Prognostic significance of delayed thrombocytopenia after allogeneic stem cell transplant

Previous studies showed that late-onset thrombocytopenia is a strong negative prognostic indicator of survival in allogeneic hematopoietic stem cell transplant (SCT) recipients and, in particular, in those cases where thrombocytopenia is related to chronic graft versus host disease (cGVHD) [1-12]. To investigate this issue, 71 adult patients who survived for >= 3 months with median follow-up time of 21 months (range, 3-44 months) after SCT were evaluated. Twenty-seven patients (38%) developed thrombocytopenia with a median platelet count of 29 x 10(9)/L. Patients with and without thrombocytopenia had similar baseline clinical characteristics, transplant type, and status at transplant. The incidence of mortality was significantly higher in patients with post-SCT thrombocytopenia (70% vs. 14%; P < 0.0001). The principal causes of mortality in this group were primary disease (58%), cGVHD (16%) and infections (10.5%). In multivariate analysis only thrombocytopenia was significantly associated with overall survival (HR 9.77; 95% CI, 3.63-26.33; P < 0.0001). Thirty-two patients developed cGVHD and 13 had concomitant thrombocytopenia. The incidence of mortality was significantly higher in patients with post SCT thrombocytopenia compared with patients without thrombocytopenia (61.5% vs. 10.5%; P = 0.005). The occurrence of post-SCT thrombocytopenia appears to be a strong negative predictor of survival.