Measurement of body composition in burned children: is there a gold standard?

BACKGROUND: Maintaining lean body mass (LBM) after a severe burn is an essential goal of modern burn treatment. An accurate determination of LBM is necessary for short- and long-term therapeutic decisions. The aim of this study was to compare 2 measurement methods for body composition, whole-body potassium counting (K count) and dual x-ray absorptiometry (DEXA), in a large prospective clinical trial in severely burned pediatric patients. METHODS: Two-hundred seventy-nine patients admitted with burns covering 40% of total body surface area (TBSA) were enrolled in the study. Patients enrolled were controls or received long-term treatment with recombinant human growth hormone (rhGH). Near-simultaneous measurements of LBM with DEXA and fat-free mass (FFM) with K count were performed at hospital discharge and at 6, 9, 12, 18, and 24 months post injury. Results were correlated using Pearson's regression analysis. Agreement between the 2 methods was analyzed with the Bland-Altman method. RESULTS: Age, gender distribution, weight, burn size, and admission time from injury were not significantly different between control and treatment groups. rhGH and control patients at all time points postburn showed a good correlation between LBM and FFM measurements (R(2) between 0.9 and 0.95). Bland-Altman revealed that the mean bias and 95% limits of agreement depended only on patient weight and not on treatment or time postburn. The 95% limits ranged from 0.1 +/- 2.9 kg for LBM or FFM in 7- to 18-kg patients to 16.3 +/- 17.8 kg for LBM or FFM in patients >60 kg. CONCLUSIONS: DEXA can provide a sufficiently accurate determination of LBM and changes in body composition, but a correction factor must be included for older children and adolescents with more LBM. DEXA scans are easier, cheaper, and less stressful for the patient, and this method should be used rather than the K count.

Comparison of self-reported and monitored compliance of daily injection of human growth hormone in burned children.

Objectives. We compared insulin-like growth factor (IGF-I) levels obtained in two groups with different methods of assessing compliance. Burned children were randomized to receive a daily injection of 0.05-0.1mg/kg per day of recombinant human growth hormone (rhGH) or placebo. Study design. One hundred twenty-five children (age range 6 months to 17 years) with total body surface area burns >40% participated in the study. Baseline levels of IGF-I were obtained at hospital discharge, at which time daily injections of rhGH or placebo were initiated. Assessment of IGF-I levels was repeated at 3-month intervals for 1 year. A directly monitored group met daily with research staff that witnessed the preparation and injection of the study drug. A self-reported group completed a Self Reported Compliance Questionnaire (SRCQ) that assessed compliance with drug regimen. A compliance of at least 85% (injections reported administered/maximal total injections possible) was accepted as being compliant. Data were analyzed using a one-way ANOVA followed by a Student Newman-Kuels test, with the results given as means+/-S.E.M. Results. The percent change in IGF-I levels between 6 and 9 months in the self-reported (22.7+/-7.9%) and monitored groups (21.9+/-8.6%) were similar. In contrast, the percent change in IGF-I levels in the placebo group was significantly decreased (-5.6+/-6.3%). Conclusions. Self-reported scores via an SRCQ is a potentially useful and valid method of assessing compliance of rhGH injections, as both reported and directly monitored methods yield similar changes in levels of IGF-I.

IGF-I/IGFBP-3 equilibrates ratios of pro- to anti-inflammatory cytokines, which are predictors for organ function in severely burned pediatric patients.

BACKGROUND: We hypothesized that ratios of pro- to anti-inflammatory cytokines can be associated with hepatic, cardiac, and renal function after a severe trauma and can be used as predictors for clinical outcome. Furthermore, insulin-like growth factor-I (IGF-I) in combination with its principle binding protein (IGFBP-3) equilibrates pro- to anti-inflammatory cytokine ratios and improves homeostasis of severely burned pediatric patients. MATERIALS AND METHODS: Seventeen severely burned children were given a continuous infusion of IGF-I/BP-3 for 5 days after wound excision and grafting; seven were given saline during the same time period to serve as controls. Patient demographics and mortality were determined. Five days after excision and grafting, cardiac function was determined and blood samples were taken for serum levels of IGF-I, IGFBP-3, creatinine, pre-albumin, cholinesterase, pro-inflammatory cytokines (IL-1beta, IL-6, and TNF), and anti-inflammatory cytokines (IL-2, IL-4, IL-10 and IFN-gamma). RESULTS: There were no differences between IGF-I/BP-3 and controls in age, gender, burn size, or mortality. Serum IGF-I in burned children given the IGF-I/BP-3 complex increased from 102 + 15 to 433 + 33 microg/ml and IGFBP-3 increased from 1.5 + 0.2 to 3.0 + 0.2 microg/ml (p < 0.05). Serum pre-albumin and cholinesterase increased with IGF-I/BP-3, whereas serum creatinine decreased when compared to controls (p < 0.05). IGF-I/BP-3 increased cardiac index by 16% and stroke volume index by 15% (p < 0.05). These improvements in organ homeostasis were associated with decreased ratios of pro- to anti-inflammatory cytokines in the IGF-I/BP-3 group when compared to controls (p < 0.05). CONCLUSIONS: Increased ratios of pro- to anti-inflammatory cytokines may indicate a higher risk for the incidence of multi-organ failure. We therefore suggest that ratios of pro-inflammatory to anti-inflammatory cytokines can be used to predict organ function. We further conclude that IGF-I/BP-3 equilibrates the balance between pro- and anti-inflammatory cytokines, which was associated with improved cardiac, renal, and hepatic function. The benefit of IGF-I/BP-3 in ameliorating the inflammatory response may also apply in reducing the multi-organ failure often observed in the state of severe trauma.