Thromboprophylaxis and Risk Factors for Venous Thromboembolism in Critically Ill Children: A Hospital-Based Case-Control Study

Background and objective Critically ill children in pediatric ICUs (PICUs) are at an elevated risk of venous thromboembolism (VTE) due to factors such as central venous catheterization, immobility, and underlying conditions. While thromboprophylaxis is well-established in adult critical care, its use in pediatric populations, particularly in resource-limited settings like Nigeria, remains under-researched and inconsistently applied. This study aimed to evaluate the use, effectiveness, and clinical outcomes of thromboprophylaxis in critically ill pediatric patients and to identify independent predictors of thromboembolic events. Methods A hospital-based case-control study was conducted at Abia State Children's Specialist Hospital, Umuahia, Nigeria, from June 2023 to May 2025. A total of 180 critically ill children aged one month to 18 years were enrolled, comprising 60 cases with imaging-confirmed VTE and 120 age- and sex-matched controls without VTE. Data were collected using a structured case report form from medical records, laboratory and radiological reports, and direct clinical observation. Variables assessed included thromboprophylaxis type (mechanical or pharmacologic), laboratory parameters, and clinical outcomes. Multivariate logistic regression was used to identify independent predictors of VTE. Results Key risk factors for VTE included the presence of central venous catheters (adjusted odds ratio [AOR] = 2.84; p = 0.005), immobility for more than 48 hours (AOR = 2.76; p = 0.005), and BMI above the 95th percentile (AOR = 2.91; p = 0.035). Lack of thromboprophylaxis significantly increased the risk of VTE (AOR = 3.64; p<0.001). Both pharmacologic (p = 0.006) and combined pharmacologic-mechanical (p = 0.011) prophylaxis were associated with significantly reduced odds of VTE compared to no prophylaxis. Children with VTE had longer ICU stays (p<0.001), higher mortality rates (p = 0.010), and were more likely to present with abnormal coagulation profiles and elevated D-dimer levels. Conclusions Thromboprophylaxis, particularly pharmacologic or combined approaches, appears to be effective in reducing VTE among critically ill pediatric patients. However, its utilization remains suboptimal. The implementation of risk-based prophylaxis protocols and early screening strategies is essential to improving outcomes in pediatric critical care, especially in resource-limited settings.