EAL

EE: Harris-Benedict: Obese and Nonobese (2005)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

1) to compare predicted and measured REE in moderately obese women

2) to determine the composition of the subjects’ excess weight

3) to ascertain whether differences between predicted and measured REE were related to differences in body composition between obese and nonobese controls

Inclusion Criteria:

1. Understand and give written consent

2. Moderately obese.

Exclusion Criteria:

1. Refusal to consent

2. Not meeting inclusion criteria

3. Diseases in subjects that were excluded: thyroid, heart, cerebrovascular and kidney disease, pregnancy, type I diabetes mellitus, cancer

4. Medications excluded: any medications known to influence metabolic rate

Description of Study Protocol:

Study Protocol:

Compare the measured REE with predicted REE. REE was predicted using three formula:

1) the Harris-Benedict equation, based on ht, wt, age, and sex

2) the tables of Boothby, based on body surface area

3) the equation of Kleiber, based on estimated metabolic body size.

“Steady state”- 5 consecutive data pointes having a coefficient of variation of <= 5%

ANTHROPOMETRIC:

Body composition was assessed by 3 methods: anthropometry, total body potassium and total body water

Body composition values were compared with age- and sex-matched nonobese controls

Ht measured ? yes

Wt measured ? yes

Fat-free mass measured? yes

Body surface area, BMI

CLINICAL:

Monitored heart rate? Not addressed

Body temperature? Not addressed

Medications administered? Not addressed

Resting energy expenditure:

IC type: MMC Horizon System

Equipment of Calibration: not addressed

Coefficient of variation using std gases: Not addressed

Rest before measure (state length of time rested if available): not addressed

Measurement length: not specified

Steady state: Continuous measurements until steady state was achieved; 5 consecutive data pointes having a coefficient of variation of <= 5%

Fasting length: 6 h; : Early morning and early afternoon

Exercise restrictions XX hr prior to test? not addressed

Room temp: not addressed

No. of measures within the measurement period: Continuous measures

Were some measures eliminated? Yes, non-equilibrated measurements were eliminated.

Were a set of measurements averaged? yes; continuous measurements were computed at one-minute interval

Coefficient of variation in subjects measures? yes

Training of measurer? no

Subject training of measuring process? no

DIETARY

Not a controlled factor

Intervening factor:

Did not address physical activity levels, smoking status, or substances use.

Statistical tests:

Paired student t test

Pearson product moment correlation

Multiple linear regression

Data Collection Summary:

Outcome(s) and other measures

1. Measured REE [(VO2, l/min), VCO2 (l/min; ml/kg/min), RQ, ventilation (l/min)].

2. Predicted RMR using Harris-Benedict, Boothby, and Kleiber

3. Independent variables of weight, height, age, BMI,and fat-free mass, fat mass

Blinding Used: No

Description of Actual Data Sample:

N= 80 women (age 41.6+/-10)

Moderately obese (188 +/- 38% recommended wt) women

Summary of Results:

ANTHROPOMETRIC

	Nonobese	Obese
Wt,kg	56.6 ±4.4	104.6 ± 20.5
Fat,kg	17.4 ± 1.7	50.7 ± 13.7
FFM,kg	38.1 ± 3.6	53.3 ± 6.0
TBK/HT,mEq/cm	15.1 ± 0.0	17.1 ± 2.1
TBW/HT,L/cm	0.2 ± 0.0	0.27 ± 0.0
K/FFM,mEq/kg	61.5 ± 2.2	51.9 ± 8.2

REE

The mean measured REE was 1,746 ± 260 kcal/d. Measured was 99.3 ± 12.2% of Harris-Benedict predictions, 98.8 +/- 12.1% of Boothby’s prediction, and 97.9 ± 12.2% of Kleiber’s prediction.

While the mean predicted value was highly accurate, prediction of individual values was far less so. The correlation coefficient between measured REE and the predicted estimates were r=.59 for Harris-Benedict, r=.59 for Boothby, and r=.58 for Kleiber.

Frequency distribution reveals that only 59% of patients’ measured REE values were within ± 10% of predicted Harris-Benedict values.

REE and body composition

REE per kg of FFM was 33.4 ± 4.9 kcal/kg/d. A stepwise multiple regression of the dependent variable REE on the independent variables of wt, ht, age, fat, and FFM reveals that 34% of the variance in REE could be explained by wt and age and that wt accounted for 27% of it.

FFM accounted for 26% of the variance in REE, and the addition of fat accounted for only an additional 4%.

Additional analysis showed that wt was highly correlated with both fat (r=.93) and FFM (r=.86). Fat and FFM were also highly correlated with each other (r=.65)

Author Conclusion:

“Our data indicate that commonly used equations for the prediction of REE are not satisfactory for use with moderately obese individuals. Fewer than 60% of our patients had measured REEs within 10% of predicted values.”

“There are at least 2 reasons why the Harris-Benedict equations failed to predict the energy expenditure of obese individuals: (1) Harris and Benedict’s subjects were 239 healthy, nonobese individuals whose body composition did not resemble that of obese persons; and (2) Harris and Benedict’s regression equation described a normal population and not individuals in that population.”

“We also evaluated nine other formulae derived exclusively from obese population, non of which improved the accuracy of prediction.”

“Our finding suggest that the REE of obese persons is most closely related to weight……Weight accounted for only 27% of the variance in measured REE, and no combinations of anthropometric and/or body composition parameters could account for more than 34% of the variance. FFM accounted for more of the variance in REE than did fat but predicted no better than weight alone.”

“Prediction from the Boothby equations and the Kleiber equation were virtually identical to those of the Harris-Benedict predictions. This similarity of prediction among the three formulae was probably due to the similarity of their assumptions of normal body composition and their inclusions of common indices that correlate with body composition in normals.

Funding Source:

Government:

NICHD, NCI

Industry:

Sandoz Nutrition Company

Pharmaceutical/Dietary Supplement Company:

Not-for-profit

Reviewer Comments:

Strengths:

Comparison of several equations was performed.
Sophisticated, appropriate statistics.
Body composition was assessed in 3 ways and was considered in the analysis.
A thorough discussion on 3 REE equation.

Generalizability/Weaknesses:

IC measurements were not described in sufficient details (room temp, if subjects were rested before test…etc.)
Physical activities, dietary intake prior to IC studies were not assessed, monitored, or controlled.
Smoking, or other substances use were not monitored
Limitations were not discussed.

Quality Criteria Checklist: Primary Research
Relevance Questions
	1.	Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies)	Yes
	2.	Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about?	Yes
	3.	Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice?	Yes
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	Yes

Validity Questions
1.	Was the research question clearly stated?		Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	N/A
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	N/A
	1.3.	Were the target population and setting specified?	N/A
2.	Was the selection of study subjects/patients free from bias?		Yes
	2.1.	Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study?	N/A
	2.2.	Were criteria applied equally to all study groups?	N/A
	2.3.	Were health, demographics, and other characteristics of subjects described?	N/A
	2.4.	Were the subjects/patients a representative sample of the relevant population?	N/A
3.	Were study groups comparable?		Yes
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	N/A
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	N/A
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	N/A
	3.4.	If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis?	N/A
	3.5.	If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.)	N/A
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	N/A
4.	Was method of handling withdrawals described?		No
	4.1.	Were follow-up methods described and the same for all groups?	N/A
	4.2.	Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.)	N/A
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	N/A
	4.4.	Were reasons for withdrawals similar across groups?	N/A
	4.5.	If diagnostic test, was decision to perform reference test not dependent on results of test under study?	N/A
5.	Was blinding used to prevent introduction of bias?		Yes
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	N/A
	5.2.	Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.)	N/A
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	N/A
	5.4.	In case control study, was case definition explicit and case ascertainment not influenced by exposure status?	N/A
	5.5.	In diagnostic study, were test results blinded to patient history and other test results?	N/A
6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?		No
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	N/A
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	N/A
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	N/A
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	N/A
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	6.6.	Were extra or unplanned treatments described?	N/A
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	N/A
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	N/A
7.	Were outcomes clearly defined and the measurements valid and reliable?		No
	7.1.	Were primary and secondary endpoints described and relevant to the question?	N/A
	7.2.	Were nutrition measures appropriate to question and outcomes of concern?	N/A
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	N/A
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	N/A
	7.5.	Was the measurement of effect at an appropriate level of precision?	N/A
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	N/A
	7.7.	Were the measurements conducted consistently across groups?	N/A
8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?		Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	N/A
	8.2.	Were correct statistical tests used and assumptions of test not violated?	N/A
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	N/A
	8.4.	Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)?	N/A
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	N/A
	8.6.	Was clinical significance as well as statistical significance reported?	N/A
	8.7.	If negative findings, was a power calculation reported to address type 2 error?	N/A
9.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	N/A
	9.2.	Are biases and study limitations identified and discussed?	N/A
10.	Is bias due to study's funding or sponsorship unlikely?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	N/A
	10.2.	Was the study free from apparent conflict of interest?	N/A