Abstract
OBJECTIVES: Pulmonary thromboembolism (PTE) is rare but potentially life-threatening in children and differs substantially from adult PTE in epidemiology and risk factors. We conducted a systematic review and meta-analysis to summarise the epidemiology, clinical characteristics and risk factors of paediatric PTE. DESIGN: A systematic review and meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. DATA SOURCES: We searched eight databases (PubMed, Embase (Ovid), MEDLINE (Ovid), Cochrane Library and four Chinese databases) on 2 March 2023, with an updated search on 2 July 2024. ELIGIBILITY CRITERIA: We included original studies reporting epidemiology (incidence/prevalence, major clinical outcomes and long-term sequelae), clinical characteristics, or risk factors of PTE in patients younger than 18 years. Reviews, case reports/series without extractable epidemiological data and studies not focused on paediatric PTE were excluded. DATA EXTRACTION AND SYNTHESIS: Two reviewers independently screened studies, extracted data and assessed risk of bias using appropriate tools for observational studies. A random-effects model was applied to pool prevalence and incidence estimates, along with related outcomes, and their 95% CIs, regardless of the degree of heterogeneity. RESULTS: From 14 438 records, 26 studies were included: 16 cross-sectional, 9 cohort and 1 case-control study. 23 studies were marked as high quality and three as moderate quality. The pooled incidence of paediatric PTE was 0.016% (95% CI 0.0011% to 0.0298%). Autopsy-confirmed prevalence was 5.29% (95% CI 1.28% to 9.30%). Case fatality was 4.04% (95% CI 0.49% to 7.58%), and recurrence was 26.31% (95% CI 19.62% to 33.01%). Available evidence suggested an increasing trend in PTE occurrence over recent years. Female sex and oral contraceptive use were frequently reported clinical characteristics in adolescents. Reported risk factors clustered into genetic predisposition, underlying diseases, immobilisation or surgery and central venous catheter-related thrombosis. CONCLUSIONS: Paediatric PTE remains uncommon but appears to be increasing, with notable recurrence and non-negligible fatality. Given heterogeneous study settings and definitions, further high-quality, population-based studies are needed to refine epidemiological estimates and clarify age-specific risk profiles, thereby informing prevention strategies and clinical management. TRIAL REGISTRATION NUMBER: PREPARE-2023CN922.