Statistical Analysis
Sample size was determined by the accrual time period. Due to our
relatively small sample size (N=23), robust nonparametric statistical
methods were used for data analysis. The continuous variables were
summarized by median, minimum, and maximum and the categorical variables
were summarized by frequency and rates. At each visit timepoint, boxplot
was used to illustrate the distribution of the median BMI z-score
overall and within subgroups. The Friedman’s test was used to examine if
there is any significant difference in median BMI z-score across the
three timepoints, the Fisher’s exact test was used to examine the
difference in BMI categories for the three visits, and the Wilcoxon rank
sum test was used for comparison of BMI z-score between groups at each
visit time point. The Friedman’s test was also used to examine the
change of dietary intake and diet quality over time. The Wilcoxon signed
rank test was performed to investigate the change of dietary intake and
diet quality between study entry and end of month six. Median regression
analysis was used to evaluate the relationship between change in dietary
factors and change in BMI z-score from study entry to end of induction
or end of month six after adjustment of age, gender, ethnicity, and BMI
z-score at study of entry. The R 4.0 and SAS 9.4 (Cary, NC) were used
for data analysis.
RESULTS
Twenty-eight participants enrolled in the study between June 2017
through August 2019. Two participants withdrew due to feeling too
overwhelmed by the diagnosis of ALL and three withdrew due to reluctance
to complete study assessments; all withdrew within the first two months.
Two additional participants were removed from the study prior to end of
month six due to change in institution and clinical course, and thus did
not receive the full intervention. The analysis represents 23 (82.1%)
evaluable participants.
The demographic and clinical characteristics are presented in Table 1.
The cohort reflected the demographics of childhood ALL with slightly
more males (52.2%) than females (47.8%); 43.5% were Hispanic and
52.2% were white. Nearly 22% of participants were classified as obese
at study entry; higher than previously reported studies in
ALL.6,22 Most participants (82.6%) selected to
initiate nutrition counseling at study entry. Of the four participants
who elected to initiate nutrition counseling (N=4) later in the
induction phase of treatment, the majority were female (75%),
Non-Hispanic and white (75%), and younger (less than 10 years old)
(75%).