Thyroid dysfunction in nonvalvular atrial fibrillation and clinical outcomes

Thyroid dysfunction’s effects on those who have been diagnosed with atrial fibrillation have not been well investigated. We looked at how thyroid function among patients with pre-existing atrial fibrillation related to thromboembolic risk and clinical outcomes.

We gathered the medical information of patients diagnosed with nonvalvular atrial fibrillation (NVAF) between 2016 and 2020 at Dongguan People’s Hospital. We then assessed the correlation between thyroid dysfunction and thrombotic risk (CHA₂DS₂-VASc) as well as the occurrence of clinical composite endpoint (all-cause death, heart failure, systemic embolism and hemorrhage events).

Of 1329 patients were admitted, 82.6% were euthyroid, 7.4% had subclinical hyperthyroidism, 4.2% had subclinical hypothyroidism, and 6.7% had low triiodothyronine (T3) syndrome. Lower levels of total triiodothyronine (TT3) were linked to an increased risk of thromboembolism (P < 0.005). During a median follow-up period of 1.84 years, there were 608 clinical composite endpoint occurrences. In the adjusted model, Low T3 syndrome was linked to a higher risk of the clinical composite endpoint (HR, 1.68; 95% CI, 1.20–2.37; P < 0.05) in comparison to euthyroidism. Specifically, low T3 syndrome was linked to a higher risk of heart failure (HR, 1.52; 95%CI, 1.01–2.30; P < 0.05) and all-cause death (HR, 3.34; 95% CI, 1.76–6.36; P < 0.001).

Low T3 syndrome are linked to an increased risk of heart failure and all-cause death in individuals with NVAF. And Patients with NVAF and low TT3 levels have a higher risk of thromboembolism.