Secondary hyperparathyroidism in adult congenital heart disease: the CHD-HYPER-study.

Aims: In non-congenital heart disease, secondary hyperparathyroidism (sHPT) is associated with an elevated risk of new-onset heart failure (HF) and an increased incidence of HF-related hospitalizations. Yet, for adults with congenital heart disease (ACHD), the role of sHPT and the factors contributing to its development remain poorly understood. Methods and results: This cross-sectional, single-centre study assessed the prevalence of sHPT in 754 patients with ACHD. Independent predictors of sHPT were identified in both, within the entire cohort and specifically in ACHD with biventricular physiology. Findings: We found a high prevalence of sHPT in ACHD at 14.9%, with the highest rates in patients with Eisenmenger syndrome/PAH-CHD (39.1%), Ebstein's anomaly (29.2%), Fontan palliation (25%), and pulmonary atresia (25%). SHPT was more common in patients with univentricular physiology (29.6%) than biventricular physiology (13.3%) (P < 0.001). In multivariate analysis, glomerular filtration rate (P < 0.001), serum 25-hydroxyvitamin D₃ (P = 0.004), use of loop diuretics (P = 0.001), oxygen saturation (P = 0.03), and liver stiffness (P = 0.033) were independently associated with sHPT. Among patients with biventricular physiology, right ventricular free wall longitudinal strain (P = 0.028)-rather than left ventricular global longitudinal strain-showed a significant association with the presence of sHPT. Conclusion: sHPT is observed across the spectrum of ACHD but is more common in patients with complex and more severe disease, particularly those with predominant right heart involvement.