Kaplan-Meier analysis of survival and cumulative incidence of relapse following allogeneic HSCT in MDS patients stratified according to their pretransplant IPSS or IPSS-R risk. (A) No significant difference in posttransplant OS was observed between low and intermediate-1 IPSS risk (P = .61) and between intermediate-2 and high IPSS risk (P = .16). By contrast, there was a significant difference in posttransplant OS between low or intermediate-1 and intermediate-2 or high IPSS risk (P < .001). (B) Patients with low or intermediate-1 IPSS risk also showed a lower probability of relapse than those with intermediate-2 or high IPSS risk (P < . 001). (C) No significant difference in posttransplantation OS was observed between low and intermediate IPSS-R risk (P = . 17). There was a significant difference in post-transplant OS between low or intermediate IPSS-R risk and high or very high IPSS-R risk (P = .01 and P < .001, respectively) and also between high and very high IPSS-R risk (P < .001). (D) Patients with low or intermediate IPSS-R risk also showed a lower probability of relapse than those with high or very high IPSS-R risk (P = .01 and P < .001, respectively), whereas patients with very high risk showed a higher probability of relapse than those with high risk (P < .001).