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Calipers vs bia: The debate continues: Author's reply
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TO TH BTIDR
Schoeller (3), who reported that BIA can predict total body water, not weight. SHARONHIMMELSTEIN, MNS, RD University of New Mexico, Albuquerque References 1. Khaled MA, Mc(utcheon MJ, Reddy S, Pearman PL, Hunter GR, Weinsier RL. Electrical impedance in assessing human body composition: the BIA method. Am J Clin Nutr. 1988;47: 789-792. 2. Bohm D, Odaishi M,Beyerlein C, Overbeck W.Total body water: changes during dialysis estimated by bioimpedance analysis. Infusionstherapie. 1990:17 (3): 75-78. 3. Kushner RF, Schoeller DA. Estimation of total body water by bioelectrical impedance analysis. Am J Clin Vutr. 1986;44: 417-424. Author's Reply: We appreciate Himmelstein's comments about caliper validity, but maintain that, despite careful attention, considerable intraindividual and interindividual variation produce different results between examinations and examiners. Because caliper methods have been used and validated mostly in healthy, young adults, we wanted to see whether BIA, a relatively simple, convenient, and noninvasive technique could be used in the nutrition assessment of dialysis populations in clinical settings. We agree that BIA and caliper methods should be compared with a better criterion to validate accuracy at estimating percentage of fat. But deuterium dilution is not appropriate for estimatingpercent body fat (1) and is more effective at estimating total body water (TBW). Bohm et al (2) demonstrated BIA's validity in estimating percent of TBWin dialysis patients. Though hydrostatic weighing is more accurate for evaluating percent body fat, it is invasive and difficult to do in dialysis patients. Lukaski et al (3) showed that, in healthy adults, BIA has a lower rate of predictive error in estimating fat than anthropometric measurements when hydrodensitometry is the standard. Studies should compare BIA with computed tomography or magnetic resonance imaging. We did not state that "the poor correlation between methods was attributable to inaccuracies in the caliper method that result from alterations in fluid status and vascular access." We simply stated that some problems might be attributable to fluid status and vascular access. We did not look at the site or type of vascular access in our dialysis patients. Moore et al (4) have shown different results in triceps skinfolds (TSF) and arm muscle circumference values of dialysis patients between vascular and nonvascular arms. Difficulties in obtaining accurate TSF measurements because of peripheral edema might
affect the results. Benich et al (5) were unable to obtain anthropometric measurements on 26% of their intensive care unit patients because of generalized edema. Himmelstein suggests that fluid status changes are likely to affect BIA measurements to a greater extent than the caliper method because BIA estimates TBW. The study referenced states that BIA is useful in determining percent body fat in human beings if body fluids are not perturbed several hours before the measurements. However, Runge et al (6) showed no statistical difference in percentage of fat estimated by BIA or hydrostatic weighing with exercise-induced dehydration. The error from Kushner and Schoeller's study occurred because the abbreviation %TBW was incorrectly expanded to total body weight rather than total body water and was not corrected on the galley proof. MEENAKSHI RAMMOHAN, MS, RD Northwestern University Medical School, Chicago, Ill References 1. Jensen MD Research techniques for body composition assessment. J Am Diet Assoc. 1992; 92: 454-460 2. Bohm D,Odaishi M,Beyerlein C, Overbeck W.Total body water: changes during dialysis estimated by bioimpedance analysis. Infusionstherapie. 1990;17 (3): 75-78 3. LukaskiHC, BolonchukWW, HallCB, Siders WA. Validation of tetrapolar bioelectrical impedance method to assess human body composition. JAppl Physiol. 1986;60: 1327-1332. 4. Moore C, Bodnar D, Kovach M, Magnuson M, Paganini E. Effect of vascular access and intradialytic fluid change on triceps skinfold and arm muscle circumference. Counc Renal Nutr Q. 1982;4: 13-14. 5. Benich RD, Twyman DC, Fierke A. The failure of anthropometry as a nutritional assessment. Henry FordHosp Med J 1986; 34: 95-99. 6. Runge PJ, Eisenman PA, Johnson SC. Effects of exercise induced dehydration on bioelectrical impedance analyzation to determine bodycomposition.Med Sci SportsExerc. 1987;19 (2): S38.
EW RIE FOR RIDSk: DUBES CASE MINAC To the Editors: In response to Insull's commentary (Insull WJr. Dietitians as intervention specialists: a continuing challenge for the 1990s. JAm DietAssoc. 1992;92: 551-552), I've developed a multidisciplinary team approach with the RD in the prominent role of case manager. This approach helps ensure comprehensive medical care while sending a consistent nutrition message to patients and to health care providers of the importance of diet therapy.
Diabetes Assessment Flow Sheet Diabetes Initial Nutrition Visit Date: S: Referral/Presenting Complaint: Present Diet: Medications: Concurrent Medical Problems: Signs/symptoms: Socioeconomic factors: Family/peer support: Occupation/activity level: Prior diabetes teaching: Home testing: O: Height: Weight: Ideal body weight (IBW): %IBW: Significant laboratory values: Clinical: A: P: Patient/provider goals:
Diabetes Database Glucose (fasting): HbA,: Creatinine: Protein/urine: Blood pressure:
Glucose (random): Cholesterol: Blood ureanitrogen: Weight: Medications list:
Referrals Eye: Foot:
Nutrition:
Glucose Monitoring Date: Reading: Information to include on the diabetes assessmentflow sheet and diabetesflouw chart. In primary-care clinics, patients with diabetes are referred to an RD, who documents the initial session on a standardized nutrition assessment form. Placing a flow sheet for documenting laboratory values and referrals to other providers on the back of the nutrition assessment form creates an easily accessible database for comprehensive care. (See Figure above.) The case manager is responsible for reminding patients and providers of necessary referrals and appointments. The flow sheet helps identify developing trends in laboratory values. Often the diagnosis of non-insulin-dependent diabetes mellitus is accompanied by other diagnoses - eg, hypertension, obesity, or cardiovascular disease - in which diet assessment and counseling are important parts of the treatment. Close monitoring reduces medical costs by helping patients make necessary life-style changes and dietary modifications and improving treatment response. Using the proposed flow sheet with the standardized nutrition assessment is away for RDs to assume responsibilities of intervention specialist for the medical care team. As case managers, RDs can be more active in interdisciplinary efforts to improve patients' access to nutrition services. CAROLE S. MACKEY, MS, RD Neuw York, NY
JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION / 401
TO TH BTIDR
Schoeller (3), who reported that BIA can predict total body water, not weight. SHARONHIMMELSTEIN, MNS, RD University of New Mexico, Albuquerque References 1. Khaled MA, Mc(utcheon MJ, Reddy S, Pearman PL, Hunter GR, Weinsier RL. Electrical impedance in assessing human body composition: the BIA method. Am J Clin Nutr. 1988;47: 789-792. 2. Bohm D, Odaishi M,Beyerlein C, Overbeck W.Total body water: changes during dialysis estimated by bioimpedance analysis. Infusionstherapie. 1990:17 (3): 75-78. 3. Kushner RF, Schoeller DA. Estimation of total body water by bioelectrical impedance analysis. Am J Clin Vutr. 1986;44: 417-424. Author's Reply: We appreciate Himmelstein's comments about caliper validity, but maintain that, despite careful attention, considerable intraindividual and interindividual variation produce different results between examinations and examiners. Because caliper methods have been used and validated mostly in healthy, young adults, we wanted to see whether BIA, a relatively simple, convenient, and noninvasive technique could be used in the nutrition assessment of dialysis populations in clinical settings. We agree that BIA and caliper methods should be compared with a better criterion to validate accuracy at estimating percentage of fat. But deuterium dilution is not appropriate for estimatingpercent body fat (1) and is more effective at estimating total body water (TBW). Bohm et al (2) demonstrated BIA's validity in estimating percent of TBWin dialysis patients. Though hydrostatic weighing is more accurate for evaluating percent body fat, it is invasive and difficult to do in dialysis patients. Lukaski et al (3) showed that, in healthy adults, BIA has a lower rate of predictive error in estimating fat than anthropometric measurements when hydrodensitometry is the standard. Studies should compare BIA with computed tomography or magnetic resonance imaging. We did not state that "the poor correlation between methods was attributable to inaccuracies in the caliper method that result from alterations in fluid status and vascular access." We simply stated that some problems might be attributable to fluid status and vascular access. We did not look at the site or type of vascular access in our dialysis patients. Moore et al (4) have shown different results in triceps skinfolds (TSF) and arm muscle circumference values of dialysis patients between vascular and nonvascular arms. Difficulties in obtaining accurate TSF measurements because of peripheral edema might
affect the results. Benich et al (5) were unable to obtain anthropometric measurements on 26% of their intensive care unit patients because of generalized edema. Himmelstein suggests that fluid status changes are likely to affect BIA measurements to a greater extent than the caliper method because BIA estimates TBW. The study referenced states that BIA is useful in determining percent body fat in human beings if body fluids are not perturbed several hours before the measurements. However, Runge et al (6) showed no statistical difference in percentage of fat estimated by BIA or hydrostatic weighing with exercise-induced dehydration. The error from Kushner and Schoeller's study occurred because the abbreviation %TBW was incorrectly expanded to total body weight rather than total body water and was not corrected on the galley proof. MEENAKSHI RAMMOHAN, MS, RD Northwestern University Medical School, Chicago, Ill References 1. Jensen MD Research techniques for body composition assessment. J Am Diet Assoc. 1992; 92: 454-460 2. Bohm D,Odaishi M,Beyerlein C, Overbeck W.Total body water: changes during dialysis estimated by bioimpedance analysis. Infusionstherapie. 1990;17 (3): 75-78 3. LukaskiHC, BolonchukWW, HallCB, Siders WA. Validation of tetrapolar bioelectrical impedance method to assess human body composition. JAppl Physiol. 1986;60: 1327-1332. 4. Moore C, Bodnar D, Kovach M, Magnuson M, Paganini E. Effect of vascular access and intradialytic fluid change on triceps skinfold and arm muscle circumference. Counc Renal Nutr Q. 1982;4: 13-14. 5. Benich RD, Twyman DC, Fierke A. The failure of anthropometry as a nutritional assessment. Henry FordHosp Med J 1986; 34: 95-99. 6. Runge PJ, Eisenman PA, Johnson SC. Effects of exercise induced dehydration on bioelectrical impedance analyzation to determine bodycomposition.Med Sci SportsExerc. 1987;19 (2): S38.
EW RIE FOR RIDSk: DUBES CASE MINAC To the Editors: In response to Insull's commentary (Insull WJr. Dietitians as intervention specialists: a continuing challenge for the 1990s. JAm DietAssoc. 1992;92: 551-552), I've developed a multidisciplinary team approach with the RD in the prominent role of case manager. This approach helps ensure comprehensive medical care while sending a consistent nutrition message to patients and to health care providers of the importance of diet therapy.
Diabetes Assessment Flow Sheet Diabetes Initial Nutrition Visit Date: S: Referral/Presenting Complaint: Present Diet: Medications: Concurrent Medical Problems: Signs/symptoms: Socioeconomic factors: Family/peer support: Occupation/activity level: Prior diabetes teaching: Home testing: O: Height: Weight: Ideal body weight (IBW): %IBW: Significant laboratory values: Clinical: A: P: Patient/provider goals:
Diabetes Database Glucose (fasting): HbA,: Creatinine: Protein/urine: Blood pressure:
Glucose (random): Cholesterol: Blood ureanitrogen: Weight: Medications list:
Referrals Eye: Foot:
Nutrition:
Glucose Monitoring Date: Reading: Information to include on the diabetes assessmentflow sheet and diabetesflouw chart. In primary-care clinics, patients with diabetes are referred to an RD, who documents the initial session on a standardized nutrition assessment form. Placing a flow sheet for documenting laboratory values and referrals to other providers on the back of the nutrition assessment form creates an easily accessible database for comprehensive care. (See Figure above.) The case manager is responsible for reminding patients and providers of necessary referrals and appointments. The flow sheet helps identify developing trends in laboratory values. Often the diagnosis of non-insulin-dependent diabetes mellitus is accompanied by other diagnoses - eg, hypertension, obesity, or cardiovascular disease - in which diet assessment and counseling are important parts of the treatment. Close monitoring reduces medical costs by helping patients make necessary life-style changes and dietary modifications and improving treatment response. Using the proposed flow sheet with the standardized nutrition assessment is away for RDs to assume responsibilities of intervention specialist for the medical care team. As case managers, RDs can be more active in interdisciplinary efforts to improve patients' access to nutrition services. CAROLE S. MACKEY, MS, RD Neuw York, NY
JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION / 401