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

Hematopoietic cell transplant (HCT) is associated with a proinflammatory, procoagulant environment that places recipients at increased risk of venous thromboembolism (VTE). Although the incidence of VTE in adult HCT recipients has been extensively studied, similar data for children are lacking. We conducted a multicenter retrospective study to analyze the prevalence of VTE and associated risk factors in a large cohort of patients who underwent HCT at tertiary care US children's hospitals. The Pediatric Health Information System database, a large administrative database that contains clinical and resource utilization data from 49 freestanding children's hospitals in the United States, was used to extract data. International Classification of Diseases, Ninth Revision, Clinical Modification codes were used to identify HCT recipients, VTE events, post-HCT complications, and associated risk factors up to 1 year post-transplant. Data on patients who received HCT from January 2010 through September 2014 were collected. A total of 4158 unique patients mean ± standard deviation age at transplant admit, 8.8 ± 6.5 years; range, birth to 33.4 years) were identified. After HCT 290 subjects (6.9%) developed VTE. VTE prevalence was greater in patients aged ≥ 13 versus <13 years (8.54% versus 6.33%; P = .01) and in recipients of allogeneic versus autologous grafts (7.7% versus 5%; P ≤ .01). VTE was associated with prolonged median duration of hospitalization (81 versus 54 days; P ≤.01) and increased 1-year mortality (13.9% versus 5.9%; P ≤ .01). Infections and presence of any graft-versus-host disease (GVHD) were significantly associated with VTE occurrence in recipients of allogenic grafts. Prevalence of VTE in patients who underwent HCT at pediatric tertiary care hospitals is about 7%. Age ≥ 13 years and allogeneic grafts were significant pre-HCT VTE risk factors, with GVHD and infections seen more frequently in patients with VTE.