Thyroid parameters (PTFQI, TSH, and fT4) of a sample of patients with atrial fibrillation were compared to a reference sample of healthcare patients (case-control study). Patients with atrial fibrillation (paroxistic or persistent) who required, at least, one hospital admission were included as cases. The control sample PTFQI distribution tertiles were used as cut-offs for dividing cases and controls. We compared atrial fibrillation odds across the tertiles.
Within the cases sample, additionally, a cross-sectional study of association of the thyroid parameters with clinical characteristics was conducted (cross-sectional study).
We reviewed the 165 clinical records of the patients with atrial fibrillation who were admitted to the Miguel Servet University Hospital in Zaragoza (Spain) from July 2017 to June 2019. Exclusion criteria included previous thyroid disease or abnormal TSH and fT4 (which was the main cause of exclusion, 72%) and diseases or pharmacological treatments that interfere with the thyroid axis, among which amiodarone use accounted for the 35% of excluded pacients (Supplementary Material Table 1). Only patients who had TSH and fT4 values available before medical intervention (electrical cardioversion, catheter ablation, or treatment with amiodarone) were included. The number of patients identified for the analysis was 84 (Supplementary Material Figure 1).
Thyroid parameters of healthcare patients older than 18 years who underwent a thyroid hormone measurement across three months of 2018, in the central laboratory of the Miguel Servet University Hospital (6051 patients) were used to calculate the reference parameters for the PTFQI formula (14 (link)). Euthyroid participants of this sample constituted the control group (n=5256).
This study protocol was approved by the Ethical Committee of Clinical Research of Aragón (CEICA) (expedient numbers 19-041 and 19-519) who authorized review of clinical records.
Free full text: Click here