EAL

EE: Harris-Benedict (2005)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

What is the extent to which the actual, measured REE (i.e., caloric needs of stable patients, not experiencing significant clinical stress) can be accurately estimated using the Harris-Benedict and Kleiber predictive formulae?

Inclusion Criteria:

Healthy

Exclusion Criteria:

Non-consent

Description of Study Protocol:

Definitions:

“Steady state”- Five consecutive, stable 1-minute measurements of VO2 and VCO2 within a range of ± 5%

“Resting energy expenditure” – the metabolic rate (kcal/day) of an individual when lying in bed, with the skeletal muscles completely supported and ag rest, greater than 2 h after the most recent meal.

“Harris-Benedict” equation”: Matches studies definition

“Clinically stable” – Defined as “afebrile and no major trauma, burn, skeletal fracture or recent surgery within past 5 days”

“Metabolic body size” – kcal/kg ^0.75 /day

ANTHROPOMETRIC:

Ht measured ?: Not reported
Wt measured ? Not reported
Fat-free mass measured? Not reported

CLINICAL:

Identified “clinically stable”
Body temperature? Not reported

Resting energy expenditure:

IC type: Used a non-rebreathing valve and nose clips. Portable indirect calorimter that measures partial pressure of O2 and CO2 in expired air by a polarographic oxygen sensor and nondispersive infrared analysis. A bias flow turbine volume transducer determines minute ventilation, while temperature, barometric pressure and time are measured by independent instruments w/in the system. A continuous aliquot of expired air (500 cc/min) is drawn from the gas colletin chamber, through the gas analyzers and past the volume and temperature sensors; a programmable calculator integrates all measurements.

Rest before measure: 30 min

Measurement length:1 minute

Fasting length: >2 hr following meal

Exercise condition: Not reported

Room temp: Not reported

No. of measures:& were they repeated (CV identified)? 5 consecutive 1 min readings and w/in range ± 5%; the mean values for VO2 and VCO2 of only the equilibrated data points were used to calculate REE by the abbreviated Weir Formula.

Equipment Calibration?: Yes, were calibrated to independent instruments and gases w/in range of values present in expired air. Measurements w/in ± 1.5% of RQ; ± 5.0% of O2 and CO2 productions in study conditions (i.e., O2 concentration ± 21%; tidal volume >350 cc)

Training of measurer? “a single technician”

Subject training of measuring process? Not reported

Intervening factor: Diseases

Data Collection Summary:

Measured REE [(VO2, l/min), CO2 (l/min; ml/kg/min), RER, ventilation (l/min)].
Predicted REE using HB, Kleiber
Independent variables of weight, height, age and ideal weight

Blinding used: No blinding

Description of Actual Data Sample:

Patient sample:

N= 200 pts (100 males; 100 females)

Diseases represented: 47/100 and 62/100 men and women, respectively had carcinoma w/ a solid tumor; 3 in each gender had a non-solid tumor. IBD, Pancreatitis, Biliary Disease, GI Obstruction, Ulcer, Liver, Cardiac and Renal diseases were represented by other patients.

Control Sample: N=72 (20 males; 52 females)

Demographics:

Patients

Males:

Mean age: 50.9 ± 18.7
Range: (NA)

Females:

Mean age: 54.8 ±17.0
Range: (NA)

Controls

Males:

Mean age: 26.6 ± 5.4
Range: (NA)

Females:

Mean age: 25.9 ±3.8
Range: (NA)

ANTHROPOMETRIC

Patients, women (n=100)

	Mean±SD
Wt, kg	57.9±13.0
Ht, cm	161.8±7.5
BMI	21.6+2.7

Patients, men (n=100)

	Mean±SD
Wt, kg	69.5 ±13.7
Ht, cm	175.0±7.6
BMI	NA
Ideal wt	91.1±19.8

Controls, women (n=52)

	Mean±SD
Wt, kg	57.5±6.9
Ht, cm	164.7±6.5
BMI	NA
Ideal wt	103.9±9.4

Controls, men (n=20)

	Mean±SD
Wt, kg	78.3 ±13.5
Ht, cm	179.9±8.5
BMI	NA
Ideal wt	105.8±11.8

Summary of Results:

Used Dunnet’s procedure for the comparison of all treatment means with a control mean; the control was the measured REE. [NOTE: Kleiber prediction information not abstracted from table d/t project scope].

Female patient sample (n=100):

	Measured	HB Predict
Kcal/day	1176±243	1225±145
Kcal/kg/day	21.2±4.6	22.0±3.2
Kcal/kg ^0.75/day	57.6±10.5	58.9±8.5

Differences b/t means of measured REE and all HB predictions were not statistically significant.

Male patient sample (n=100):

	Measured	HB Predict
Kcal/day	1445±292	1494±250
Kcal/kg/day	22.4±3.8	23.1±2.7
Kcal/kg ^0.75/day	63.4±10.0	65.3±6.4

Female Control sample (n=52):

	Measured	HB Predict
Kcal/day	1313±110	1367±76*
Kcal/kg/day	23.1±2.7	23.9±1.8
Kcal/kg ^0.75/day#	63.2±5.9	65.3±4.2

*Female control sample showed statistically significant differences b/t HB predictors and measured REE (kcal/day)(P<0/01)

#P<0.05 vs. measured REE

Male Control sample (n=20):

	Measured	HB Predict
Kcal/day	1791±239	1851±223
Kcal/kg/day	23.2±2.4	24.0±1.2
Kcal/kg ^0.75/day	68.7±6.1	70.6±2.6

The only significant difference observed in the male control sample was b/t measured REE when normalized to metabolic body size and Kleiber predictor (P<0.05).

INDIVIDUAL CORRELATIONS

Each predictive equation was less accurate in individual pt than for individual normal control subjects to estimating REE ±10%

Female patients:

REE was accurately estimated (±10% of measured value) in 60% female patients.

Difference Range:

Underestimate REE by 42%

Overestimate REE by 46%

Female controls:

REE was accurately estimated (+10% of measured value) in 81% female controls.

Difference Range:

Underestimate REE was not underestimated by >+10% of measured REE for female controls

Overestimate REE of 18% by HB

Male patients:

REE was accurately estimated (±10% of measured value) in 60% of cases

Difference Range:

Underestimate REE by 26% to Overestimate REE by 66%

Male controls:

The HB formula predicted mREE within ±10% for 80% cases

Difference Range:

Underestimate REE by 10%

Overestimate REE by 66%

Author Conclusion:

As stated by the author in body of report:

“In our study, comparisons between HB predictors and our clinical measurements are appropriate since environmental and technical conditions were comparable.”

“Multiple correlation coefficient for HB male subjects to be +0.766 and the multiple correlation coefficient for the females to be +0.524. Therefore, 59% of the total variance in REE can be ascribed to the combined variance due to height, weight, and age for [Harris-Benedict’s] healthy males (R2=0.587) and similarly, 28% of the total variance in measured REE can be ascribed to the combined variance d/t the same independent variables in females(R2=0.275).”

“Although the differences in means were not statistically significant, actual resting caloric expenditure would be overestimated by at least 10% for 28% of the clinically stable male patients; and 20% of the control subjects using HB. REE (and therefore caloric requirements) would be substantially underestimated for 12% of the hospitalized males; but none of the controls.” [REVIEWERS NOTE: Do not understand the distinction between hospitalized vs. initial description of “clinically stable male patients?]

“The HB formula yields an overestimate of REE for 32% of female pt and 18% of normal female subjects”

“Due to the low variance in predicted REE among female control sample, differences b/t the means of both samples were more narrow than hospitalized patients.”

“Both the HB and Kleiber predictors over or underestimate measured REE by greater than 10% for a substantial number of clinically stable patients . . . delivery of calories below actual requirements will result in inadequate nutritional repletion or maintenance.”

Funding Source:

Government:

NIH

Industry:

Beckman Instruments

Other:

Reviewer Comments:

Strengths (considering control group samples only):

Control samples (male and female) were within the mean age of 1918 HB men and women samples; this study’s current control sample had a narrower range.
Described IC procedures and were w/in range of +5 %.
Comparable environmental conditions to HB reported

Generalizability/Weaknesses:

“Patient sampling has risk of referral filter bias (i.e., samples at a tertiary care center different than general population); Also a funding bias risk since the IC used was manufactured by funder
Lacked description of how they obtained control sample subjects so limited generalizability as unknown about types of sampling bias from methods.
Fasting length only 2 hrs for controls and did not restrict physical activity prior to testing for controls; No description regarding medications; Had ht and wt but did not calculate BMI.

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?		No
	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?		N/A
	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?		No
	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?		Yes
	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?		No
	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?		No
	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