Lekovic, Danijela (36659562000)Danijela (36659562000)LekovicBogdanovic, Andrija (6603686934)Andrija (6603686934)BogdanovicSobas, Marta (24175076400)Marta (24175076400)SobasArsenovic, Isidora (58551558700)Isidora (58551558700)ArsenovicSmiljanic, Mihailo (45661914300)Mihailo (45661914300)SmiljanicIvanovic, Jelena (58551445800)Jelena (58551445800)IvanovicBodrozic, Jelena (55895034400)Jelena (55895034400)BodrozicCokic, Vladan (6507196877)Vladan (6507196877)CokicMilic, Natasa (7003460927)Natasa (7003460927)Milic2025-07-022025-07-022023https://doi.org/10.3390/cancers15164180https://www.scopus.com/inward/record.uri?eid=2-s2.0-85168894260&doi=10.3390%2fcancers15164180&partnerID=40&md5=4aa5f3be3bc33852cb71d56f98669056https://remedy.med.bg.ac.rs/handle/123456789/11818Essential thrombocythemia (ET) and prefibrotic primary myelofibrosis (prePMF) initially have a similar phenotypic presentation with thrombocytosis. The aim of our study was to determine significant clinical-laboratory parameters at presentation to differentiate prePMF from ET as well as to develop and validate a predictive diagnostic prePMF model. This retrospective study included 464 patients divided into ET (289 pts) and prePMF (175 pts) groups. The model was built using data from a development cohort (229 pts; 143 ET, 86 prePMF), which was then tested in an internal validation cohort (235 pts; 146 ET, 89 prePMF). The most important prePMF predictors in the multivariate logistic model were age ≥ 60 years (RR = 2.2), splenomegaly (RR = 13.2), and increased lactat-dehidrogenase (RR = 2.8). Risk scores were assigned according to derived relative risk (RR) for age ≥ 60 years (1 point), splenomegaly (2 points), and increased lactat-dehidrogenase (1 point). Positive predictive value (PPV) for pre-PMF diagnosis with a score of ≥points was 69.8%, while for a score of ≥3 it was 88.2%. Diagnostic performance had similar values in the validation cohort. In MPN patients with thrombocytosis at presentation, the application of the new model enables differentiation of pre-PMF from ET, which is clinically relevant considering that these diseases have different prognoses and treatments. © 2023 by the authors.differential diagnosisessential thrombocythemia (ET)predictive modelprefibrotic primary myelofibrosis (pre-PMF)