Obesity Adversely Affects Survival of Pediatric Patients with Severe Aplastic Anemia After Hematopoietic Cell Transplantation.

Abstract 652

Prevalence of obesity in children has been rapidly rising in the last decade in the US and other industrialized countries (US prevalence, ages 2-19, 16%, NHANES, 2008) and it represents a serious health concern. The impact of recipient's weight on mortality after hematopoietic cell transplantation (HCT) for non-malignant diseases is not well characterized. We studied the effect of body mass (BMI) on transplant outcomes in 1,281 patients aged 2-19 years who underwent HCT for severe aplastic anemia from 1990-2005. The study population was divided in five groups based on age-adjusted BMI percentiles. Patients in the <5^th, 5-25^th, 26-75^th, 76-95^th and >95^th percentile BMI were classified as underweight, at risk for underweight, normal weight, at risk for overweight, and overweight respectively. Cox proportional hazards regression models for survival and acute graft-versus-host disease grade III-IV (aGVHD) were performed using BMI groups as the main effect and the normal weight (26-75^th percentile) as the baseline comparison. Two-year overall survival was lower for overweight children (p<0.001, table). The risk of death, adjusted for significant covariates was higher for overweight compared to normal weight children (p=0.001, table). BMI groups were not associated with excess risk for aGVHD. Other significant factors associated with mortality include race and region of US, donor type, performance score at HCT, recipient age, and year of transplant. Risk of death was higher in African American patients (1.84, p=0.009) compared to Caucasians in the US, donors other than HLA-matched sibling and patients who received HCT before 2002. Among recipients of HLA-matched sibling grafts, use of busulfan-containing regimens (3.13, p<0.001) or cyclophosphamide without antithymocyte globulin (ATG) (1.92, p=0.03) had a higher risk of death compared to recipients of cyclophosphamide and ATG. Conditioning regimens in recipients of unrelated donor HCT were not associated with mortality. Among the reported causes of death, organ failure and infections occurred more frequently in overweight patients compared to the other BMI groups. In conclusion, overweight children with severe aplastic anemia have a higher risk of death after HCT independent of other factors analyzed in the study.