Haemostatic Dysfunction in Lassa Fever: Implications for Disease Severity and Outcome

Background: Lassa fever is a viral haemorrhagic illness endemic to Nigeria and other West African countries. Severe cases are often associated with abnormal coagulation and impaired platelet function. Objective: This study primarily assessed coagulation parameters and examined their correlation with clinical outcomes in patients with acute Lassa fever. Patients and Methods: This hospital-based case-control study included 324 participants: 108 Lassa virus-positive patients, 108 febrile Lassa-negative patients (Control 1), and 108 afebrile Lassa-negative individuals (Control 2). Prothrombin time (PT) and activated partial thromboplastin time (APTT) were measured using standard methods. Fibrinogen and D-dimer levels were determined via a sandwich enzyme-linked immunosorbent assay technique. Results: Mean PT and APTT were significantly higher in the Lassa-positive group compared with both control groups (PT: p < 0.001; APTT: p = 0.048). Prolonged coagulation times were observed in 23 of 108 (21.3%) patients with Lassa fever (p < 0.001). Median fibrinogen levels (mg/dL) were lower in patients with Lassa fever [272.65 (interquartile range (IQR): 204.8–366.8)] than in Control 1 [335.55 (258.5–398.6)] and Control 2 [306.90 (245.6–355.2)], with statistically significant differences (p < 0.001). Median D-dimer levels (ng/mL) were elevated in patients with Lassa fever [1054.00 (593–1588)] compared with Control 1 [325.50 (173–715)] and Control 2 [188.00 (145–273)] (p < 0.001). Conclusions: Lassa fever is associated with significant alterations in coagulation parameters. Patients with acute Lassa infection showed elevated PT, APTT, and D-dimer levels, along with decreased fibrinogen levels, compared with controls. These findings underscore the role of coagulopathy in the pathogenesis and severity of Lassa fever.