EAL

AWM: Estimating Resting Metabolic Rate (RMR) (2014)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To examine the accuracy and precision of 12 equations or tables for predicting resting metabolic rate in obese persons.

Inclusion Criteria:

Understand and give written consent
Twenty percent above desirable weight (according to 1959 Metropolitan Life Insurance tables)
No self-reported medical history or previous or present health problems that might affect metabolic rate
No medical history of dieting or weight loss.

Exclusion Criteria:

Refusal to consent
Not meeting inclusion criteria
Diseases in subjects that were excluded: Thyroid disorders, diabetes mellitus
Medications that were excluded: Thyroid hormones, antihistamines and certain antidepressants.

Description of Study Protocol:

Recruitment

Data from outpatients who were enrolling in a weight loss program and who underwent a battery of tests, including indirect calorimetry, prior to enrollment. Data collected between 1984 and 1988.

Design

Correlational study.

Statistical Analysis

To compare calculated vs. measured RMR, the measured RMRs were regressed on RMRs predicted from each of the published equations
- An equation was accurate to the degree that the resulting linear regeression equation has an intercept of zero and a slope of one, indicating there is neither a constant bias in the estimate nor a bias whose magnitude or direction depends on the value of RMR
- The equation is precise to the degree that it leaves little unexplained variance in the dependent variable
Standard statistical tests were used to determine whether the intercept and slope were different from zero and one
Standard error of the estimate for each equation is the square root of 1-R2
Paired T-tests were used to test the mean difference between measured and predicted RMR for each equation.

Data Collection Summary:

Timing of Measurements

One measurement.

Dependent Variables

Predicted RMR using 12 equations: Bernstein, Cunningham, HB, James, Mifflin, Owen, Pavlou (2), Aub and Dubois, Boothby, Fleisch, Robertson and Reid
- Weight: Measured with subjects in underclothes to nearest 0.1kg
- Height: Measured without shoes to nearest 0.1cm.

Independent Variables

Measured RMR
- IC type: Beckman
- Equipment of Calibration: Not addressed
- Coefficient of variation using standard gases: Not addressed
- Rest before measure: 30 minutes
- Measurement length: Not specified
- Steady state: Not addressed
- Fasting length: 12 hours to 14 hours
- Various times in the day: Morning
- Exercise restrictions XX hours prior to test? None during measurement
- Room temperature: Constant
- Number of measures within the measurement period: Not specified
- Were some measures eliminated? No
- Were a set of measurements averaged? Not specified
- Coefficient of variation in subjects measures? Yes
- Training of measurer? No
- Subject training of measuring process? No
- Monitored heart rate? No
- Body temperature? No
- Medications administered? No.

Description of Actual Data Sample:

Initial N: N=127 (73 females, 54 males)
Final N: N= 126 (73 females, 53 males, one male outlier excluded from analysis)
Age
- Females: 38.5±11.4 years
- Males: 38.6±10.6 years
Ethnicity: Not described
Other relevant demographics: None described
Anthropometrics: Mean±SD

	Women	Men
Weight(kg)	96.7±12.4	129.9±27.7
BMI	35.2±7.2	45±8.5
MRMR	1,626±274	2,073±328
Height (cm)	165.3±6.6	176.9±7.7

Location: Obesity Research Center, New York.

Summary of Results:

Predicted RMR Equations

Of the predicted equations, six had intercepts or slopes that were significantly different from zero and one, respectively. With only two exceptions (Cunningham for men and Owen et al for men), the equations accounted for between 56% and 63% of the variance in measured RMR.

The Roberson and Reid equation and the Fleisch equation performed best in this obese sample.

Men

Six of the 12 prediction equations had intercepts or slopes that were significantly different from zero or one, respectively: Bernstein, Cunningham, HB, James, Pavlou(a), Pavlou(b).

Group mean errors of eight of the 12 equations were negative and statistically significant by T-test (P<0.05), which indicates that RMRs were overestimated in this sample.

Women

Four of the 10 equations had intercept or slopes that differed significantly from zero or one: Cunningham, James, Mifflin-St. Jeor, Owen.

Seven of 10 had a significant group mean error and six of nine gave a negative mean error, which indicates that the predicted RMR tended to be too high (P=0.26). With only two exceptions, the equations accounted for between 56% and 63% of the variance in measured RMR.

**Regression Coefficients (±Standard Error), R2 and Mean Error for Resting Metabolic Rate Equations Applied to an Obese Sample Population**
Group and equations	Intercept	Slope	R²	Mean error
MEN
Aub and Dubois	-227±265	1.02±0.117	0.59	-180**
Bernstein et al	655±160	0.71±0.079**	0.60	87
Boothby et al	-186±239	1.01±0.106	0.63	-159**
Cunningham	-1,877±693**	1.80±0.332*	0.38	-9
Fleisch	-255±263	1.10±0.124	0.60	-37
Harris and Benedict	563±172**	0.61±0.068**	0.60	-408**
James	378±185*	0.70±0.075**	0.62	-359**
Mifflin et al	149±205	0.83±0.092	0.60	-132 **
Owen et al	194±245	0.84±0.110**	0.53	-132 **
Pavlou et al (a)	663±160**	0.60±0.067**	0.60	-289 **
Pavlou et al (b)	727±162**	0.56±0.67	0.57	-321 **
Robertson and Reid	-154±244	1.08±0.118	0.61	21
WOMEN
Aub and Dubois	-122±173	0.99±0.097	0.59	-135**
Bernstein et al	-29±160	1.20±0.115	0.60	244**
Boothby et al	-43±168	0.97±0.098	0.58	-87**
Cunningham	-1,565±330**	1.98±0.205**	0.56	18
Fleisch	-77±171	1.01±0.101	0.58	-56*
Harris and Benedict	97±147	0.90±0.085	0.60	-81**
James	350±131**	0.75±0.075**	0.57	-82**
Mifflin et al	310±128	0.80±0.076**	0.60	-23
Owen et al	-294±198	1.29±0.132*	0.57	137**
Robertson and Reid	-77+164	1.06+0.101	0.60	18

* P<0.05

**P<0.01

Author Conclusion:

Most published equations overestimated RMRs for the obese men in our sample. For the women, the trend was similar but not as strong. This difference in results may be a consequence of the greater obesity of the male sample whose mean body mass index was 41.5, compared with 35.2 for women. The correlations between estimated and measured values indicate that 30% to 40% of the variability in measured RMR remains unexpected by height, weight, age and various transformations of these variables, such as body surface area.

Another question that arises from the results of our study is why the Robertson and Reid equation performed so well compared with other equations. A methodologic difference may be responsible. The protocol of Robertson and Reid for determining RMR involved taking repeated measurement procedures and eliminated elevations in RMR caused by anxiety during testing. Thus, the measure RMR values used in developing the tables of Robertson and Reid were probably lower than those of those of other studies.

For adults who are more than 20% above desirable weight or whose BMI exceeds 28, we recommend the Robertson and Reid equation or the Fleisch equation, because they appear to offer the best estimates in an obese population.

Funding Source:

University/Hospital:

Columbia University, St. Lukes

Reviewer Comments:

Strengths

Appropriate statistics
Good sample size for validation study
Through discussions; conclusions were supported by results.

Generalizability/Weaknesses

Measuring process was not described in sufficient details
Physical activity, smoking status were not monitored

Evidence Analyst Note

In the study by Heshka selecting obese individuals, 22 females (i.e., 32% of female subgroup) potentially represented non-obese weight classification (i.e., BMI 24-28). While enrollment criteria was 20% above desirable body weight based on 1959 Metropolitan Life tables, analysts were unable to determine ifmbody fat percentage or “obesity” criteria met and if overweight categories were excluded in data. Therefore, data for women was abstracted as non-obese and obese combined weight data.

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?	???
2.	Was the selection of study subjects/patients free from bias?		???
	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?	Yes
	2.2.	Were criteria applied equally to all study groups?	Yes
	2.3.	Were health, demographics, and other characteristics of subjects described?	???
	2.3.	Were health, demographics, and other characteristics of subjects described?	???
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
	3.	Were study groups comparable?	Yes
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
	3.1.	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?	Yes
	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?	Yes
	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.)	Yes
	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.)	Yes
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	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?	Yes
4.	Was method of handling withdrawals described?		Yes
	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?	Yes
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	Yes
	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?	N/A
5.	Was blinding used to prevent introduction of bias?		N/A
	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.)	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
	5.3.	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?	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.	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?	Yes
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	Yes
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	Yes
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	Yes
	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?	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
	6.6.	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
	6.7.	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
	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?	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?	Yes
	7.1.	Were primary and secondary endpoints described and relevant to the question?	Yes
	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?	???
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	???
	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?	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?	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)?	Yes
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	Yes
	8.6.	Was clinical significance as well as statistical significance reported?	Yes
	8.6.	Was clinical significance as well as statistical significance reported?	Yes
	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