ESPEN GUIDELINESBioelectrical impedance analysis—part II: utilization in clinical practice
Section snippets
Background
Nearly 1600 papers about BIA are found in English medical literature between 1990 and 2003, with 450 being published in the last 3 years. This vast body of literature makes it difficult to understand when and how BIA should be used. Part I of these ESPEN 2-part guidelines on BIA discussed the principles, methods and BIA equations.1
Part II of these guidelines, limited to adults, reviews the current applications and limitations and presents the ESPEN recommendations for BIA in clinical practice
BIA measurement conditions
The factors/conditions that affect BIA are shown in Table 1. Subjects must be measured (recall values are not acceptable) for height and weight at the time of the BIA measurement. Standardized conditions with regard to body position, previous exercise, dietary intake and skin temperature must be respected.2, 3, 4 Consumption of food and beverage may decrease impedance by 4–15 Ω over a 2–4 h period after meals, representing an error smaller than 3%.2, 4 Measurements on two consecutive days at the
Healthy subjects, ethnic groups and body shape abnormalities
It is essential that appropriate BIA equations are chosen for the population studies. Published equations and criteria of selection are presented in part 1. Longitudinal changes in FFM and BF can be assessed with BIA, but are controversial when significant weight loss occurs because of physiological changes.8, 9, 10, 11, 12, 13 Assessment of changes in FFM, BF or TBW of less than 1.5–2 kg is limited, because of limitations in BIA precision.14 Reproducibility over a 7-week period was excellent in
Conditions in specific groups with an emphasis on those at risk for malnutrition and weight loss
Table 2 shows that variable and contradictory results are obtained by BIA for FFM, BF and BCM in various pathologies15, 16, 17, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33 by a number of different BIA equations22, 27, 29, 30, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49 with comments or evaluation shown in the last two column of the table. These discrepancies stem not only from the BIA method limitations but also from limitations in reference methods (see part I).1
Conditions of overweight and obesity
The studies69, 70, 71, 72, 73, 74 that have evaluated BIA in overweight and obese subjects are shown in Table 5, with comments or evaluation shown in the last column of the table. Currently, it appears that BIA equations can estimate body composition in overweight patients. BIA has been shown to be valid with BMIs to 34 kg/m2.24, 43 In morbid obesity, most predictive equations are unable to predict static body composition and are not reproducible for individuals over time.69 The disproportion
Conditions with a potential for altered hydration
Table 6 shows various studies81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118 in subjects with altered hydration, which determine TBW, ECW and BCM based on a number of body composition models or equations,22, 35, 38, 40, 45, 119, 120, 121, 122, 123, 124, 125 with comments or evaluation shown in the last two columns of the table. These discrepancies stem not only from the BIA
Conclusion
BIA is non-invasive, relatively inexpensive, does not expose to ionizing radiation, has very limited between observer variations and can be performed in almost any subject because it is portable. BIA works well in healthy subjects and chronic diseases with a validated BIA equation that is appropriate with regard to age, sex and race. However, clinical use of BIA in subjects at extremes of BMI ranges and in subjects with abnormal hydration cannot be recommended for routine assessment of patients
Acknowledgements
The support by Public Foundation Nutrition 2000Plus for Ursula G. Kyle is acknowledged.
References (126)
- et al.
Bioelectrical impedance analysis—part I
Review of principles and methods. Clin Nutr
(2004) - et al.
Clinical characteristics influencing bioelectrical impedance analysis measurements
Am J Clin Nutr
(1996) - et al.
Within-day variation of bioelectrical resistance measurements in patients with chronic obstructive pulmonary disease
Clin Nutr
(1990) - et al.
Changes in fat-free mass during weight loss measured by biolectrical impedance and by densitometry
Am J Clin Nutr
(1989) - et al.
Validity of bioelectrical–impedance analysis in measuring changes in lean body mass during weight reduction
Am J Clin Nutr
(1991) Do bioimpedance changes reflect weight, not composition?
Am J Clin Nutr
(1991)- et al.
Is bioimpedance a good predictor of body-composition change
Am J Clin Nutr
(1992) - et al.
Comparison of measurements of body composition by total body potassium, bioimpedance analysis, and dual energy X-ray absorptiometry in hypopituitary adults before and during growth hormone treatment
Am J Clin Nutr
(1995) - et al.
Measurement of body fat by dual-energy X-ray absorptiometry and bioimpedance analysis in men with prostate cancer
Nutrition
(2002) - et al.
Prediction of body cell mass, fat-free mass, and total body water with bioelectrical impedance analysiseffects of race, sex, and disease
Am J Clin Nutr
(1996)