Validation of estimates of total body water in pediatric dialysis patients by deuterium dilution

BACKGROUND: Current K-DOQI recommendations call for an assessment of dialysis adequacy that depends critically on an estimate of total body water (TBW). Such estimates are problematic in children since the range of patient size is large, and often formulas derived in normals are not validated in end-stage renal disease. Gold standard methods of TBW measurement, such as deuterium dilution ((2)H(2)O), are not appropriate in the clinical setting, yet noninvasive methods such as bioimpedance analysis (BIA) and dual energy x-ray absorptiometry (DEXA) have not been independently validated. METHODS: We studied 14 stable pediatric dialysis patients on 1 to 3 occasions using (2)H(2)O dilution, BIA, DEXA, and anthropometry to measure TBW. We compared our data set to previously published formulae for TBW to determine root mean square error (RMSE) and skew of the estimate. RESULTS: TBW prediction based upon the anthropometric formula proposed by the Pediatric Peritoneal Dialysis Consortium provided the best fit to our independent data set with RMSE = 2.15 L, and no skew by Bland-Altman analysis. Other formulas produced large, clinically relevant errors; obese subjects confounded many estimates. TBW calculated from hydrated lean body mass from DEXA scan was reliable with RMSE = 1.03 L and no skew. BIA-derived estimates can be useful, although the magnitude of RMSE ranged from 1.45 to 6.24 L, and one formula produced skewed results. CONCLUSION: Techniques for estimating TBW in pediatric dialysis patients must be validated by independent data sets before being incorporated into clinical and research practice.     

Limitations in anthropometric calculations of total body water in patients on peritoneal dialysis

Having an accurate estimation of total body water (TBW) is essential for the evaluation of dialysis efficacy in peritoneal dialysis (PD) patients. In this study, TBW volumes were measured by tritium dilution (TBW(THO)) in 165 PD patients and compared with TBW calculations according to the Watson formulas. An alternative anthropometric formula based on the present PD population was also developed and validated in an independent sample of 29 PD patients. Furthermore, the relation between TBW(THO) and body surface area (BSA) according to the formula of Gehan was analyzed. Body composition was assessed by a four-compartment model, based on measurements of TBW(THO) and total body potassium. Mean values of TBW by the Watson formulas were almost identical to TBW(THO), and the correlation coefficient for the relationship of calculated to measured volumes was 0.89 (P = 0.001). However, both anthropometric formulas-the Watson formulas as well as the new, alternative one-overestimated TBW in obese patients and vice versa in lean patients. Similarly, TBW was underestimated in patients who were overhydrated. The correlation coefficient between TBW(THO) and BSA was 0.708 for males and 0.797 for females (P = 0.0001 for both). In obese patients, the relationship was even closer (r = 0.924 and 0.911, respectively). In conclusion, anthropometric formulas to calculate TBW showed a considerable intraindividual variability compared with measured values. This was related to body composition features, such as degree of obesity and hydration. In contrast, BSA correlated closely to TBW in obese individuals. TBW as estimated by anthropometric formulas must be analyzed with caution, especially in the very obese or very lean patient.     

Volume status and body composition of chronic dialysis patients: utility of bioelectric impedance plethysmography

We assessed the utility of bioelectric impedance plethysmography (BIA) for measuring acute volume changes and body composition in patients with renal disease. Chronic hemodialysis and peritoneal dialysis patients were evaluated before and after dialysis. Total body water, as measured by BIA, predicts body weight. Acute changes in body water, induced by dialysis, are not predicted well by data derived from BIA. Body fat (%) and fat-free mass (%), determined by anthropometry, are predicted well by body composition data derived by BIA. BIA is useful for assessing body composition in this population, but must be cautiously applied to the measurement of acute volume changes.     

Assessment of body composition in children with chronic renal failure

In children with chronic renal failure treated conservatively by dialysis or by transplantation, various alterations of the nutritional, metabolic and fluid homeostasis may occur that may critically affect the patients’ acute and chronic well-being. In the past, the assessment of body composition in children was hampered by insufficient precision, standardization and/or availability of appropriate anthropometric tools. Recently, there have been several methodological advances that may facilitate close and precise monitoring of body composition in this population. Specifically, the use of body mass index (BMI) data in children has become possible by the introduction of pediatric reference values processed for the calculation of standard deviation scores accounting for the skewed distribution of BMI. Skewness-adapted reference data have also been provided for percentage fat mass as assessed by multisite skinfold measurements. In addition, bioelectrical impedance analysis has been validated in healthy children as well as in pediatric dialysis and renal transplant populations. This novel auxological technique provides a highly reproducible, non-invasive and inexpensive way of assessing changes in total body water content in dialysed patients, as well as changes in fat and fat-free mass prior to dialysis and after renal transplantation. Received: 6 August 1999 / Revised: 16 December 1999 / Accepted: 23 December 1999     

Anthropometric and body composition assessment in dialysis patients

Anthropometric and body composition assessments provide important information about the nutritional status of dialysis patients. Anthropometric measurements describe body size, fatness, and leanness in dialysis patients and have been collected in the Modification of Diet in Renal Disease (MDRD) and HEMO studies. Dialysis patients present special problems for anthropometry, including decreased functional status and increased comorbidity, that challenge nutrition assessment methodology. Recumbent anthropometric techniques are recommended and stature is estimated from knee height. Measures of weight, stature, calf circumference, arm circumference, and triceps and subscapular skinfolds have recently been reported for dialysis patients, who tend to be shorter, lighter, and have less adipose tissue than healthy persons of the same age. The HEMO study anthropometric data provide a clinical reference for assessing the nutritional status of dialysis patients. The most common body composition methods used with dialysis patients are dual energy X-ray absorptiometry (DEXA), bioelectrical impedance, total body water (TBW), and prediction equations, but they are not recommended for assessment of predialysis patients, as estimates are best obtained postdialysis. The TBW volume used in calculating the dose of dialysis has commonly been predicted from the limited, out-of-date equations of Watson, based on nonrepresentative samples. New prediction equations are available for white, black, and Mexican American children and adults. Watson's data are not representative of the TBW of U.S. men and women. The greater TBW in non-Hispanic black men and women and Mexican American women reflects the greater levels of obesity in the U.S. population.     

Whole body and regional body composition in patients with chronic renal failure

BACKGROUND.: Nutritional state is a powerful prognostic factor in chronicrenal failure (CRF). Techniques for the assessment of nutritionhave limitations which are often most marked in the presenceof renal disease. We have used techniques of body compositionanalysis to assess the nutritional state of groups of patientswith CRF. METHODS.: Body composition was measured in groups of patients with advancedCRF on conservative treatment, peritoneal dialysis, and haemodialysisand the results compared with a healthy control group. The selectioncriteria for the CRF patients ensured that they were ‘stable’with no recent intercurrent illness, and dialysis adequacy wassatisfactory according to currently accepted targets. RESULTS.: Whole body dual energy X-ray absorptiometry (DEXA) found significantreduction in lean tissue in haemodialysis patients and femaleperitoneal dialysis patients. Regional analysis with DEXA showedreduction in limb (especially arm), lean tissue in CRF patients,with arm lean tissue being reduced in all three CRF groups forfemales and both dialysis groups for males. Limb/trunk leantissue ratios were significantly reduced for all CRF groups.Bioelectrical impedance showed reductions of fat-free mass inthe same groups who had reduced whole body lean tissue withDEXA, but skinfold anthropometry failed to detect any significantreduction in fat-free mass. CONCLUSIONS.: We conclude that even in ‘healthy’ groups of CRFpatients receiving adequate dialytic and dietary management,lean tissue depletion is a common problem. Regional analysisby DEXA, with measurement of limb lean tissue mass is a moresensitive method for the detection of lean tissue depletionthan measurement of whole body lean tissue in patients withCRF.     

Anthropometrically estimated total body water volumes are larger than modeled urea volume in chronic hemodialysis patients: effects of age,race, and gender

BACKGROUND: The modeled volume of urea distribution (Vm) in intermittently hemodialyzed patients is often compared with total body water (TBW) volume predicted from population studies of patient anthropometrics (Vant). METHODS: Using data from the HEMO Study, we compared Vm determined by both blood-side and dialysate-side urea kinetic models with Vant as calculated by the Watson, Hume-Weyers, and Chertow anthropometric equations. RESULTS: Median levels of dialysate-based Vm and blood-based Vm agreed (43% and 44% of body weight, respectively). These volumes were lower than anthropometric estimates of TBW, which had median values of 52% to 55% of body weight for the three formulas evaluated. The difference between the Watson equation for TBW and modeled urea volume was greater in Caucasians (19%) than in African Americans (13%). Correlations between Vm and Vant determined by each of the three anthropometric estimation equations were similar; but Vant derived from the Watson formula had a slightly higher correlation with Vm. The difference between Vm and the anthropometric formulas was greatest with the Chertow equation, less with the Hume-Weyers formula, and least with the Watson estimate. The age term in the Watson equation for men that adjusts Vant downward with increasing age reduced an age effect on the difference between Vant and Vm in men. CONCLUSION: The findings show that kinetically derived values for V from blood-side and dialysate-side modeling are similar, and that these modeled urea volumes are lower by a substantial amount than anthropometric estimates of TBW. The higher values for anthropometry-derived TBW in hemodialyzed patients could be due to measurement errors. However, the possibility exists that TBW space is contracted in patients with end-stage renal disease (ESRD) or that the TBW space and the urea distribution space are not identical.     

Association analysis of body composition with survival among prevalent peritoneal dialysis patients

International Urology and Nephrology - Progressive decline in lean mass and gain of fat mass are common in patients treated with peritoneal dialysis (PD). It is unclear whether body composition or...     

Androgen receptor CAG repeats and body composition among Ariaal men

To determine the population variation in the androgen receptor (AR) and its association with body composition in a subsistence population, we sampled 87 settled and 65 nomadic males ages 20+ among the Ariaal of northern Kenya. Anthropometric measures included height, body mass index, fat-free mass (FFM), upper arm muscle plus bone area (AMPBA), % body fat (%BF), suprailliac skinfold (SISF), and waist-to-hip ratio. Salivary testosterone (T) was determined from both morning (Am T) and afternoon (Pm T) samples. Hair roots were obtained for genotyping AR CAG repeat length. AR CAG repeat length did not vary between the two sub-groups (overall value = 22.6 ± 3.1). Multiple regression models, controlling for age and residence, indicate that Pm T was positively associated with all measures of body composition. AR CAG repeat length was a significant positive predictor of height, FFM, %BF, SISF and waist circumference. There was a significant negative Pm T by AR CAG repeat length interaction in predicting all anthropometric measures but AMPBA. These findings provide evidence for population variation in AR CAG repeat length and suggest that both T and AR CAG length play a role in body composition in this extremely lean population.     

Body composition assessment and methodology in nonathletic and athletic adolescent and adult males and females

The purpose of this review is to outline methodology for assessing body composition utilizing anthropometric and densitometric techniques. The objective of body composition assessment is to measure body fat and lean body mass. The quantity of these components varies due to growth, physical activity, dietary regimens, and aging. Anthropometric techniques incorporate selected skinfolds, circumferences, skeletal widths, or other variables to estimate body composition within k2.0-4.0%. These techniques are adequate for field testing of groups or individuals, but are population specific. Densitometry measures body volume irrespective of physique, sex, or age. This laboratory technique estimates body composition within 1.0-2.0%, is more difficult to administer, but is not population specific. Some limitation exists with any present technique due to biological variability and incomplete research of reference body composition in children, females, and the aged. J Orthop Sports Phys Ther 1984;5(6):336-347.     

Associations between plasma ghrelin levels and body composition in end-stage renal disease: a longitudinal study.

BACKGROUND: Ghrelin is a newly detected orexigenic gastric hormone that stimulates food intake. Increased levels of ghrelin are often found in disease states associated with wasting. Wasting is a common phenomenon in end-stage renal disease (ESRD) patients in whom elevated ghrelin levels have been reported. However, no data are available on the relationship between body composition and plasma ghrelin levels in this patient group. METHODS: The study population consisted of 108 (71 males) ESRD patients aged 53+/-12 years. Body composition, nutritional status (subjective global assessment), estimated protein intake (nPNA), plasma ghrelin, plasma insulin and serum leptin were evaluated close to the start of dialysis treatment. Twelve healthy subjects (nine males, 44+/-6 years) served as the control group. A longitudinal evaluation of changes in plasma ghrelin and body composition was performed in 52 of the patients after 12 months of dialysis treatment. RESULTS: Markedly elevated plasma ghrelin levels (843+/-485 vs 443+/-302 pg/ml; P<0.01) were observed in ESRD patients compared with controls. Basal plasma ghrelin levels correlated significantly with plasma insulin (R = -0.32; P<0.05), body mass index (R = -0.24; P<0.05), log serum leptin levels (R = -0.23; P<0.05) and truncal fat mass (R = -0.25; P<0.05). The longitudinal analysis of body composition demonstrated that whereas fat mass increased (23.7+/-8.6 to 25.3+/-9.9 kg; P<0.05) and plasma ghrelin levels decreased (855+/-429 to 693+/-408 pg/ml; P<0.05) significantly in peritoneal dialysis patients, no significant changes in either body composition or plasma ghrelin levels were found in patients treated by haemodialysis. CONCLUSION: Markedly elevated plasma ghrelin levels are found in advanced renal failure and correlate with fat mass, plasma insulin and serum leptin levels. Changes in plasma ghrelin during 12 months of peritoneal dialysis treatment are associated with changes in body composition.     

Body Composition Analysis of Patients on Waiting List for Cadaveric Renal Transplantation: A Comparison of Hemodialysis and Peritoneal Dialysis Patients

BackgroundBioelectrical impedance analysis is a simple, noninvasive method of assessing body composition. Dialysis modality and selection of buffer type may have an impact on body composition. The aim of our study was to compare body compositions of patients from the waiting list for cadaveric renal transplantation according to the dialysis modality.MethodsWe examined a total of 152 (110 hemodialysis [HD] and 42 continuous ambulatory peritoneal dialysis [CAPD]) patients. Demographic data were collected from patient charts. The last 6 months routine laboratory evaluations including hemoglobin, serum creatinine, intact parathyroid hormone, albumin, C reactive protein, calcium, phosphorus were collected. Body compositions were measured using the Tanita BC-420MA Body Composition Analyzer (Tanita, Tokyo, Japan). We made a subanalysis of the CAPD group according to buffer choices as follows: lactate-buffered (n = 16) and bicarbonate/lactate–buffered (n = 26) solution users.ResultsThe body weight (P = .022), body mass index (BMI; 25.8 ± 4.7 vs 23.4 ± 4.9 kg/m², P = .009), muscle mass (P = .01), fat-free mass (P = .013), and visceral fat ratio (9.5 ± 5.4 vs 7.3 ± 4.1 %, P = .022) were significantly higher in the CAPD group. Total body water of CAPD patients were also higher (P = .003), but total body water ratios of HD and CAPD groups were similar. Fat and fat-free mass ratios of patient groups were also similar. Comparing CAPD subgroups we observed that patients using bicarbonate/lactate–buffered solutions had higher body weights (P = .038), BMI (27.1 ± 5 vs 23.7 ± 3.5 kg/m², P = .018) values, and visceral fat ratios (8.0 ± 5.2 vs 4.6 ± 2.5 %, P = .023). These patients also tend to have higher fat mass without statistical significance (P = .074). Fat, muscle, and fat-free mass total body water ratios of peritoneal dialysis subgroups were similar.ConclusionWe believe that body composition analysis should be used as a complementary method for assessing nutritional status of PD and CAPD patients as body weight or BMI measurements do not reflect fat, muscle masses, and visceral fat ratios in these patients. Stable, well nourished CAPD patients should be closely observed and be encouraged to increase daily exercise and/or decrease calorie intake from other sources to decrease risks associated with abdominal obesity.     

Total body water reference values and prediction equations for adults

BACKGROUND: The clinical interpretation of total body water (TBW) necessitates the availability of timely comparative reference data. The prediction of TBW volume in renal disease is critical in order to prescribe and monitor the dose of dialysis in the determination of Kt/V. In clinical practice, urea distribution (V) is commonly predicted from anthropometric equations that are several decades old and for white patients only. This article presents new reference values and prediction equations for TBW from anthropometry for white and black adults. METHODS: The study sample included four data sets, two from Ohio and one each from New Mexico and New York, for a total of 604 white men, 128 black men, 772 white women, and 191 black women who were 18 to 90 years of age. The TBW concentration was measured by the deuterium or tritium oxide dilution method, and body composition was measured with a Lunar DXA machine. An all-possible-subsets of regression was used to predict TBW. The accuracy of the selected equations was confirmed by cross-validation. RESULTS: Blacks had larger TBW means than whites at all age groups. The 75th TBW percentile for whites approximated the TBW median for blacks at most ages. The white men and black men and women had the largest TBW means ever reported for healthy individuals. The race- and sex-specific TBW prediction equations included age, weight, and stature, with body mass index (BMI) substituted for weight in the white men. The root mean square errors (RMSEs) and standard errors for the individual (SEIs) ranged from approximately 3.8 to 5.0 L for the men and from 3.3 to 3.6 L for the women. In both men and women, high values of TBW were associated with high levels of total body fat (TBF) and fat-free mass (FFM). CONCLUSION:: TBW in these healthy adults is relatively stable through a large portion of adulthood. There are significant race and sex differences in TBW. These accurate and precise equations for TBW provide a useful tool for the clinical prediction of TBW in renal disease for white and black adults. These are the first TBW prediction equations that are specific for blacks.     

Body composition measurements using bioimpedance analysis in peritoneal dialysis patients are affected by the presence of dialysate

The presence of peritoneal dialysate when performing bioimpedance analysis may affect body composition measurements. The aim of this study was to evaluate the impact of dialysate on body composition measurements in Asians. Forty‐one patients undergoing maintenance peritoneal dialysis in our hospital peritoneal dialysis unit were included in this study. Dialysate was drained from the abdomen prior to measurement, and bioimpedance analysis was performed using multi‐frequency bioimpedance analysis, with each subject in a standing position (D‐). Dialysate was then administered and the measurement was repeated (D+). The presence of peritoneal dialysate led to an increase in intracellular water (ICW), extracellular water (ECW), and total body water (D‐: 20.33 ± 3.72 L for ICW and 13.53 ± 2.54 L for ECW; D+: 20.96 ± 3.78 L for ICW and 14.10 ± 2.59 L for ECW; P < 0.001 for both variables). Total and trunk oedema indices were higher in the presence of peritoneal dialysate. In addition, the presence of peritoneal dialysate led to an overestimation of mineral content and free fat mass (FFM) for the total body; but led to an underestimation of body fat (D‐: 45.80 ± 8.26 kg for FFM and 19.30 ± 6.27 kg for body fat; D+: 47.51 ± 8.38 kg for FFM and 17.59 ± 6.47 kg for body fat; P < 0.001 for both variables). Our results demonstrate that the presence of peritoneal dialysate leads to an overestimation of FFM and an underestimation of fat mass. An empty abdomen is recommended when evaluating body composition using bioimpedance analysis.     

Assessment of body composition by dual energy X-ray absorptiometry, skinfold thickness and creatinine kinetics in chronic kidney disease patients.

BACKGROUND: Finding a method that can be routinely used to assess body composition with minimum error is still a challenge for those who work with chronic kidney disease (CKD) patients. This study aimed to compare the value of two surrogate techniques, skinfold thickness (SKF) and creatinine kinetics (CK) with dual energy X-ray absorptiometry (DEXA) as the reference method for measuring body fat and fat-free mass in non-dialysed CKD patients. METHODS: The body fat and fat-free mass of 50 non-dialysed CKD patients (38 male, 12 female) were measured by DEXA and compared with measurements obtained by SKF and CK. RESULTS: The mean values of body fat and fat-free mass obtained by SKF and CK differed significantly from measurements made by DEXA. The intra-class correlation coefficient (r) for body fat between SKF and DEXA (r = 0.74) and between CK and DEXA (r = 0.47) indicated a moderate degree of reproducibility. A Bland and Altman plot analysis showed a better agreement between SKF and DEXA [5.8 +/- 3.9% (-2.0 to 13.6)] than between CK and DEXA [8.8 +/- 8.8% (-8.8 to 26.4)]. Regarding fat-free mass, the intra-class correlation coefficient (r) between SKF and DEXA (r = 0.85) indicated a good degree of reproducibility, while that between SKF and CK (r = 0.57) indicated a moderate degree of reproducibility. The Bland and Altman plot analysis for fat-free mass showed that DEXA agreed better with SKF [-3.1 +/- 3.4 kg (-9.9 to 3.7)] than with CK [-5.5 +/- 6.4 kg (-18.2 to 7.3)]. CONCLUSION: Skinfold thickness seems to be the method of choice for evaluating body fat. The limitations inherent to DEXA in evaluating fat-free mass makes it difficult to designate an alternate method of choice for assessing this body compartment.     

Estimating total body water in children on the basis of height and weight: a reevaluation of the formulas of Mellits and Cheek

An estimate of total body water (TBW) has important implications in clinical practice. For patients on peritoneal dialysis (PD), the estimate is critical when determining the delivered dialysis dose. The formulas of Mellits and Cheek have been recommended to estimate TBW in children on PD. These formulas were derived from healthy children, and very few infants were included. To assess the accuracy of these formulas, the original data were obtained and additional data from a broad literature review were compiled. The majority of the new data points were in the infant age range. Data were fitted using least-squares methodology and backward elimination to obtain a parsimonious model. Best fits were obtained using age, gender, and weight or a height x weight term. The results of the curves are as follows: Infants 0 to 3 mo (n= 71): TBW = 0.887 x (Wt)(0.83) Children 3 mo to 13 yr(n = 167): TBW = 0.0846 x 0.95([if female]) x (Ht xWt)(0.65) Children > 13 yr (n = 99): TBW = 0.0758 x 0.84([if female]) x (Ht x Wt)(0.69) When compared with the previous Mellits and Cheek formulas, the new formula fits better for infants (comparison of prediction errors, P < 0.0004). These newer formulas do not perform significantly better for the older two groups. Actual TBW measurement in children on PD must still be determined to verify the use of these formulas and to accurately assess dialysis delivery and adequacy.     

Impact of dialysis modality on body composition in patients with end-stage renal disease.

Loss of muscle mass and altered body fat distribution (i.e. increased central fat stores in the presence of normal peripheral fat stores) have been reported in patients on hemodialysis (HD), when compared to normal volunteers. Whether treatment of end-stage renal disease (ESRD) with continuous ambulatory peritoneal dialysis (CAPD) would alter body composition in a different manner than HD is unknown. To answer this question, two groups (n = 11 each) of male patients with ESRD (matched for age, residual renal function, body weight and body height as well as physical activity) were studied. Muscle mass and body fat distribution were assessed using computed tomography. Mid-thigh muscle area, peripheral and central fat stores were similar between the two groups of dialysis patients. In both patient groups muscle mass and fat stores were independent of duration of dialysis, age, daily protein intake and residual renal function. In CAPD-patients mid-thigh muscle area was correlated with plasma albumin (r = 0.56, p < 0.05), while serum cholesterol level was correlated with mediastinal fat area (r = 0.81, p < 0.01). The present results indicate that both treatment modalities of ESRD (HD vs CAPD) result in similar changes of body composition. Despite continuous glucose loading in CAPD-patients, neither central nor peripheral fat stores are increased in these subjects compared with HD treated patients.     

The effect of arteriovenous fistulae in haemodialysis patients on whole body and segmental bioelectrical impedance

BACKGROUND: Bioelectrical impedance (BIA) is a potentially useful method for measuring body water and soft-tissue composition in patients with chronic renal failure. The majority of whole body impedance is derived from the limbs with only a small contribution from the trunk, and thus abnormalities of the limbs could have an exaggerated effect on estimates of total body impedance. METHODS: This study investigated the effect of arteriovenous fistulae in the arm in haemodialysis patients on body composition measurement by whole body BIA. Body composition estimates from measurements on fistula and non-fistula sides of the body were compared and segmental impedance measurements of the arms were also performed. RESULTS: Whole body resistance was markedly lower on the fistula side of the body compared with the nonfistula side at 517.1 (124.3) omega compared with 561.5 (121.2) omega, P < 0.0005. This difference was accounted for by differences in the arm segments. This was attributed to swelling of the fistula arm which had a greater mid- arm circumference at 28.5 (2.1) cm compared with the contralateral side at 27.5 (2.0) cm, P < 0.05. This resulted in greater estimates for total body water from the fistula side at 38.6 (10.0) kg compared with 36.6 (8.6) kg from the non-fistula side, P < 0.05 and fat-free mass at 51.1 (11.8) kg from the fistula side compared with 49.1 (11.2) kg from the non-fistula side, P < 0.005. Estimates of body fat from the fistula side, 13.1 (6.9) kg, were less than the nonfistula side, 15.0 (6.0), P < 0.005. CONCLUSIONS: The presence of arteriovenous fistulae for vascular access in haemodialysis patients may have a significant effect on estimates of body composition by BIA.      

双能源X线吸收法及生物电阻抗法测定营养不良病人机体组分

目的 :应用双能源X线吸收测定法及生物电阻抗测定法 ,检测营养不良病人的机体组成改变。方法 :中等程度以上营养不良住院病人 6 8例 ,其中男 40例 ,女 2 8例 ,中位年龄 5 3岁 (37～ 6 8岁 )作为研究对象。 78例健康志愿者 (男 44例 ,女 34例 )为对照者 ,中位年龄 5 2岁 (38～ 6 2岁 )。分别应用HologicQDR - 2 0 0 0双能源X线测定仪及HYDRAECF/ICF42 0 0多频率生物电阻抗测定仪测定机体组成。结果 :营养不良病人实际平均体重是理想体重的 6 8.8%,其体质指数、三头肌皮褶厚度、上臂肌围、白蛋白、转铁蛋白、前白蛋白及淋巴细胞总数均明显低于正常值 ,属中、重度营养不良范围。营养不良病人的体脂、瘦组织群、细胞总体及细胞内水含量均明显低于健康志愿者 (P