Effectiveness of a Hospital-Based Multidisciplinary Pediatric Weight Management Program: Two-Year Outcomes of PHIT Kids

Hampl, Sarah; Stough, Cathleen Odar; Cordts, Katrina M. Poppert; Best, Cora M.; Blackburn, Katherine; Gillette, Meredith L. Dreyer

doi:10.1089/chi.2014.0119

Cited by 31 publications

(35 citation statements)

References 25 publications

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“…The attenuation and confounding of very high BMIz values could be particularly problematic in longitudinal studies that focus on children with obesity (8,26–28,32). As these children age during follow-up, the extent of the compression of very high BMIz values will vary based on the values of L and S in the growth charts.…”

Section: Discussionmentioning

confidence: 99%

The Limitations of Transforming Very High Body Mass Indexes into z -Scores among 8.7 Million 2- to 4-Year-Old Children

Freedman

Butte

Taveras

et al. 2017

The Journal of Pediatrics

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Objective To examine the associations among several BMI metrics (z-scores, percent of the 95th percentile (%BMIp95) and ΔBMIp95 (BMI minus 95th percentile) as calculated in the CDC growth charts. It is known that the widely-used BMI z-scores and percentiles calculated from the growth charts can differ substantially from those that directly observed in the data for BMIs above the 97th percentile (z = 1.88). Study design Cross-sectional analyses of 8.7 million 2- to 4-year-olds who were examined from 2008 through 2011 in the CDC’s Pediatric Nutrition Surveillance System. Results Because of the transformation used to calculate z-scores, the theoretical maximum BMIz varied by more than 3-fold across ages. This results in the conversion of very high BMIs into a narrow range of z-scores that varied by sex and age. Among children with severe obesity, levels of BMIz were only moderately correlated (r ~ 0.5) with %BMIp95 and ΔBMIp95. Among these children with severe obesity, BMIz levels could differ by more than 1 SD among children who had very similar levels of BMI, %BMIp95 and ΔBMIp95 due to differences in age or sex. Conclusions The effective upper limit of BMIz values calculated from the CDC growth charts, which varies by sex and age, strongly influences the calculation of z-scores for children with severe obesity. Expressing these very high BMIs relative to the CDC 95th percentile, either as a difference or percentage, would be preferable to using BMI-for-age, particularly when assessing the effectiveness of interventions.

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Section: Discussionmentioning

confidence: 99%

The Limitations of Transforming Very High Body Mass Indexes into z -Scores among 8.7 Million 2- to 4-Year-Old Children

Freedman

Butte

Taveras

et al. 2017

The Journal of Pediatrics

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“…Although the report for the CDC growth charts (Kuczmarski et al, 2002) cautioned about extrapolating outside the 3rd and 97th percentiles of BMI, BMI z remains widely used in studies that include large numbers of children with very high BMIs (Hampl et al, 2016; Kreier et al, 2013; McCormick et al, 2014; Smego et al, 2017; Wang et al, 2015). We have shown that, among children with severe obesity, BMI z levels are only weakly associated with other measures of body size (Freedman et al, 2017a) and the current results highlight the drawbacks of attempting to assess longitudinal BMI z changes.…”

Section: Discussionmentioning

confidence: 99%

“…Extrapolated z -scores based on the CDC growth charts are widely used among children who have very high BMIs (Baughcum et al, 2015; Hampl et al, 2016; Kreier et al, 2013; Smego et al, 2017; Wang et al, 2015). However, BMI z values for extremely high BMIs can differ substantially from the empirical estimates (Flegal et al, 2009), have an effective upper limit (Woo, 2009) and are strongly influenced by sex and age.…”

Section: Discussionmentioning

confidence: 99%

Longitudinal changes in BMIz-scores among 45 414 2–4-year olds with severe obesity

Freedman

Butte

Taveras

et al. 2017

Annals of Human Biology

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Background BMI z-scores (BMIz) based on the Centers for Disease Control and Prevention (CDC) growth charts among children do not accurately characterise BMI levels among children with very high BMIs. These limitations may be particularly relevant in longitudinal and intervention studies, as the large changes in the L (normality) and S (dispersion) parameters with age can influence BMIz. Aim To compare longitudinal changes in BMIz with BMI expressed as a percentage of the 95th percentile (%BMIp95) and a modified z-score calculated as log(BMI/M)/S. Subjects and methods A total of 45 414 2–4-year-olds with severe obesity (%BMIp95 ≥ 120). Results Changes in very high BMIz levels differed from the other metrics. Among severely obese 2-year-old girls, for example, the mean BMIz decreased by 0.6 SD between examinations, but there were only small changes in BMIp95 and modified BMIz. Some 2-year-old girls had BMIz decreases of >1 SD, even though they had large increases in BMI, %BMIp95 and modified BMIz. Conclusions Among children with severe obesity, BMIz changes may be due to differences in the transformations used to estimate levels of BMIz rather than to changes in body size. The BMIs of these children could be expressed relative to the 95th percentile or as modified z-scores.

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“…However, BMI z ‐scores have been shown to be an inadequate and possibly biased measure of adiposity in children with severe obesity because a wide range of high BMI values corresponds to a relatively narrow range of BMI z ‐scores in an age‐dependent way . Despite this well‐documented shortcoming, BMI z ‐scores are still widely used to evaluate the response of obesity treatment in children with severe obesity . The BMI expressed as a percentage of a particular BMI cut‐off has been proposed as a more appropriate outcome parameter than BMI z ‐score in children with obesity.…”

Section: Introductionmentioning

confidence: 99%

Monitoring children and adolescents with severe obesity: body mass index (BMI), BMI z‐score or percentage above the International Obesity Task Force overweight cut‐off?

et al. 2019

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Aim: Body mass index (BMI) metrics are widely used as a proxy for adiposity in children with severe obesity. The BMI expressed as the percentage of a cut-off percentile for overweight or obesity has been proposed as a better alternative than BMI z-scores when monitoring children and adolescents with severe obesity.Methods: Annual changes in BMI, BMI z-score and the percentage above the International Obesity Task Force overweight cut-off (%IOTF-25) were compared with dual-energy X-ray absorptiometry (DXA) derived body fat (%BF-DXA) in 59 children and adolescents with severe obesity.Results: The change in %BF-DXA was correlated with the change in %IOTF-25 (r = 0.68) and BMI (r = 0.70), and somewhat less with the BMI z-score (r = 0.57). Cohen's Kappa statistic to detect an increase or decrease in %BF-DXA was fair for %IOTF-25 (j = 0.25; p = 0.04) and BMI (j = 0.33; p = 0.01), but not for the BMI z-score (j = 0.08; p = 0.5). The change in BMI was positively biased due to a natural increase with age. Conclusion: Changes in the BMI metrics included in the study are associated differentlyAbbreviations %BF, Percentage body fat; %IOTF-25, Percentage above the International Obesity Task Force definition of overweight; BMI, Body mass index; DXA, Dual-energy X-ray absorptiometry. Key notesThe percentage above the International Obesity Task Force overweight cut-off (%IOTF-25) has been suggested as an unbiased alternative with respect to age for the body mass index (BMI) or BMI z-score in children and adolescents with severe obesity. Changes in BMI, BMI z-scores and %IOTF-25 were compared with dual-energy x-ray absorptiometry of body composition. The %IOTF-25 might be a better alternative to BMI z-scores to monitor changes in adiposity.

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Effectiveness of a Hospital-Based Multidisciplinary Pediatric Weight Management Program: Two-Year Outcomes of PHIT Kids

Abstract: Children maintained treatment gains achieved during a 24-week family-based behavioral weight management program at 2-year follow-up. Although these findings suggest that gains are sustainable, further research is needed to understand how these long-term changes impact child health.

Cited by 31 publications

References 25 publications

The Limitations of Transforming Very High Body Mass Indexes into z -Scores among 8.7 Million 2- to 4-Year-Old Children

The Limitations of Transforming Very High Body Mass Indexes into z -Scores among 8.7 Million 2- to 4-Year-Old Children

Longitudinal changes in BMIz-scores among 45 414 2–4-year olds with severe obesity

Monitoring children and adolescents with severe obesity: body mass index (BMI), BMI z‐score or percentage above the International Obesity Task Force overweight cut‐off?

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