Kaplan-Meier analysis of survival of PMF patients stratified according to the risk categories defined by a clinical-molecular prognostic model. This model includes the variables reported in Table 2, that is, IPSS variables plus CALR, JAK2, and MPL mutation status. We assigned each factor an integer weight according to the corresponding HR in the multivariable-Cox regression of Table 2. Scores were then recoded into the 5 risk categories shown in this figure: details are reported in the last section of “Results.” Based on the Akaike information criterion, which compares quality of models, the clinical-molecular model provided a better stratification than the IPSS. This analysis serves as a proof of concept that accounting for driver mutations improves the risk stratification provided by IPSS.