Kaplan-Maier curves showing the percentage of patients not having experienced these occurrences, according to mutation groups. First bleed (A), first joint bleed (B), and second joint bleed (C). Shown below each of the panels is the number of patients censored step by step at each of the age groups shown on the x-axis. In each analysis, patients who started prophylaxis before the bleeding event were censored. The Log-rank test showed a significant difference (P = .028) in age at first bleed between patients with null mutations and those with non-null mutations. For age at first joint bleed and age at second joint bleed, the Log-rank test was not statistically different between the 3 groups with P values of 0.18 and 0.26, respectively.