Late Mortality after Allogeneic Bone Marrow Transplantation in Childhood for Bone Marrow Failure Syndromes and Severe Aplastic Anemia

Abstract

Children with bone marrow failure syndromes and severe aplastic anemia (SAA) are treated with allogeneic blood or marrow transplantation (BMT). However, there is a paucity of studies examining late mortality risk after allogeneic BMT performed in childhood for bone marrow failure syndromes and SAA and evaluating how this risk differs between these diseases. We investigated cause-specific late mortality in 2-year survivors of allogeneic BMT for bone marrow failure syndromes and SAA performed before age 22years between 1974 and 2010 at 2 US transplantation centers. Vital status information was collected from medical records, the National Death Index, and Accurint databases. Overall survival was calculated using Kaplan-Meier techniques. The standardized mortality ratio (SMR) was calculated using age- sex-, and calendar-specific mortality rates from the Centers for Disease Control and Prevention. Among the 2-year survivors of bone marrow failure syndromes (n = 120) and SAA (n = 147), there were 15 and 19 deaths, respectively, yielding an overall survival of 86.4% for bone marrow failure syndromes and 93.1% for SAA at 15years post-BMT. Compared with the general population, patients with bone marrow failure syndromes were at a higher risk for premature death (SMR, 22.7; 95% CI, 13.1 to 36.2) compared with those with SAA (SMR, 4.5; 95% CI, 2.8 to 7.0) (P < .0001). The elevated relative risk persisted at ≥15years after BMT for both diseases. The hazard of all-cause late mortality was 2.9-fold (95% CI, 1.1 to 7.3) higher in patients with bone marrow failure syndromes compared with those with SAA. The high late mortality risk in recipients of allogeneic BMT in childhood for bone marrow failure syndromes calls for intensified life-long follow-up.