Asthma’s clotting shadow: a meta-analysis unveiling a thrombotic ticking time bomb

OBJECTIVE: To systematically evaluate the association between asthma and the risk of venous thromboembolism (VTE), including pulmonary embolism (PE) and deep vein thrombosis (DVT). DATA SOURCES: PubMed, Embase, Web of Science, and the Cochrane Library were searched for relevant studies published up to May 2025. STUDY SELECTION: Observational studies (cohort, case-control, and cross-sectional) reporting the association between asthma and VTE, PE, or DVT with available odds ratios (ORs) or hazard ratios and 95% confidence intervals (or data to calculate them) were included. RESULTS: The meta-analysis revealed a significant association between asthma and increased risk of VTE. Patients with asthma had a 2.41-fold higher odds of PE (OR = 2.41, 95% CI: 1.77-3.27), 1.56-fold higher odds of DVT (OR = 1.56, 95% CI: 1.49-1.63), and 1.61-fold higher odds of overall VTE (OR = 1.61, 95%: CI 1.45-1.77). Cohort studies showed the strongest association (OR = 4.21, 95% CI 2.56-6.92). Subgroup analysis by region indicated the highest risk in Asia (OR =3.19, 95% CI: 2.06-4.96), followed by America (OR = 2.24, 95% CI: 1.55-3.24) and Europe (OR = 1.64, 95% CI: 1.49-1.81). CONCLUSION: Asthma is significantly associated with an elevated risk of PE, DVT, and VTE, with particularly strong associations observed in cohort studies and Asian populations. These findings highlight the need for further research into underlying mechanisms and whether optimized asthma management can reduce thrombotic risk.