How does muscularity assessed by bedside methods compare to computed tomography muscle area at intensive care unit admission? A pilot prospective cross-sectional study.

BACKGROUND: Low muscularity and malnutrition at intensive care unit (ICU) admission have been associated with negative clinical outcomes. There are limited data available evaluating the validity of bedside techniques to measure muscle mass in critically ill adults. We aimed to compare bedside methods for muscle mass assessment [bioimpedance spectroscopy (BIS), arm anthropometry and subjective physical assessment] against reference technology [computed tomography (CT)] at ICU admission. METHODS: Adults who had CT scanning at the third lumbar area <72 h after ICU admission were prospectively recruited. Bedside methods were performed within 48 h of the CT scan. Pearson's correlation compared CT muscle area with BIS-derived fat-free mass (FFM) (kg) and FFM-Chamney (kg) (adjusted for overhydration), mid-upper arm circumference (cm) and mid-arm muscle circumference (cm). Depleted muscle stores were determined using published thresholds for each method. Cohen's kappa (κ) was used to evaluate the agreement between bedside and CT assessment of muscularity status (normal or low). RESULTS: Fifty participants were enrolled. There were strong correlations between CT muscle area and FFM values and mid-arm muscle circumference (P < 0.001). Using FFM-Chamney, all six (100%) participants with low CT muscle area were detected (κ = 0.723). FFM-BIS, arm anthropometry and subjective physical assessment methods detected 28%-38% of participants with low CT muscle area. CONCLUSIONS: BIS-derived FFM using an adjustment algorithm for overhydration was correlated with CT muscle area and had good agreement with muscularity status assessed by CT image analysis. Arm anthropometry and subjective physical assessment techniques were not able to reliably detect participants with low CT muscle area.

Body composition during growth in children: limitations and perspectives of bioelectrical impedance analysis.

There are a number of differences between the body composition of children and adults. Body composition measurements in children are inherently challenging, because of the rapid growth-related changes in height, weight, fat-free mass (FFM) and fat mass (FM), but they are fundamental for the quality of the clinical follow-up. All body composition measurements for clinical use are 'indirect' methods based on assumptions that do not hold true in all situations or subjects. The clinician must primarily rely on two-compartment models (that is, FM and FFM) for routine determination of body composition of children. Bioelectrical impedance analysis (BIA) is promising as a bedside method, because of its low cost and ease of use. This paper gives an overview of the differences in body composition between adults and children in order to understand and appreciate the difference in body composition during growth. It further discusses the use and limitations of BIA/bioelectrical spectroscopy (BIA/BIS) in children. Single-frequency and multi-frequency BIA equations must be refined to better reflect the body composition of children of specific ethnicities and ages but will require development and cross-validation. In conclusion, recent studies suggest that BIA-derived body composition and phase angle measurements are valuable to assess nutritional status and growth in children, and may be useful to determine baseline measurements at hospital admission, and to monitor progress of nutrition treatment or change in nutritional status during hospitalization.

Bioelectrical impedance analysis to estimate body composition in surgical and oncological patients: a systematic review.

OBJECTIVE: Bioelectrical impedance analysis (BIA) is a commonly used method for the evaluation of body composition. However, BIA estimations are subject to uncertainties.The aim of this systematic review was to explore the variability of empirical prediction equations used in BIA estimations and to evaluate the validity of BIA estimations in adult surgical and oncological patients. SUBJECTS: Studies developing new empirical prediction equations and studies evaluating the validity of BIA estimations compared with a reference method were included. Only studies using BIA devices measuring the entire body were included. Studies that included patients with altered body composition or a disturbed fluid balance and studies written in languages other than English were excluded.To illustrate variability between equations, fixed normal reference values of resistance values were entered into the existing empirical prediction equations of the included studies and the results were plotted in figures. The validity was expressed by the difference in means between BIA estimates and the reference method, and relative difference in %. RESULTS: Substantial variability between equations for groups (including men and women) was found for total body water (TBW) and fat free mass (FFM). The gender-specific existing general equations assume less variability for TBW and FFM. BIA mainly underestimated TBW (range relative difference -18.8% to +7.2%) and FFM (range relative differences -15.2% to +3.8%). Estimates of the fat mass (FM) demonstrated large variability (range relative difference -15.7 to +43.1%). CONCLUSIONS: Application of equations validated in healthy subjects to predict body composition performs less well in oncologic and surgical patients. We suggest that BIA estimations, irrespective of the device, can only be useful when performed longitudinally and under the same standard conditions.

Making the invisible visible: bioelectrical impedance analysis demonstrates unfavourable body composition in rheumatoid arthritis patients in clinical practice.

OBJECTIVES: To examine differences between the assessment of body composition by body mass index (BMI) and bioelectrical impedance analysis (BIA) in patients with rheumatoid arthritis (RA). METHOD: The body composition of RA patients was assessed during their visit to the outpatient department of a Dutch academic hospital using BMI, fat-free mass index (FFMI), and fat mass index (FMI). FFMI and FMI were determined by single-frequency BIA. RESULTS: Sixty-five consecutive RA patients (83% women, mean age 58 years, median disease duration 7 years) with moderately active disease [mean Disease Activity Score using 28 joint counts (DAS28) = 3.40; mean Rheumatoid Arthritis Disease Activity Index (RADAI) score = 3.49] and moderate disability [mean Health Assessment Questionnaire (HAQ) score = 0.87] were included. Based on BMI, 2% of our study population were underweight, 45% had a healthy body composition, and 54% were overweight or obese. Based on BIA, 18% of the patients showed a low FFMI and 74% had a high or very high FMI. Low FFMI was found in 44% of the women with a normal BMI, and high FMI was found in 40% of the women and 75% of the men with a normal BMI. CONCLUSIONS: A high frequency of unfavourable body composition, predominantly reduced FFMI and elevated FMI, was found in a cohort of RA patients with moderately active disease, turning BMI into an unreliable method for assessment of body composition in RA. BIA, however, might be the preferred method to assess FFMI and FMI in RA patients in clinical practice, as it is easy to use and relatively inexpensive.

Dietician-delivered intensive nutritional support is associated with a decrease in severe postoperative complications after surgery in patients with esophageal cancer.

The aim of this study was to evaluate the effect of dietician-delivered intensive nutritional support (INS) on postoperative outcome in patients with esophageal cancer. Approximately 50-80% of patients with esophageal cancer are malnourished at the time of diagnosis. Malnutrition enhances the risk of postoperative complications, resulting in delay of postoperative recovery and impairment of quality of life. Sixty-five patients with esophageal cancer were included. All patients who received surgery (n = 28) in the time frame between March 2009 and April 2010, the first year after the start of INS, were included in the INS intervention group. The control group (n = 37) consisted of patients who received surgery during the 3 years before the start of INS. Logistic regression analysis was used to compare differences in severity of postoperative complications using the Dindo classification. Linear regression was applied to evaluate differences in preoperative weight change. The adjusted odds ratio for developing serious complications after surgery of INS compared with the control group was 0.23 (95% confidence interval: 0.053-0.97; P = 0.045). Benefit was mainly observed in patients who received neoadjuvant therapy before esophagectomy (n = 35). The INS program furthermore resulted in a relative preoperative weight gain in comparison with the control group of +4.8% (P = 0.009, adjusted) in these neoadjuvant-treated patients. This study shows that dietician-delivered INS preserves preoperative weight and decreases severe postoperative complications in patients with esophageal cancer.

The link between obesity and low circulating 25-hydroxyvitamin D concentrations: considerations and implications.

Obesity and vitamin D deficiency have both been recognized as major public health issues worldwide, and there is growing evidence that they are related, although the cause-effect relationship remains unclear. Could obesity be contributing to low circulating 25-hydroxyvitamin D concentrations? Alternatively, could low vitamin D status predispose to obesity? In this review, the relationship between low circulating 25-hydroxyvitamin D and obesity, and possible underlying reasons from both perspectives, is presented. One potential mechanism by which obesity could contribute to low serum 25-hydroxyvitamin D is adipose sequestration of vitamin D. On the other hand, adipose tissue has both the vitamin D receptor and the ability to synthesize 1,25-dihydroxyvitamin D, and there is evidence that vitamin D may regulate adipose tissue mass, differentiation and metabolism in ways that might contribute to obesity. Of particular interest, vitamin D deficiency is common both before and after bariatric surgery, and is often difficult to treat, particularly with the more malabsorptive procedures. Additional research is needed to elucidate the complex and multifaceted factors underlying the association between low circulating 25-hydroxyvitamin D and obesity, and to identify optimal treatment approaches in obese individuals and in bariatric surgical patients both before and after surgery.

A comparison of bioimpedance methods for detection of body cell mass change in HIV infection.

The maintenance of body cell mass (BCM) is critical for survival in human immunodeficiency virus (HIV) infection. Accuracy of bioimpedance for measuring change (Delta) in intracellular water (ICW), which defines BCM, is uncertain. To evaluate bioimpedance-estimated DeltaBCM, the ICW of 21 weight-losing HIV patients was measured before and after anabolic steroid therapy by dilution (total body water by deuterium - extracellular water by bromide) and bioimpedance. Multiple-frequency modeling- and dilution-determined DeltaICW did not differ. The DeltaICW was predicted poorly by 50-kHz parallel reactance, 50-kHz impedance, and 200 - 5-kHz impedance. The DeltaICW predicted by 500 - 5-kHz impedance was closer to, but statistically different from, dilution-determined DeltaICW. However, the effect of random error on the measurement of systematic error in the 500 - 5-kHz method was 12-13% of the average measured DeltaICW; this was nearly twice the percent difference between obtained and threshold statistics. Although the 500 - 5-kHz method cannot be fully rejected, these results support the conclusion that only the multiple-frequency modeling approach accurately monitors DeltaBCM in HIV infection.