Figure 2

Kaplan-Meier estimates of remaining free of surgery with regard to current disease behaviour. In patients with B1 disease (upper curve), years refer to years after diagnosis in those with stable behaviour, and to years until change of behaviour in those reclassified; In patients with B2 disease (lower curve), years refer to years after diagnosis in cases with stable B2 phenotype, and to years after change of disease behaviour from B1 to B2 in those reclassified; In patients with B3 disease (middle curve), years refer to years after diagnosis in cases with initial B3 phenotype, and to years after change of disease behaviour form B1 or B2 to B3 in those reclassified; The numbers in parentheses (after years from IBD diagnosis) refer to the numbers of patients at risk at the corresponding time points. The corresponding log-rank test p values are: <0.001 (B1 vs B2), <0.001 (B1 vs B3), 0.359 (B2 vs B3).