VWF and von Willebrand disease 1: Subsequently, in a meta-analysis of in patients with VWD type 1 [12], VWF:Ag (OR, 1.055 per U/dL; 95% CI 1.016–1.096), VWF activity (several assays included; OR, 1.048 per U/dL; 95% CI, 1.008–1.090 (noting the majority of VWF activity assays comprised VWF:RCo but others were assessed with different platelet binding assays), and FVIII coagulant (FVIII:C) (OR, 1.023 per U/dL; 95% CI 1.002–1.045) were associated with a higher proportion of complete response, whereas age and VWF collagen binding (VWF:CB) assays were not [12].