OS and LFS in relation to diagnosis and IPSS risk categories in study patients population. (A-B) The Kaplan-Meier estimate of OS (A) and LFS (B) in patients with pre-MF and overt PMF using competitive risk analysis for disease-related deaths. The difference between the 2 patient populations was statistically significant at P < .0001 for OS and P = .001 for LFS. For comparison, OS and LFS curves of a population of 421 WHO 2016-defined patients with ET are also shown. (C-D) The Kaplan-Meier estimate of OS according to the 4 risk categories (low, intermediate-1, intermediate-2, high risk) in which the patients with pre-PMF (C) and overt PMF (D), respectively, were stratified at diagnosis according to the IPSS criteria. Overall, the curves were significantly different at P < .0001.