Body mass index and its effect on outcome in children after lung transplantation

Background: Malnutrition is common in children undergoing lung transplantation, particularly among those with cystic fibrosis (CF). However, the effect of body habitus on outcome after pediatric lung transplantation is unknown. We studied body mass index (BMI) and its effect on outcome in pediatric lung transplantation.

Methods: The International Society for Heart and Lung Transplantation Registry on Pediatric Lung Transplantation was queried for primary pediatric lung transplant recipients (aged<18 years) between 1990 and 2008. BMI cohorts were defined according to International Obesity Task Force cutoffs: thinness grade 3, BMI<16 kg/m(2); thinness grade 2, 16 to<17 kg/m(2); thinness grade 1, 17 to<18.5 kg/m(2); normal, 18.5 to<25 kg/m(2); overweight, 25 to<30 kg/m(2); and obese, ≥ 30 kg/m(2). Survival was compared among BMI cohorts within CF and non-CF recipient groups.

Results: Included were 897 recipients. The median age at transplantation was 14 years (interquartile, 11, 16 years) and 63% had CF. The incidence of thinness was 59% in CF vs 39% in non-CF patients (p<0.001). A significant proportion of CF patients were underweight, whereas more non-CF patients were obese. Cox regression showed neither underweight nor overweight CF recipients differed in survival compared with recipients of normal-weight recipients. Grade of thinness was not related to outcome after transplantation. For non-CF recipients, being overweight/obese increased risk of death compared with normal-weight recipients (hazard ratio, 2.05; 95% confidence interval, 1.28-3.26; p = 0.002).

Conclusion: The incidence of underweight status amongst pediatric lung transplant recipients with CF is high. However, we did not find a significant negative effect of underweight body habitus on survival in CF children after lung transplantation. Overweight pediatric recipients appear to have poorer survival after transplant.