Predictive value of NLR for thrombotic risk in prefibrotic primary MF: INFLA-ME sub-analysis

Results from a sub-analysis of the multicenter, retro-prospective observational INFLA-ME study (NCT05553873), investigating the prognostic value of neutrophil-to-lymphocyte ratio (NLR) for thrombotic risk in patients with prefibrotic primary myelofibrosis (prePMF), were published in Annals of Hematology by Cavalca et al. The study included 225 patients with prePMF diagnosed according to the 2022 World Health Organization (WHO) criteria and followed across eight Italian hematology centers. The primary endpoint was to evaluate the association between NLR at diagnosis and the risk of thrombotic events during follow-up.  

Key data: With a median follow-up of 5.9 years, 37 thrombotic events were reported; the overall thrombotic event rate was 2.5 events per 100 patients/year, comprising 18 arterial and 19 venous events. On multivariate analysis, venous thrombosis risk was significantly associated with a history of prior venous thrombosis (hazard ratio [HR], 4.46; 95% confidence interval [CI], 1.79–11.11; p = 0.001) and with an NLR ≥6 at diagnosis (HR, 3.82; 95% CI, 1.42–10.29; p = 0.008). Patients with NLR ≥6 experienced a significantly shorter venous thrombosis-free survival (TFS) compared with those with NLR <6 (p = 0.003). No significant association was observed between NLR and total or arterial thrombotic events. 

Key learning: Baseline NLR at diagnosis was identified as an independent predictor of venous thrombosis in patients with prePMF, highlighting the prognostic potential of inflammatory biomarkers beyond conventional risk models. These findings support the possible incorporation of NLR into existing thrombotic risk stratification approaches to better identify patients with prePMF who may benefit from earlier cytoreductive intervention.