Venous Thromboembolism in Pediatric Hematopoietic Cell Transplant: A Multicenter Cohort Study

Venous Thromboembolism in Pediatric Hematopoietic Cell Transplant: A Multicenter Cohort Study
This retrospective study examined the prevalence of venous thromboembolism (VTE) in pediatric patients undergoing a hematopoietic stem cell transplant. To date there has been no large retrospective study to examine both the prevalence and risk factors associated with VTE in this at-risk population.
Utilizing the pediatric health information system; a large database comprising information from 49 US pediatric tertiary care hospitals, ICD-9 codes were used to identify patients who underwent allogeneic or autologous stem cell transplant from January 2010 to September 2014. ICD-9 codes were used to identify VTE events, disease-specific indications for transplant and transplant complications including GVHD up to one-year post transplant.
4,158 eligible patients were identified that underwent a transplant. A total of 209 VTE events were identified, leading to a prevalence of 6.97%. 70% were DVTs, 13% Budd-Chiari syndrome, 9% Pulmonary embolism and 8% portal venous thrombosis. When divided between age groups, the highest prevalence was seen in those 1 month to 1-year-old (12.54%) and patients older than 21 years old (10.31%). Risk factors for VTE were identified as age >13yrs old (OR 1.38; 95%CI 1.08-1.77, p0.01) and allogeneic transplant (OR 1.60; 95%CI 1.19-2.15, p0.01). Finally, patients with VTE had increased length of stay in hospital (81 vs 54 days, p0.01), a median length of stay in the intensive care unit (18 vs 12 days, p0.01) and increased 1-year mortality (13.9% vs 5.9%, p0.01).
This is a retrospective study that depends on ICD-9 coding to correctly identify patients. Certain risk factors for VTE were not analyzed in the data including inherited thrombophilias, or prior history of VTE which would have been helpful information when analyzing the results.
The overall prevalence of VTE in patients undergoing hematopoietic stem cell was 6.97%, which is comparable to previous smaller pediatric studies. The identified age groups for VTE, and risk factors demonstrated by this study may increase awareness of this complication in the post-transplant period.