Distinct clustering of symptomatic burden among myeloproliferative neoplasm patients: retrospective assessment in 1470 patients.

Symptom burden in myeloproliferative neoplasms (MPNs) is heterogeneous even among patients within the same MPN diagnosis. Using cluster analysis from prospectively gathered symptom burden data in 1470 international patients with essential thrombocythemia (ET), polycythemia vera (PV), or myelofibrosis (MF), we assessed for the presence of clusters and relationship to disease features and prognosis. In MF (4 clusters identified), clusters significantly differed by Dynamic International Prognostic Scoring System (DIPSS) risk (P < .001), leukopenia (P = .009), thrombocytopenia (P < .001), and spleen size (P = .02). Although an association existed between clusters and DIPSS risk, high symptom burden was noted in some low and intermediate-1-risk MF patients. In PV (5 clusters identified), total symptom score increased across clusters (P < .001), but clusters did not significantly differ by PV risk or the risk assessment variable of age. Among ET patients (5 clusters identified), clusters differed by gender (P = .04), anemia (P = .01), and prior hemorrhage (P = .047). Total symptom score increased across clusters (P < .001), but clusters did not significantly differ by International Prognostic Score for ET risk including the risk assessment variables. Significant symptom heterogeneity exists within each MPN subtype, sometimes independent of disease features or prognosis.