Prognostic Relevance of Thyroid Disorders in Adults With Congenital Heart Disease

Adults with congenital heart disease (ACHD) are frequently affected by thyroid diseases (TDs). However, the clinical relevance of TD in ACHD remains unknown. We aimed to describe the prevalence of TD in the ACHD population and to ascertain whether TD are associated with worse outcome. Patients with ACHD >18 years attending our tertiary center for a day-case between 2014 and 2019 were included. Clinical data between patients' first visit and December 2020 were collected. Primary end point was a combination of death, hospitalization for heart failure (HF), and new-onset of arrhythmic events. Secondary end points were each part of the primary outcome as separate end points. A total of 495 patients with ACHD (32.2 [24.5 to 45.6] years; 54% women) were included. Median follow-up was 9.4 (4.5 to 13.1) years. The prevalence of TD was 30%. TD group showed worse clinical status, as demonstrated by N-terminal pro b-type natriuretic peptide values (243.5 [96.5 to 523] vs 94 [45 to 207] pg/ml, p <0.001) and New York Heart Association class (27% vs 13% in class III to IV, p <0.0001) with higher incident rate of adverse events at follow-up (4.45 [3.43 to 5.69] % vs 1.29[0.94 to 1.75] % per person-year, p <0.001). TD were independently associated with higher risk of death (hazard ratio [HR] 4.1, p = 0.009), arrhythmic events (HR 3.8, p <0.0001), and hospitalization for HF (HR 8.02, p <0.0001). There was a fourfold increased risk of primary end point in the TD group even after propensity score matching for clinical variables including age, gender, disease complexity, physiological stage, previous palliative surgery, ventricular function, pulmonary arterial hypertension, cyanosis, and presence of systemic right ventricle (HR 4.47, p <0.0001). In conclusion, TD are predictive of adverse outcome in the ACHD population. Routine screening of thyroid function during follow-up in this population may be helpful to identify those with higher risk of death, arrhythmias, and HF.