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

Citation:

Weijs PJ. Validity of predictive equations for resting energy expenditure in US and Dutch overweight and obese class I and II adults aged 18-65 years. Am J Clin Nutr. 2008; 88(4): 959-970.

PubMed ID: 18842782
 
Study Design:
Diagnostic, Validity or Reliability Study
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
To analyze which resting energy expenditure (REE) predictive equation was the best alternate to indirect calorimetry in U.S. and Dutch adults aged 18 to 65 years with a body mass index (kg/m2) of 25 to 40.
Inclusion Criteria:
  • BMI higher than 25kg/m2 but less than 40kg/m2
  • Age 18 to 65 years
  • Provided written informed consent
Exclusion Criteria:
Not described.
Description of Study Protocol:

Recruitment

Subjects were included from different weight loss studies at the Nutrition Lab of the Department of Nutrition and Dietetics, University of Applied Science, Amsterdam, Netherlands between April 3, 2006 and March 27, 2008.

Design

Diagnostic, validity or reliability study.

Blinding Used

Implied with measurements.

Statistical Analysis

  • Subject characteristics were analyzed with an independent samples T-test.
  • A prediction between 90% and 110% of the REE measured was considered an accurate prediction, a prediction less than 90% of  the REE measured was classified as an under-prediction and a prediction higher than 110% of the REE measured was classified as an over-prediction
  • The percentage of patients that had an REE predicted within ±10% of the REE measured was considered a measure of accuracy on an individual level
  • Data were analyzed using SPSS version 14.0 and Bland-Altman with MedCalc software.
Data Collection Summary:

Timing of Measurements

All measurements made on the same day for each individual.

Dependent Variables

  • Indirect calorimetry measurements were performed with a ventilated hood system (Vmax Encore n29; Viasys Healthcare, Houten, Netherlands), which was calibrated for volume and with two standard gases every day before use. The subjects were in a supine position and awake and had fasted overnight or for four hours before the measurement was made if the measurements could not be performed before noon. Subjects had not been physically active.
  • Oxygen consumption and carbon dioxide production were measured and energy expenditure was calculated by using the Weir formula
  • Resting energy expenditure (REE) predictive equation: A PubMed search was used for a systematic review on Mesh derived key terms such as Energy Metabolism, Basal Metabolism and Indirect Calorimetry and additional terms such as predict, estimate, equation and formula
  • Applied limitations were English language and humans and age of 18 or more years.From each included study the best performing equations based on the highest value for explained variance (R2) were included. A total of 27 predictive equations (nine of which were based on FFM) were included.  
    • Harris-Benedict 1919
    • Harris-Benedict 1984
    • Bernstein et al
    • Bernstein et al, FFM
    • Owen et al
    • Owen et al, FFM
    • Mifflin et al
    • Mifflin et al, FFM
    • Livingston and Kohlstadt
    • Schofield, weight
    • Schofield, weight and height
    • FAO, weight
    • FAO, weight and height
    • Henry, weight
    • Henry, weight and height
    • Muller et al
    • Mullet et al, BMI
    • Muller et al, FFM
    • Muller et al, BMI and FFM
    • Korth et al
    • Korth et al, FFM
    • De Lorenzo et al
    • Lazzer et al
    • Lazzer et al, FFM
    • Huang et al
    • Huang et al, FFM
    • Johnstone et al, FFM
  • Studies were also judged for the methodological quality of the calorimetry procedure. 
Independent Variables

Overweight and obese class I and II adults aged 18 to 65 years.
Description of Actual Data Sample:
  • Initial N: 447 (239 in US group, 208 Dutch group)
  • Attrition (final N): 447 (239 in the US group and 208 in the Dutch group). Validation was based on 180 women and 158 men from the United States and on 154 women and 54 men from the Netherlands
  • Age: Mean age in the American group 43.7 years vs. 40.8 in the Dutch group, all aged less than 65 years
  • Ethnicity: Dutch and American 
  • Anthropometrics: Mean BMI (kg/m2) in the American group 29.5 vs. 30.8 in the Dutch group, BMI range of 25kg/m2 to 40kg/m2
  • Location: United States and The Netherlands.

 

Summary of Results:

Key Findings

Most accurate and precise for:
  • U.S adults: The Mifflin equation (prediction accuracy 79%, bias: -1.0%; RMSE: 136kcal per day
  • Overweight Dutch adults: The FAO/WHO/UNU weight equation (predictive accuracy 68%, bias -2.5%, RMSE: 178kcal per day)
  • Obese Dutch adults was the Lazzer equation (prediction accuracy 69%, bias:-3.0% RMSE: 215kcal per day).

 

 

 

Author Conclusion:
For U.S adults aged 18 to 65 years with a body mass index of 25 to 40, the REE can best be estimated with the Mifflin equation. For overweight and obese Dutch adults, there appears to be no accurate equation.

 
Funding Source:
University/Hospital: Hogeschool van Amsterdam, The Netherlands
Reviewer Comments:
Questionable validity of indirect calorimeter.
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? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? 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
  2.2. Were criteria applied equally to all study groups? 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
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) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  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")? Yes
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  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%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? Yes
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? 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
  5.2. 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
  5.4. 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
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? 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? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) 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
  6.8. In diagnostic study, were details of test administration and replication sufficient? Yes
7. Were outcomes clearly defined and the measurements valid and reliable? ???
  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
  7.3. 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? ???
  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
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. 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
  8.3. 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
  8.5. 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
  8.7. 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? N/A
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes