EAL

CI: Individual Equations (2010)

Citation:

Frankenfield DC, Coleman A, Alam S, Cooney R. Analysis of estimation methods for resting metabolic rate in critically ill adults. J Parenter Enteral Nutr. 2009; 33: 27.

PubMed ID: 19011147

Study Design:

Concurrent comparative study.

Class:

C - Click here for explanation of classification scheme.

Quality Rating:

POSITIVE: See Quality Criteria Checklist below.

Research Purpose:

The purpose of this study was to compare several equations for predicting resting metabolic rate in a large sample of critically ill adults to determine which have clinical usefulness.

Inclusion Criteria:

Patients were included if they were:

Admitted to an adult intensive care unit (ICU)
At least 18 years old
Required mechanical ventilation
Had orders written and implemented for enteral or parenteral nutrition.

Exclusion Criteria:

Patients were excluded if:

An air leak existed in their ventilation circuit
Their Fi0₂ was more than 60%
They were undergoing intermittent hemodialysis
They were shivering or agitated
They had limited support orders written
They had paraplegia and quadriplegia
They had cystic fibrosis.

Description of Study Protocol:

Recruitment: Patients meeting inclusion criteria between September 2006 and December 2007
Design: Standardized indirect calorimetry measurements were made in ventilated, adult critical care patients. Resting metabolic rate was calculated using nine equations. The calculated results were compared to the indirect calorimetry measurements.
Statistical analysis: Eight equations were validated simultaneously. The result of each equation was compared with the measured value of resting metabolic rate for bias, precision and accuracy rate.

Data Collection Summary:

Dependent Variable

The calculated difference between each predicted energy expenditure equation and the actual measured energy expenditure.

Independent Variables

Equations used in the study included:

Harris Benedict (basic)
- Men: 13.75(weight) + 5(height) - 6.8(age) + 68
- Women: 9.6(weight) + 1.8(height) - 4.7(age) + 655
Harris Benedict (variants): HBEa(25) substitutes adjusted body weight in obese patients calculated as (actual weight - ideal weight)0.25 + ideal weight
- HBEa(25) x 1.25 uses the HBEa(25) value and multiplies it by a 1.25 stress factor
- HBEa(50) substitutes adjusted body weight in obese patients calculated as (adjusted weight - ideal weight)0.50 = ideal weight
- HBEa(50) x 1.25 uses the HBEa(5) value and multiplies it by a 1.25 stress factor
Mifflin St. Jeor
- Men: 10(weight) + 6.25(height) - 5(age) + 5
- Women: 10(weight) + 6.25(height) - 5(age) - 161
American College of Chest Physicians (ACCP)
- 25kcal per kg (actual weight in obese subjects)
- 25kcal per kg (adjusted weight in obese subjects)
Swinamer: BSA (941) - age(6.3) + T(104) + RR(24) + Vt(804) - 4,243
Ireton-Jones: Weight(f) - age(10) + male(281) + trauma(292) + burns(851)
Brandi: HBE(0.96) + HR(7) = Ve(48) - 702
Penn State
- PSU(HBE) = HBE(0,85) + Tmax(175) + Ve(33) - 6,344
- PSU(HBEa) = HBEa(1.1) = Tmax(140) + Ve(32) - 5,340
- PSU(m) = Mifflin(0.96) = Tmax(167) + Ve(31) - 6,212
Faisy: Weight(8) + height(14) + Ve(32) + T(94) - 4,834.

BSA: Body surface area in meters squared
HBE: Harris Benedict equation
HBEa: Harris Benedict equation adjusted for weight
HR: heart rate in beats per minute
Ht: Height
PSU: Penn State equation
RR: Respiratory rate in breaths per minute
T: Body temperature in degrees centigrade
Tmax: Maximum body temperature in past 24 hours, centigrade
Ve: Expired minute ventilation
Vt: Tidal volume in L per breath
Wt: Weight.

Control Variables

Energy expenditure measured by indirect calorimetry.

Description of Actual Data Sample:

N: 202 (55% male)
Age: 51% were aged at least 60 years
Ethnicity: 95% were Caucasian.

Other Relevant Demographics

Variable	Non-Obese Young (N=52)	Obese Young (N=47)	Non-obese Elderly (N=52)	Obese Elderly (N=51)
Gender (percentage male)	65	62	54	37
Height (cm)	173±9 (150 to 190)	176±11 (152 to 195)	168±10 (145 to 185)	167±10 (150 to 188)
Weight (kg)	75±13 (47 to 104)	124±43 (80 to 334)	71±12 (42 to 92)	102±19 (71 to 164)
BMI (kg/m²)	25±3 (15.5 to 29.7)	40±13 (30 to 112)	25±3 (16.7 to 29.8)	36±6 (30 to 64.1)
Age (years)	39±13 (18 to 59)	44±12 (18 to 59)	75±9 (60 to 95)	70±8 (60 to 87)

Location

Penn State MS Hershey Medical Center.

Summary of Results:

Maximum Errors for Each Equation (Percentage Difference From Measured Value)

Equation	Young Non-Obese Min	Young Non-Obese Max	Young Obese Min	Young Obese Max	Elderly Non-Obese Min	Elderly Non-Obese Max	Elderly Obese Min	Elderly Non-Obese Max
HBE	-41	20	-31	65	-34	16	-50	22
HBE x1.25	-27	50	-14	106	-18	45	-38	53
HBEa(25)	-41	20	-49	11	-34	16	-57	0
HBEa(25) x1.25	-27	50	-36	11	-18	45	-46	24
HBEa(50)	-41	20	-43	10	-34	16	-55	5
HBEa(50) x1.25	-26	50	-29	38	-18	45	-43	31
Mifflin	-43	19	-34	34	-43	3	-53	17
Mifflin x1.25	-29	49	-17	68	-29	28	-41	46
ACCP (weight)	-33	42	-9	160	-12	40	-36	104
ACCP (MAW)	-33	42	-35	9	-12	40	-47	235
Swinamer	-17	34	-22	41	-26	42	-25	58
Ireton-Jones	-31	73	-29	26	-20	70	-38	43
PSU (HBE)	-21	27	-20	48	-24	37	-32	50
PSU (HBEa)	-15	40	-31	18	-21	43	-39	31
PSU (m)	-25	32	-19	34	-31	39	-32	48
Brandi	-18	34	-19	67	-29	28	-33	39
Faisy	-18	33	-27	30	-20	44	-28	52

Unbiased Equations Used in the Study

Harris Benedict x 1.25 unbiased only for non-obese young groups
Harris Benedict_adjusted(50) x 1.25 was unbiased for all plus non-obese young, obese young, and obese elderly groups
Mifflin-St. Jeor x 1.25 was unbiased for all, plus non-obese young, obese young, non-obese elderly and obese elderly groups
Ireton-Jones was unbiased for all and for the obese elderly group
PSU (HBE) unbiased for all, obese young, non-obese and obese elderly groups
PSU (HBE_adjusted) unbiased for all
PSU (m) unbiased for all as well as the four subgroups (obese and non-obese young and obese and non-obese elderly)
Brandi was unbiased only for non-obese young and non-obese elderly
Faisy was unbiased for young subjects (obese and non-obese).

Precise Equations Used in the Study

Precise equations were within 15% of measured REE:

HBE x 1.25 for elderly non-obese subgroup
HBE _adjusted(25) x 1.25 for all as well as the young obese and elderly non-obese subgroups
HBE _adjusted(50) x 1.25 for all as well as young obese and elderly non-obese subgroups
Mifflin-St. Jeor x 1.25 for all as well as non-obese subgroups (young and elderly)
ACCP (wt) precise only for young non-obese subgroup
ACCP (adjusted weight) precise only for overall and the young non-obese subgroup
Swinamer precise for all except elderly obese subgroup
Ireton-Jones precise for elderly obese and non-obese and young obese
PSU (HBE) precise for all except elderly obese
PSU (HBE _{adjusted weight}) and PSU (m) precise for overall as well as all subgroups
Brandi precise for overall as well as subgroups except elderly obese
Faisy precise for overall and for young obese and non-obese subjects.

Author Conclusion:

The most accurate equation across the patient subgroups and the statistical measures is the PSU(m) equation which is Mifflin(0.969) + Tmax(167) + Ve(31) - 6212 where Tmax is the maximum body temperature in the previous 24 hours and Ve is minute ventilation at the time of measurement as read from the ventilator, not the calorimeter. In some subgroups and measures, the other equations worked equally well. The exception for all the equations is the group of patients over the age of 60 with BMI more than 30kg/m².It was difficult to predict energy needs in obese patients, no matter which equation was used.
Based on these findings, the authors recommend the PSU(m) equation for use in critical care assessment.

Funding Source:

University/Hospital:

Penn State M.S. Hershey Medical Center

Reviewer Comments:

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
	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
	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
	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
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	Yes

Validity Questions
	1.	Was the research question clearly stated?	Yes
1.	Was the research question clearly stated?		Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	Yes
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	Yes
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	Yes
	1.3.	Were the target population and setting specified?	Yes
	1.3.	Were the target population and setting specified?	Yes
	2.	Was the selection of study subjects/patients free from bias?	Yes
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?	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?	Yes
	2.2.	Were criteria applied equally to all study groups?	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?	Yes
	2.3.	Were health, demographics, and other characteristics of subjects described?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	Yes
	3.	Were study groups comparable?	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
	3.1.	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
	3.2.	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
	3.3.	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
	3.4.	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
	3.5.	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")?	Yes
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	Yes
	4.	Was method of handling withdrawals described?	N/A
4.	Was method of handling withdrawals described?		N/A
	4.1.	Were follow-up methods described and the same for all groups?	N/A
	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
	4.2.	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
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	N/A
	4.4.	Were reasons for withdrawals similar across groups?	N/A
	4.4.	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
	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.	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
	5.1.	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.)	Yes
	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.)	Yes
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	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
	5.4.	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?	Yes
	5.5.	In diagnostic study, were test results blinded to patient history and other test results?	Yes
	6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?	Yes
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
	6.1.	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
	6.2.	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
	6.3.	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
	6.4.	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?	Yes
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	Yes
	6.6.	Were extra or unplanned treatments described?	Yes
	6.6.	Were extra or unplanned treatments described?	Yes
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	Yes
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	Yes
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	Yes
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	Yes
	7.	Were outcomes clearly defined and the measurements valid and reliable?	Yes
7.	Were outcomes clearly defined and the measurements valid and reliable?		Yes
	7.1.	Were primary and secondary endpoints described and relevant to the question?	N/A
	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?	Yes
	7.2.	Were nutrition measures appropriate to question and outcomes of concern?	Yes
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	Yes
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	Yes
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	Yes
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	Yes
	7.5.	Was the measurement of effect at an appropriate level of precision?	Yes
	7.5.	Was the measurement of effect at an appropriate level of precision?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	Yes
	7.7.	Were the measurements conducted consistently across groups?	Yes
	7.7.	Were the measurements conducted consistently across groups?	Yes
	8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?	Yes
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?	Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	Yes
	8.2.	Were correct statistical tests used and assumptions of test not violated?	Yes
	8.2.	Were correct statistical tests used and assumptions of test not violated?	Yes
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	Yes
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	Yes
	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
	8.4.	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
	8.5.	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
	8.6.	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
	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.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	Yes
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	Yes
	9.2.	Are biases and study limitations identified and discussed?	Yes
	10.	Is bias due to study's funding or sponsorship unlikely?	Yes
10.	Is bias due to study's funding or sponsorship unlikely?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes