Strength of Association Between Body Mass Index and Physical Function Scores in Pediatric Burn Patients: A National Institute on Disability, Independent Living, and Rehabilitation Research Burn Model System Study

Abstract

Objective:

Increased body weight has been associated with reduced muscle wasting in the early catabolic phase after a severe burn. Yet, overweight and obese non-burn children often exhibit impaired musculoskeletal function, which may lead to poor physical function (PF). We aimed to determine the association between body mass index (BMI) at discharge and self-reported PF and caregiver proxy-reported PF during recovery of severely burned children.

Materials and methods:

This is a retrospective multisite longitudinal study in pediatric burn patients (8–17 y old at time of burn). PF outcome measures were self-reported mobility, proxy-reported mobility, and upper extremity PF evaluated using PROMIS measures at 6-, 12-, and 24-months post-injury. Primary exposure variable was BMI-for-age at discharge.

Results:

A total of 118 pediatric patients, aged 11.7 ± 3.3 y, with burns covering 37.6 ± 18.8 % of their total body surface area (TBSA) and BMI-for-age of 23.1 ± 5.4 kg.m⁻² at discharge were analyzed. BMI at discharge was not significantly associated with self-reported mobility scores 6 months after a burn (beta coefficient =−0.23, p=0.31), had a positive effect on mobility at 12 months (beta = 0.46, p=0.05), and no effect at 24 months post-injury (beta=−0.10, p=0.60), when adjusted for burn size. BMI did not have a significant effect on proxy-reported mobility or upper extremity PF.

Conclusion:

A greater BMI at discharge was associated with improved self-reported PF at 12 months after burn but not at 6 months or 24 months, which suggests a faster recovery of PF in pediatric patients of larger body weight. Our data suggests that a larger body weight does not compromise the recovery of PF after a burn.

1. INTRODUCTION

Burns are the fifth most common cause of unintentional non-fatal injury and one of the leading causes of physical disability among children [1]. The metabolic abnormalities in response to severe burns along with prolonged immobilization and bed rest are associated with muscle wasting [2, 3], with detrimental effects on physical function (PF) [4, 5]. With improved survival rates among severely burned patients cared for in high-income settings [6], focus has been shifted to the long-term recovery of individuals living with burns, where restoration of PF is an essential component. Functional recovery from burns and reintegration is a complex and long process that in severe cases can extend to years beyond acute burn care, directly impacting self-care and daily life [4, 5, 7]. In a cross-sectional study of 98 severely burn adult patients surveyed and physically examined, limited range of motion and difficulty in mobility, self-care, hand function and activities persisted for an average of 17 years after burn [5]. Rehabilitating the burn patient requires a multidisciplinary approach [3] that could be challenging for the obese pediatric patient. Overweight and obese children are typically less mobile and active, displaying a compromised musculoskeletal function [8, 9], with deficits in cardiorespiratory fitness relative to body mass, and skilled motor performance [10], compared with their normal-weight counterparts.

It is uncertain how obesity influences functional outcomes in the rehabilitative state following severe burns. Current knowledge pertaining to the obese burn patient is mostly limited to chance of survival and incidence of clinical complications in the critical and acute care settings [11]. Retrospective studies have shown either no effect of obesity [12, 13] or higher rates of specific complications in the obese burn patient but a potential edge of mild obesity on survival [12, 14, 15]. Body weight has been implicated in influencing skeletal muscle protein turnover post-burn among pediatric patients, where an increase in weight was associated with reduced muscle wasting in the early acute phase [2]. Preserving and/or restoring muscle mass and function is imperative for maintaining functional capacity in daily living after discharge, where the reported association between weight and skeletal muscle wasting might favor a higher BMI. Yet, the functional limitation and impaired mobility that is often seen in overweight and obese children [8, 10] may compromise the long-term recovery of burned pediatric patients and may lead to poor PF outcomes, directly impacting daily living.

Therefore, we aimed to determine the association between BMI at discharge and self-reported/proxy-reported PF in severely burned children in later phases of recovery, analyzing data collected as part of the BMS National Longitudinal Database. We opted for weight at discharge due to weight at admission being confounded by the fluid resuscitation process that can majorly inflate weight and produce inaccurate weight records. A recent study showed that burn patients with >20% TBSA burn had a median increase in weight above baseline of up to 8%, likely due to resuscitation fluids within the first week of hospitalization [16]. We hypothesized that a higher BMI at discharge would adversely affect longer-term self-reported and proxy-reported PF scores in severely burned children after hospital discharge.

2. METHODS

2.1. Study population and the Burn Model System National Longitudinal Database

The study population included burn pediatric patients (5–17 y old) enrolled in the BMS National Longitudinal Database, which is a multisite effort funded by the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR) from 1994 forward and collecting data from discharge from acute care and onwards, reviewed elsewhere [17] Supplement). We limited eligibility to patients that had PF outcome data collected at ≥1 follow-up timepoints and body weight and height collected at discharge. Amputation(s) may lead to underestimation of BMI; therefore, it was considered reasonable to exclude patients having undergone an amputation. BMS self-/proxy-reported PF outcomes, introduced in 2015, are assessed in patients ≥8 y (self-report) and ≥5 y (proxy-report) and at follow-up timepoints after discharge but not at discharge. Therefore, patients deceased before discharge were eliminated from the analysis (Figure 1). Ethical approval was obtained by the institutional review board of each BMS center, according to each center’s approved procedures [17]. All participants and their parents/guardians provided informed consent to participate.

Figure 1.

Flow chart of the study cohort.

2.2. Outcome measures: PROMIS self-reported PF /proxy-reported PF

Self-reported and proxy-reported PF were assessed by using outcome measures from PROMIS at 6, 12, and 24 mos and every 5y after burn in 5–17 y old patients. PROMIS is an NIH-funded initiative that developed over 300 self/proxy-reported measures of physical, mental, and social health [18]. We focused on the item banks that define self-reported mobility (4 items; PROMIS-25 Physical Function Mobility), and proxy-reported mobility (8 items; PROMIS Physical Function Mobility,) and upper extremity PF (8 items; PROMIS Physical Function Upper Extremity). PROMIS developed instruments for pediatric self-report in ages 8–17y and for proxy reporters for children aged 5–17y. As proxy responder served the mother/stepmother, father/stepfather, or guardian/other. The self-reported PF item bank consists of questions that are elements of the proxy-reported mobility item bank. Each item is rated on a scale from 0 (with no trouble) to 4 (not able to do) representing the past 7 days. The sum of raw scores is converted to standardized T-scores centered on the general US population with a mean of 50 and SD of 10, where higher scores indicate better PF [19]. Items on the forms are reverse coded to align with the direction of the instrument after T-score conversion.

2.3. Primary exposure variables: BMI (continuous), obesity status (categorical)

Height and weight at admission and discharge were obtained from medical records, and via patient self-report or proxy-report at follow-up. BMI was computed as weight by height squared (kg/m²) at discharge, unless otherwise stated. In children and adolescents, BMI depends on age and sex, and is referred to as BMI-for-age [20, 21]. Therefore, we utilized an age- and sex-corrected BMI corresponding to the BMI expected of an 18-year-old patient of the same BMI percentile as the patient in question. Details on the methodology used are given in the Supplement. Based on the estimated CDC Growth Charts percentiles and recommended cut-off values [20, 21], a binary variable classifying our pediatric population into overweight/obese (≥85^th percentile) and normal-weight (including underweights due to their low number, <85^th percentile) was created.

2.4. Covariates: Patient demographics and injury measures

Patient demographics were obtained through patient self-report and/or proxy survey completed at discharge. Age at discharge was calculated from date of discharge, with birth year accessed through medical chart abstraction. Given the deidentified nature of the data, it was not possible to determine the exact birth date, thus age at discharge and follow-up were calculated from the midpoint of birth year. Injury characteristics, including TBSA burned (%) and burn-related amputation (yes/no), and length of hospital stay (d), were collected from medical records at discharge.

2.5. Statistical analyses

Descriptive statistics for continuous variables are presented as group mean ± SD and median (IQR), and for categorical variables as frequencies and proportions. Bivariate analysis included correlation testing. To assess the relationship between BMI or overweight/obesity status and PF scores over time, we used mixed linear models for repeated measures and separate regression models per timepoint, adjusting for patient and injury characteristics (see online Supplement). For the associations between overweight/obesity status and PF scores, patients were classified into two groups based on BMI percentiles: overweight plus obese or normal plus under-weight (reference group). Sensitivity analyses were performed to test whether including underweight patients in the reference group is confounding the regression estimates. Analyses were conducted in SAS Studio (SAS University Edition, SAS Institute Inc., NC, USA). Two-sided statistical significance was considered for alpha at the 0.05 level.

3. RESULTS

From a total of 2828 pediatric patients included in the BMS National Longitudinal Database, 118 patients made it to our final dataset as detailed in the provided flow chart (Figure 1). As outlined in the flow chart (Figure 1), PF was not measured: in patients younger than <5 y old (n=1052), prior to the year 2015 (n=1044), and in patients deceased before discharge (n=505). After introduction of PROMIS item banks in 2015, PF records are missing in 89 participating patients. Height or weight records are missing in 2 patients. In one patient, BMI record entries were deemed implausible, such as a BMI change from 66–69 kg/m² while receiving acute care to 18 kg/m² at 6 mos after burn, and thus was excluded from further analysis. Seventeen patients had sustained amputation(s) and were excluded from the analysis as the extent of the amputation could not be inferred by the provided data and thus its effect on body weight was unable to be accounted for.

In the final sample of 118 pediatric patients (89 M, 29 F), PF scores were evaluated in up to 78 patients at 6 mos, up to 62 patients at 12 mos and up to 73 patients at 24 mos after burn (exact rates per self-report or proxy PF are shown in Table 1). The 118 pediatric patients aged on average 11.7 ± 3.3 y, with mean BMI-for-age at discharge being 23.1 ± 5.4 kg/m². Burns covered on average 37.6 ± 18.8 % of TBSA. PROMIS PF scores significantly improved over time in the recovery phase after burn (time effect, p<0.05). Self-reported mobility was significantly higher than proxy-reported mobility (p<0.05). Table 1 provides a summary of the main characteristics of the final population.

Table 1.

Patient demographics and injury characteristics at 6, 12, and 24 mos after burn.

Variable	6 mos		12 mos		24 mos
	Mean ± SD / [n]	Median (IQR)	Mean ± SD / [n]	Median (IQR)	Mean ± SD / [n]	Median (IQR)
Sample size per follow-up (n)	[78]		[62]		[73]
Age at discharge (y)	12.6 ± 3.1	12.6 (5.6)	11.7 ± 3.1	11.8 (5.5)	10.7 ± 2.9***	10.1 (4.9)
Sex (M/F)	[57/21]		[47/15]		[56/17]
Weight at discharge (kg)	46.9 ± 18.5	43.5 (25.0)	45.1 ± 19.5	43.0 (31.0)	38.8 ± 17.7**	35.0 (22.0)
Height at discharge (cm)	153.0 ± 17.0	155 (29.0)	149.1 ± 19.6	153.0 (32.0)	142.1 ± 19.5***	139.0 (34.0)
BMI at discharge (kg/m2)	19.4 ± 4.9	18.6 (4.9)	19.4 ± 4.6	18.8 (5.7)	18.3 ± 4.3	17.2 (5.0)
BMI-for-age at discharge (kg/m2)	23.1 ± 5.6	22.3 (6.4)	23.8 ± 5.6	22.8 (5.8)	23.2 ± 5.1	22.4 (5.8)
BMI percentiles at discharge	52.2 ± 34.1	55.6 (69.3)	57.3 ± 33.3	61.0 (54.7)	52.9 ± 34.1	56.8 (63.0)
Weight status at discharge
Obese (%)	9%		15%		12%
Overweight (%)	15%		16%		14%
Healthy weight (%)	65%		61%		60%
Underweight (%)	10%		8%		14%
TBSA burned (%)	36.2 ± 18.8	34.5 (29.0)	37.3 ± 19.1	34.5 (21.0)	39.0 ± 18.7	38.0 (22.0)
Length of stay in acute care (d)	33.4 ± 31.5	26.0 (19.0)	34.3 ± 36.2	26.0 (21.0)	33.6 ± 31.0	28.0 (19.0)
PROMIS physical function scores
Self-reported mobilitya	47.5 ± 10.9	49.0 (16.0)	48.8 ± 10.5	57.0 (16.0)	51.7 ± 8.6*	57.0 (9.5)
Proxy-reported mobilityb	45.7 ± 11.3	48.0 (19.0)	47.1 ± 10.8	52.0 (14.0)	49.9 ± 9.3***	56.0 (13.0)
Proxy-reported upper extremityc	44.3 ± 12.4	55.0 (21.0)	49.1 ± 10.6 *	55.0 (10.0)	51.0 ± 8.5*	55.0 (0.0)

BMI, body mass index; M/F, male female; PROMIS, patient-reported outcomes measurement information system; TBSA, total body surface area.

^*P<0.05,

^**P<0.01,

^***P<0.0001: compared to 6 mos; Tukey’s multiple comparison test.

^aSample size by timepoint/column: n=73; n=56; n=68.

^bSample size by timepoint/column: n=77; n=62; n=70.

^cSample size by timepoint/column: n=77; n=60; n=70.

3.1. Bivariate analysis between different PF scores

Self-reported PF was correlated with proxy-reported mobility scores (6 mos: r=0.85, p<0.001; 12 mos: r=0.67, p<0.001; 24mos: r=0.55, p<0.001) and with proxy-reported PF upper extremity (6 mos: r=0.58, p<0.001; 12 mos: r=0.21, NS; 24 mos: r=0.44, p<0.001). Proxy-reported PF upper extremity and mobility scores were also correlated (6 mos: r=0.55, p<0.001; 12 mos: r=0.49, p<0.001; 24 mos: r=0.46, p<0.001).

3.2. Regression model selection and final regression estimates

To select a parsimonious and interpretable model for accurate inference, we compared all possible regression models of the relationship between BMI-for-age at discharge, and PF scores (self-reported or proxy) at 6, 12, and 24 mos after burn, including TBSA, sex and age at discharge as covariates. Final regression estimates are presented in Table 2.

Table 2.

Regression estimates for the associations of BMI or overweight/obesity status at discharge and physical function (PF) scores at 6, 12, and 24 mos after burn, adjusted for TBSA burned.

Exposure variables per model	Self-reported mobility Estimate ± SE, p	Proxy mobility Estimate ± SE, p	Proxy upper extremity PF Estimate ± SE, p
6 mos follow up
BMI-for-age, TBSA	−0.23 ± 0.22, 0.31	−0.22 ± 0.23, 0.34	−0.22 ± 0.25, 0.37
Overweight/obese, TBSA	−4.24 ± 3.01, 0.16	−1.47 ± 2.95, 0.62	−2.91 ± 3.23, 0.37
12 mos follow up
BMI-for-age, TBSA	0.46 ± 0.23, 0.05	0.31 ± 0.22, 0.16	0.17 ± 0.23, 0.47
Overweight/obese, TBSA	4.44 ± 2.89, 0.13	2.16 ± 2.66, 0.42	4.23 ± 2.73, 0.13
24 mos follow up
BMI-for-age, TBSA	−0.10 ± 0.20, 0.60	0.12 ± 0.22, 0.57	−0.17 ± 0.19, 0.38
Overweight/obese, TBSA	−3.02 ± 2.37, 0.21	−0.03 ± 2.55, 0.99	−0.90 ± 2.26, 0.69

BMI, body mass index; mos, months; TBSA, total body surface area (burned).

3.3. BMI effect on self-reported mobility scores at 6, 12, 24 mos after burn

We performed mixed-effects model regression analysis to examine the effect of BMI-for-age at discharge on self-reported mobility scores measured at 6, 12 and 24 mos after burn. There was a significant BMI*time interaction effect (p=0.024), in a model adjusted also for TBSA burned, prompting us to examine the associations between BMI and mobility separately at 6, 12, and 24 mos. BMI-for-age at discharge did not exert a significant effect on self-reported mobility scores at 6 mos after burn (beta coefficient =−0.23, p=0.31), had a positive effect on mobility at 12 mos post injury (beta = 0.46, p=0.05; Supplemental Figure S1 and Supplement text), and no effect at 24 mos (beta=−0.10, p=0.60) adjusted for TBSA burned (Table 2). To investigate further the association between higher BMI at discharge and better self-reported mobility at 12 mos, we categorized the sample into overweight/obese and non-overweight/obese pediatric patients based on the BMI-for-age percentiles (Table 2). A binary classification approach was selected due to the small group sizes not permitting comparisons between four groups (Table 1). As with BMI-for-age, there was a significant interaction effect between overweight/obese versus normal/underweight patients over time, adjusted for TBSA burned, on self-reported PF (mixed-effects interaction effect, p=0.016). However, the overweight/obese group did not exert a significant effect on self-reported PF when tested at 6, 12, and 24 mos separately. Yet, we observed that 13 of 17 (76%) of the overweight/obese patients had maximal mobility scores, compared to 18 of 39 (46%) of non-overweight/non-obese patients with maximal mobility scores at 12 mos after a burn (data not shown). All patients that reached maximal mobility scores maintained the maximal scores at 24 mos post-injury. The regression estimates were robust to different reference groups (including versus excluding underweight patients).

3.4. BMI effect on proxy-reported mobility and upper extremity PF scores at 6, 12, 24 mos after burn

Mixed-effects models for mobility PF and upper extremity PF scores at 6, 12, and 24 mos regressed on BMI-for-age did not identify any significant main effects or interaction effects of BMI with time. The association between BMI-for-age and mobility PF score was not significant either at 6 mos (beta = −0.22, p=0.34), 12 mos (beta = 0.31, p=0.16), or 24 mos (beta=0.12, p=0.57), adjusted for TBSA burned. Proxy-reported upper extremity physical function was not significantly associated with BMI-for-age at 6 mos (beta = −0.22, p=0.37), 12 mos (beta=0.17, p=0.47), or 24 mos (beta=−0.17, p=0.38), adjusted for TBSA burned.

4. DISCUSSION

The present study set out to address the uncertainty regarding the effect of increased BMI on PF outcomes in the rehabilitative state following severe burns. Prior research has shown a reduction in mortality with increasing BMI, where the mildly obese (30–34.9 kg/m²) burn patients appear to show increased survival [14]. Yet, data in non-burn children consistently show compromised mobility and functional impairments in the overweight and obese [8–10]. We hypothesized that increasing BMI at the time of hospital discharge would compromise the long-term recovery of PF outcomes in burned pediatric patients. Contrary to our hypothesis, a greater BMI at discharge had no significant impact on self-reported PF of the lower extremities (mobility) at 6 or 24 mos after burn, and in fact was associated with improved self-reported mobility at 12 mos after burn, which suggests a faster recovery of PF in pediatric patients of larger body weight. For PF scores reported by proxies, BMI exerted no significant influence at 6, 12 or 24 mos after a burn. At the very least, our data suggests that a larger body weight at hospital discharge does not compromise the recovery of PF after a burn.

Poor PF after severe burns can persist for months to years beyond acute burn care [4, 5, 7]. In the present cohort of burned children, we examined how physical function over a span of 24 mos after injury is influenced by increasing BMI. Evidence from studies in non-burned children suggests that overweight and obese children experience musculoskeletal pain and discomfort among other orthopedic complications [8, 9, 22], compromised skilled motor performance, as well as deficits in muscle strength and cardiorespiratory fitness relative to body mass [10]. Hence, we hypothesized that a larger BMI would interact with the effects of burns on longer-term PF in an additive or synergistic manner. Yet, our results did not support this hypothesis, but rather showed that PF is largely unaffected by BMI at discharge and in fact, BMI possibly contributes to a faster functional recovery after a burn. Patients with greater body weight for their height and age (BMI-for-age) at discharge reported better mobility scores at 12 mos after burn while at 24 mos they scored similarly on PF irrespective of their BMI, indicating a speedier recovery.

Preserving and/or restoring muscle mass and function is crucial for the burn survivor to retain mobility and the capacity to return to a functional life after hospital discharge [3, 23]. In severely burned children, loss of leg lean body mass and diminished leg muscle strength and function was reported at 6 mos after burn [24]. Muscle strength measurements in severely burned adults remained depressed over an average of 38 mos after injury [25]. With regards to body weight, we have previously identified a significant association between increasing weight and reduced skeletal muscle protein breakdown in 100 pediatric ICU patients with burns covering >30% of TBSA [2]. Likewise, being overweight/obese before becoming critically ill was shown to blunt muscle wasting [26]. Given skeletal muscle’s role in PF, we speculate that reduced skeletal muscle wasting in pediatric burn patients with increasing weight may partly explain the faster PF recovery with increasing BMI we reported here or at a minimum cancel out any negative impact of extra weight on musculoskeletal health and functioning. Another alternative is that the excess body weight acts as a greater stimulus for muscle growth, which is widely accepted in non-burned adults [27]. On a different note, another explanation may be that children of larger BMI may perceive they function better in the recovery phase of a burn due to a potentially impaired PF prior to burns compared to children of lower BMI. In other words, they may reach their perceived maximal PF faster in the recovery period after a burn due to an already impaired PF prior to the burn, a phenomenon termed in the literature as “response shift” [28, 29].

Our analysis showed different patterns between self-reported mobility and mobility reported by the proxies. Self-report is considered the method of choice for measuring patient-reported outcomes in children, when possible, as prior evidence suggests [30, 31]. Yet, proxy-reported outcomes may be the only available option for children of very young age, who are illiterate, have cognitive difficulties, or are ill. Specific to the BMS study pediatric burn population and PROMIS PF domains, a recent BMS study identified significant disagreement between the self-reported and proxy-reported mobility scores in burn survivors aged 8 to 17 y, with proxies reporting lower PF scores than the patient by 2.5±8.7 units [32]. Likewise, our study cohort showed lower PF scores in the proxy reports compared to patient reports. The discrepancies between informants described in the literature might further explain the lack of an association between BMI and proxy-reported PF at 12 mos after injury. Still, both informant types offer valuable information through their own perception of the outcome which can drive decision-making related to seeking healthcare [33].

4.1. Study Limitations

A common challenge with survey instruments is how well they compare to widely accepted, well-validated measures. While clinical laboratory outcome measures offer an objective measure of physical function [34], patient-reported outcome measures reflect patient’s perceived level of functioning and changes in patient-reported outcomes reflect changes in perceived symptoms and function, which is an essential component in evaluating therapeutical interventions. The PROMIS initiative, a partnership between US academic institutions and the NIH, developed PROMIS item banks and their short forms [35]. Since development of the PROMIS instruments, they have been tested for their reliability, responsiveness, and validity against well-validated established measures in the general and various patient populations [35–38]. PROMIS domains of PF have been validated and their responsiveness tested in pediatric patients with chronic health conditions, including obesity, sickle cell disease, kidney disease, cancer, and rheumatic disease [39] and were recently validated in adult burn survivors [40]. Still, future research should opt to implement comprehensive assessments of PF, consisting of objective PF measures, such as the 6-min walking test [34, 41, 42], and patient-reported outcome measures to better direct clinical care and research therapeutic interventions. A further limitation of this study is the rather small sample size due to most of the original dataset not meeting the eligibility criteria, as outlined in the flow chart (Figure 1). A total of 109 patients aged 5–17 y old and alive at discharge had either missing PF outcome data, were amputated and therefore excluded, or had uncertain/not ascertained BMI entries. Yet, they were of a similar average age (excluded vs included: 11.3 y vs 11.7 y), BMI (excluded vs included: 19.6 kg/m² vs 18.9) and TBSA burned (excluded vs included: 40.3 vs 37.6 %) (data not shown). The low number of underweight (< 5^th percentile of CDC BMI-for-age chart) patients did not allow for that group of patients to be investigated separately but was merged to the normal-weight pediatric patients. Longer-term outcomes of burns have been less studied when compared to studies during acute burn care. Patient-reported outcomes on PF were introduced to the BMS National Longitudinal Database in 2015, which allowed us to analyze a 4-year span of the dataset for the purposes of this investigation. Our finding of faster recovery of self-reported PF in pediatric patients of larger body weights should be re-examined in larger sample sizes and ideally, to complement clinical objective measures of PF.

4.2. Conclusion

Pediatric burn patients exhibit improved self-reported mobility and proxy-reported mobility and upper extremities function over time after hospital discharge, with proxy-reports of mobility scoring lower than self-reports. A greater BMI at discharge had no significant impact on self-reported mobility at 6 mos or 24 mos after burn. However, a greater BMI was associated with improved mobility at 12 mos after burn, which suggests a faster recovery of PF for pediatric patients of larger body weight. Our analysis in pediatric burn patients indicates that a larger body weight at discharge, possibly reflecting greater muscle mass, does not compromise but has the capacity to expedite the recovery of PF after a burn. This further highlights the role of nutritional and pharmacological management of the hypermetabolic stress response to preserve muscle mass and body weight in the early catabolic phase after a burn.

Highlights.

• Burns are one of the leading causes of long-term physical disability among children.

• Rehabilitating the burn patient can be a lifelong process requiring a multidisciplinary approach, where restoration of physical function is an essential component.

• Increased body weight is linked to less muscle loss after a pediatric burn. Yet, excess body weight can lead to poor physical function in non-burned individuals.

• Our analysis suggests that excess body weight does not compromise recovery of physical function in pediatric patients with burns and may even expedite it.

Abbreviations:

BMI

body mass index

BMS

burn model system

CDC

Centers for Disease Control and Prevention

d

day(s)

M/F

male/female

mos

months

NIDILRR

National Institute on Disability, Independent Living, and Rehabilitation Research

PF

physical function

PROMIS

Patient-Reported Outcomes Measurement Information System

TBSA

total body surface area

y

year(s)