Adult Weight Management

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

Citation:

Skouroliakou M, Giannopoulou I, Kostara C, Vasilopoulou M. Comparison of predictive equations for resting metabolic rate in obese psychiatric patients taking olanzapine. Nutrition. 2009; 25(2): 188-193.

PubMed ID: 18947974
 
Study Design:
Cross-Sectional Study
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To compare the validity of four RMR equations (Harris-Benedict ABW, Harris-Benedict BW, Schofield, and Mifflin-St.Jeor) on patients with severe mental illness taking olanzapine.

Inclusion Criteria:
  • Patients with severe mental illness, taking antipsychotic medication olanzapine for minimum of six months
  • Obese (BMI higher than 30kg/m2).
Exclusion Criteria:

Patients with a medical condition known to affect RMR (such as hypertension and diabetes).

Description of Study Protocol:

Recruitment

Subjects were referred by clinical psychologists who collaborated in the five-year project.

Design

Cross-sectional study.

Blinding Used

Implied with measurements.

Intervention

Indirect calorimetry measurement of RMR.

Statistical Analysis

Pearson's correlation coefficient (r) was calculated to observe the association between the measured and predicted RMRs for each of the predictive regression equations used. Bland-Altman analysis was used to assess the accuracy of RMR prediction with each equation.

 

Data Collection Summary:

Timing of Measurements

Subjects came to the hospital for two visits.  At visit one, each was interviewed. At visit two, after no eating for 12 hours or exercise for 24 hours, they were measured and RMR was measured.

Dependent Variables 

  • RMR measured by indirect calorimetry using the Kosmed metabolic cart
  • RMR estimated by four RMR equations (Harris-Benedict ABW, Harris-Benedict BW, Schofield, and Mifflin-St.Jeor).

Independent Variables  

Patients with severe mental illness taking olanzapine.

Description of Actual Data Sample:
  • Initial N: 128 subjects (41 men, 87 women)
  • Attrition (final N): 128 subjects
  • Age: Mean age 41 years
  • Anthropometrics: Mean BMI 34.07kg/m2
  • Location: Greece.
Summary of Results:

Key Findings 

  • Significant correlations were found between the measured and predicted RMRs with all four equations (P<0.001), with the Mifflin-St. Jeor equation having the strongest correlation in men and women (R=0.712, P<0.001). 
  • For men, Mifflin-St.Jeor had the highest percent RMR prediction accuracy, with 63% of the subjects falling within ±10% of measured RMR
  • For women, the Schofield equation had the highest percent RMR prediction accuracy, with 64% of the subjects falling within ±10% of the measured RMR
  • Linear regression analysis indicated that the Mifflin-St.Jeor equation had the lowest root mean square prediction error (RMSE) and thus the best accuracy of prediction of all equations (RMSE=373.19, R=0.623, P<0.001)
  • The Bland-Altman analysis showed no significant bias in the RMR prediction using the Harris-Benedict adjusted body weight and Mifflin-St. Jeor equations (P>0.05)
  • For men and women, the Harris-Benedict current body weight and the Schofield equations had significant over-estimation error in the RMR prediction (P<0.001).
Author Conclusion:

This study suggests that Mifflin-St. Jeor and Harris-Benedict ABW equations are most appropriate means of estimating RMR of male and female patients with severe mental illness taking olanzapine. They can predict RMR with a low estimation error and low cost.

Funding Source:
Industry:
Pharmaserve Lilly, Athens, Greece
Pharmaceutical/Dietary Supplement Company:
Reviewer Comments:

Questionable validity of Kosmed metabolic cart.

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? 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? Yes
  2.2. Were criteria applied equally to all study groups? N/A
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? No
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? 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
  4.3. 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? 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? Yes
  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? 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? 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? ???
  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? N/A
  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? 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? 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