Adult Weight Management

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

Citation:
Weijs PJ, Vansant GA. Validity of predictive equations for resting energy expenditure in Belgian normal weight to morbid obese women. Clin Nutr. 2010; 29(3): 347-351. PubMed ID: 19853980
 
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 is the best alternative for indirect calorimetry in Belgian normal weight to morbidly obese women.
Inclusion Criteria:
  • Females above the age of 18 and a BMI above 28kg/m2 without any major metabolic complications
  • Control subjects were healthy women within the same age category but with a BMI less than 28kg/m2
  • Provided written informed consent.
Exclusion Criteria:
Not described.
Description of Study Protocol:
Recruitment

Subjects were recruited at the Department of Nutrition, Public Health Medicine (normal weight) and at the Obesity Clinic (University Hospital Gasthuisberg) Leuven over the past years.

Design

Diagnostic, validity or reliability study.

Blinding Used

Implied with measurements.

Statistical Analysis

  • Subject characteristics have been analysed across BMI sub-groups by ANOVA with post-hoc Bonferroni test
  • A prediction between 90% and 110% of REE measured was considered an accurate prediction, a prediction below 90% of REE measured was classified as under-prediction and a prediction above 110% of REE measured was classified as over-prediction
  • Data were analyzed using SPSS 14.0.
Data Collection Summary:

Timing of Measurements

All measurements made on the same day and compared to calculations.

Dependent Variables

  • The indirect calorimetry measurements were performed with a ventilated hood system (Acertys Healthcare NV, Aartselaar, Belgium), which was calibrated with a standard gas every day before use
  • Measurements were standardized by internal guidelines
  • Oxygen consumption and carbon dioxide production were measured and energy expenditure was calculated by the Weir formula
  • Resting energy expenditure (REE) predictive equations included:
    • Harris Benedict 1919
    • Harris Benedict 1984
    • Bernstein
    • Bernstein FFM
    • Owen
    • Owen FFM
    • Mifflin
    • Mifflin FFM
    • Livingston
    • Schofield W
    • Schofield WH
    • FAOw
    • FAOwh
    • Henry W
    • Henry WH
    • DeLorenzo
    • Siervo
    • Lazzer
    • Lazzer FFM
    • Muller
    • Muller BMI
    • Muller FFM
    • Muller FFM BMI
    • Korth
    • Korth FFM
    • Huang
    • Huang FFM
    • Johnstone FFM
    • Weijs
    • Weijs (gender specific)
    • Harris Benedict 1984 IBW
    • Harris Benedict 1984 ABW25
    • Harris Benedict 1984 ABW50.
Independent Variables

Normal weight to morbidly obese Belgian women:
  • Body weight, fat free mass (FFM) and fat mass were assessed by BIA immediately after calorimetry when subjects were lying down for at least 30 minutes and were still in the fasting state
  • None of the subjects were using any diuretics or other medication that may give a shift intra-/extra-cellular water compartments.
Description of Actual Data Sample:
  • Initial N: 536 women
  • Attrition (final N): 536 women.

Age

Mean age by BMI group:

  • 18.5kg/m2 to 25kg/m2: 39.5 years
  • 25kg/m2 to 30kg/m2: 43.1 years
  • 30kg/m2 to 35kg/m2: 41.2 years
  • 35kg/m2 to 40kg/m2: 42.1 years
  • 40kg/m2 to 45kg/m2: 41.8 years
  • 45kg/m2 to 50kg/m2: 40.3 years
  • More than 50kg/m2: 37.8 years.
Anthropometrics

Mean BMI (kg/m2) by BMI group:
  • 21.7: 18.5 to 25
  • ), 28: 25 to 30
  • 32.8: 30 to 35
  • 37.4: 35 to 40
  • 42.1: 40 to 45
  • 47.1: 45 to 50
  • 53:  More than 50.

Location

Belgium.

Summary of Results:

Key Findings

  • Most accurate and precise for the Belgian women were the Huang, Siervo, Muller (FFM), Harris Benedict (HB) and the Mifflin equation with 71%, 71%, 70%, 69% and 68% accurate predictions, respectively; bias -1.7, -0.5, +1.1, +2.2 and -1.8%, RMSE 168kcal, 170kcal, 163kcal, 167kcal and 173kcal per day, respectively
  • The equations of HB and Mifflin are most widely used in clinical practice and both provide accurate predictions across a wide range of BMI groups
  • In an already overweight group the under-predicting Mifflin equation might be preferred
  • Above BMI 45kg/m2, the Siervo equation performed best, while the FAO/WHO/UNU or Schofield equation should not be used in this extremely obese group.
Author Conclusion:
In Belgian women, the original Harris-Benedict or the Mifflin equation is a reliable tool to predict REE across a wide variety of body weight (BMI 18.5kg/m2 to 50kg/m2), estimations for the BMI range between 30kg/m2 and 40kg/m 2  should be improved.
Funding Source:
Other: Not reported
Reviewer Comments:
  • Large sample size
  • Only women were studied
  • 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")? N/A
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? 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? No
  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? No
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? 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
  7.3. 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? Yes
  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