Fibrinogen levels are associated with bleeding in patients with primary immune thrombocytopenia

Bleeding is the most common clinical symptom and the leading cause of death in patients with primary immune thrombocytopenia (ITP). Our research intends to verify the role of fibrinogen levels as independent determinants of bleeding. We retrospectively analyzed the relationship between fibrinogen levels and bleeding events in 463 patients. Additionally, we confirmed the impact of fibrinogen level on clot firmness in 25 patients via thrombelastography (TEG). Fibrinogen levels (median and inter-quartile range, IQR) were significantly different (p < .001) between bleeding and non-bleeding patients [258(207-314) mg/dL vs. 315(262-407) mg/dL, respectively]. Further analyzes in three subgroups based on platelet (PLT) count showed that non-bleeding patients still had higher fibrinogen levels than bleeding patients. The optimal discriminant threshold of fibrinogen in bleeding was 288.5 mg/dL according to receiver operating characteristic (ROC) curves. Patients were divided into low (LF, 230[193-258] mg/dL) and high (HF, 349[313-424] mg/dL) fibrinogen groups based on this threshold. Bleeding event rates were significantly different (LF: 84.6% vs. HF: 60.4%, P < .001) between the two groups. Multivariable analyses further confirmed these differences. Moreover, TEG parameters showed elevated clot firmness in the HF group. Our data suggest that high fibrinogen levels are associated with reduced bleeding events.