Effect of body mass index on the outcome of children with acute myeloid leukemia

Abstract

Background: The effect of body mass index (BMI) on the treatment outcomes of children with acute myeloid leukemia (AML) is unclear and needs further evaluation.

Methods: Children with AML (n = 314) who were enrolled in 4 consecutive St. Jude protocols were grouped according to BMI (underweight, <5th percentile; healthy weight, 5th to 85th percentile; and overweight/obese, ≥ 85th percentile).

Results: Twenty-five patients (8%) were underweight, 86 patients (27.4%) were overweight/obese, and 203 patients (64.6%) had healthy weight. The 5-year overall survival rate of overweight/obese patients (46.5% ± 7.3%) was lower than the rate of patients with healthy weight (67.1% ± 4.3%; P < .001); underweight patients also tended to have lower survival rates (50.6% ± 10.7%; P = .18). In a multivariable analysis that was adjusted for age, leukocyte count, French-American-British classification, and study protocols, patients with healthy weight had the best survival rate among the 3 groups (P = .01). When BMI was considered as continuous variable, patients with lower or higher BMI percentiles had worse survival (P = .03). There was no difference in the occurrence of induction failure or relapse among BMI groups, although underweight and overweight/obese patients had a significantly higher cumulative incidence of treatment-related mortality, especially because of infection (P = .009).

Conclusions: An unhealthy BMI was associated with worse survival and more treatment-related mortality in children with AML. Meticulous supportive care with nutritional support and education, infection prophylaxis, and detailed laboratory and physical examination is required for these patients. These measures, together with pharmacokinetics-guided chemotherapy dosing, may improve outcome.

Figure 1

Overall survival (A) and event-free survival (B) of 314 children with acute myeloid leukemia. Data were analyzed with patients classified into 3 groups of body mass index: underweight, healthy weight, overweight/obese.

Figure 2

Association between BMI percentile and overall survival (OS, A and C) and event-free survival (EFS, B and D). Data were analyzed with Cox regression on BMI percentile as a continuous variable in a spline model, stratified by study protocol (A and B). In multivariable analysis, OS and EFS were modeled in the Cox proportional hazard regression with age, leukocyte count and FAB type as class predictor variables and BMI percentile as a continuous variable in a spline model, stratified by study protocol (C and D). In each panel, black line shows smoothing spline fit and gray lines show ±1 standard errors.

Figure 3

Cumulative incidence of grade 2 or higher infections (A), grade 3 or higher infections (B), and grade 4 infections (C). Data were analyzed after patients were classified into 3 groups of body mass index: underweight, healthy weight, overweight/obese.

Figure 4

Cumulative incidence of treatment-related mortality in 314 children with acute myeloid leukemia. Data were analyzed with patients were classified into 3 groups of body mass index: underweight, healthy weight, overweight/obese.