Figure 1

(a–d) Kaplan–Meier estimates of fibrosis-free survival and overall survival with significant differences in 232 WHO-confirmed versus 238 BCSH-defined ET patients (Figures a and b). Separate analysis of the WHO-diagnosed prePMF fraction of 77 patients included in the BCSH-classified ET cohort of 238 patients reveals a significant worsening of fibrosis-free and overall survival (Figures c and d). Abbreviation: CI, confidence interval.