Validation of a Modified Version of the Myeloproliferative Neoplasm Symptom Assessment Form Total Symptom Score

BACKGROUND: Patients with myeloproliferative neoplasms (MPNs) suffer from chronic and progressive symptom burden. MPN trials capturing patient-reported symptoms routinely administer the MPN Symptom Assessment Form (SAF). The MPN-10 assesses 10 of the most clinically relevant symptoms, including fatigue and generates a Total Symptom Score (TSS). The original MPN-10 included a fatigue item from the Brief Fatigue Inventory (BFI). The myelofibrosis-specific symptom assessment tool called the MFSAF v4 utilizes a fatigue item developed to be consistent with other items within the SAF. This study sought to validate a modified version of the MPN-10 TSS using the SAF fatigue item for harmonization with MFSAF v4. METHODS: Survey data from two cohorts of patients with essential thrombocythemia, polycythemia vera, or myelofibrosis assessing MPN characteristics and symptom burden were used. RESULTS AND CONCLUSION: BFI and SAF fatigue items were highly correlated in raw score (Pearson r = 0.88), comparable in their severity categorizations (89% agreement for severe versus non-severe) and respective contributions to the TSS (both Cronbach’s alpha = 0.89). Reliability of SAF fatigue was acceptable and independently associated with known disease-related characteristics (splenomegaly, low quality-of-life, and distress). Fatigue in patients with MPNs is measured with high similarity using the SAF fatigue item within the MPN-10 in harmonization with the MFSAF v4.