in both HFrEF (HR 10.3 (5.5–19.4), p<0.001) and HFpEF (HR 6.7 (3.7–12.2), p<0.001). However, only HFrEF was associated with an increased risk of all-cause mortality (HR 5.17 (1.3–19.9), p=0.02) and ventricular tachycardia/fibrillation (HR 64.3 (15.9–259.7), p<0.001).

Conclusion De novo HF occurs in 5.4% of patients with GD and is associated with increased risk of cardiovascular hospitalisations and mortality. Risk factors include AF, higher TRAb, higher BMI and overt hyperthyroidism.