ADAMTS13 and atrial fibrillation: We found significantly lower risks of new-onset AF in patients with VWF ≥ median (1.39 IU/mL), with a HR of 0.5 (95% CI, 0.3-1.0; P = .04); VWF/ADAMTS-13 ag ≥ median (2.04 × 10−3 IU/ng), with a HR of 0.5 (95% CI, 0.3-1.0; P = .05); and VWF/ADAMTS-13 act ≥ median (1.76), with a HR of 0.4 (95% CI, 0.2-0.7; P = .004).