Abstract
Background Venous thromboembolism (VTE) is a major vascular disease associated with substantial morbidity and mortality worldwide. Chronic low-grade systemic inflammation has been implicated in thrombus formation, yet its long-term association with incident VTE in the general population remains incompletely understood using routinely available biomarkers. Methods We conducted a prospective cohort analysis of 473,717 participants from the UK Biobank to examine associations between baseline inflammatory biomarkers - including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), systemic immune-inflammation index (SII), and systemic inflammation response index (SIRI) - and incident hospitalized VTE. Inflammatory biomarkers were measured at baseline (2006-2010), and hospitalized VTE events were identified through linked hospital inpatient records using ICD-10 codes during follow-up. Cox proportional hazards regression models were used to estimate associations between inflammatory biomarkers and incident hospitalized VTE, with hazard ratios (HRs) calculated per unit increase based on baseline blood cell counts. Results During a median follow-up of 14.6 years, 13,709 participants developed hospitalized VTE, including 12,291 pulmonary embolism events, 1,168 deep vein thrombosis events, and 250 cases with both conditions. Higher baseline neutrophil count, monocyte count, and NLR were independently associated with incident hospitalized VTE after multivariable adjustment. Associations for composite indices such as SII and SIRI were attenuated after accounting for shared cellular components and clinical confounders. The observed VTE incidence was lower than population-based estimates, reflecting reliance on hospital inpatient records that preferentially capture clinically significant events. Conclusion Baseline low-grade systemic inflammation is associated with the long-term risk of hospitalized VTE in the general population. Despite conservative event ascertainment, routinely measured inflammatory biomarkers - particularly NLR and monocyte count - remained independently associated with future events, supporting their potential role as complementary markers for long-term VTE risk stratification and prevention.</p>