Kaplan-Meier analysis of survival without inhibitor period. The curves were plotted for each end point (from the left to the right: all inhibitors, high inhibitors, high inhibitors and/or ITI) and cofactors (from the top to the bottom: product, F8 genotype, ethnicity, family history of inhibitor, age at first infusion). The number of patients at risk for each cumulative exposure day is given at the bottom.