Association between VWF, VWFpp, and VWF:FVIIIB and FVIII half-life. The Pearson correlation coefficient of continuous variables was assessed by a 2-tailed test of significance. (A) Strong positive correlation between VWF:Ag and FVIII half-life (P < .0001). (B) Weak positive correlation between VWFpp (a surrogate marker for VWF secretion) and FVIII half-life (P = .202). (C) Moderate negative correlation between VWFpp/VWF:Ag ratio (a surrogate marker for VWF clearance) and FVIII half-life (P < .0001). (D) Moderate positive correlation between VWF:FVIIIB and FVIII half-life (P = .0012).