FGF23 and atrial fibrillation: In our sensitivity analysis, when logistic regression with forward selection was applied to all 92 biomarkers in the first 450 patients (discovery cohort), elevated NT-proBNP (precursor fragment of BNP; OR = 1.918 per fold change increase; 95% CI = 1.51–2.94; P = 0.001), and FGF-23 (OR = 1.721 per fold change increase; 95% CI = 1.43–2.45; P = 0.001) were associated with high odds of having AF.