Multivariable analysis of TE risk. The blood count thresholds of hematocrit (HCT) level >45%, WBC count >11 × 109/L, platelet (PLT) count >400 × 109/L, and absolute neutrophil (NEUT) count >7 × 109/L were assessed in independent models together with the covariates of age, sex, disease duration, and history of TEs and PV-directed therapy. (A) Covariate analysis of blood count values adjacent (in time) to the event identified HCT, WBC, PLT, and NEUT thresholds each independently associated with TEs. (B) Covariate analysis of blood counts above threshold values for a sustained time period (1 year) identified HCT, WBC, and NEUT as independently associated with TEs. The blue lines separating rows demark blood count data that were obtained from independent models. In all models, the significance of the association for the covariates of age, sex, disease duration, history of TE, and treatment with TE risk were unchanged and representative data for these covariates from the HCT level >45% model are shown (data for all models shown in supplemental Figure 2). Significant values (P < .05) are indicated in blue font. Other treatments include ruxolitinib, anagrelide, interferon, busulfan, and chlorambucil. CI, confidence interval.
