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CI: Best Method to Estimate RMR (2006)

Citation:

Ireton-Jones C.  Comparison of the metabolic response to burn injury in obese and nonobese patients.  J Burn Care Rehabil 1997;18(1 Pt 1):82-5. 

PubMed ID: 9063794
 
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 determine the metabolic rate of obese burned patients, the magnitude of hypermetabolism in obese burned patients by comparing estimated REE with MEE in both obese and non-obese patients, and the usefulness of an energy equation in predicting energy expenditure of obese burned patients.
Inclusion Criteria:
Obese (30% more than IBW as determined by 1959 Metropolitan Life tables) and non-obese burned patients.
Exclusion Criteria:
None specifically mentioned.
Description of Study Protocol:

Recruitment

Recruitment methods not specified.

Design

Cross-Sectional Study.

Blinding used (if applicable)

Not applicable.

Intervention (if applicable)

EE measured with indirect calorimetry and estimated with equations.

Statistical Analysis

Statistical analysis not described.

Data Collection Summary:

Timing of Measurements

Energy expenditure measured on a mean of 8th postburn day with indirect calorimetry and estimated with equations.

Dependent Variables

  • EE measured with indirect calorimetry with SensorMedics metabolic measurement cart, measured until a steady state was achieved, protocol defined elsewhere
  • EE predicted with Harris Benedict equations to assess hypermetabolism
  • EE predicted with Ireton-Jones equations for ventilated and spontaneously breathing patients

Independent Variables

  • Measured under standard conditions:  1 hour after any physical therapy of dressing change
  • Patients receiving parenteral nutrition or continuous enteral feedings were measured during feeding
  • Patients who were receiving intermittent feedings or oral diets were measured 2 hours after any oral intake
  • Standard wound care protocols, standards of care, and medications were provided

Control Variables

 

Description of Actual Data Sample:

Initial N: 15 obese (13 male, 2 female) and 15 non-obese (14 male, 1 female)

Attrition (final N):  15 obese, 15 non-obese

Age:  mean age obese = 46 +/- 17 years, non-obese = 35 +/- 14 years 

Ethnicity:  not mentioned

Other relevant demographics:  mean body weight obese = 113 +/- 12 kg, non-obese = 74 +/- 12 kg (p < 0.05)

Anthropometrics:  There were no significant differences between obese and nonobese patients in height or burn size.

Location:  Texas

 

Summary of Results:

 

  Obese (n=15) Non-obese (n=15)

Significance

MEE (kcal/day)  2936 +/- 786  2491 +/- 604  p < 0.05

HBEE (kcal/day)

 2134 +/- 281

 1708 +/- 180

 p < 0.05

IJEE (kcal/day)  2848 +/- 573  2723 +/- 489  NS
MEE/HBEE  1.38   1.46  NS

MEE/IJEE

 1.03

 0.92

 NS

Other Findings

MEE, HBEE and weight were significantly greater in the obese versus nonobese patients (p < 0.05).

The degree of hypermetabolism (MEE/HBEE) in the obese patients was not significantly different from that of the nonobese patients. 

When both groups of patients, obese and nonobese, were combined, the mean MEE was 42% greater than then mean REE.

The Ireton-Jones equations were not significantly different from the MEEs determined by indirect calorimetry in either group of burned patients, onese or nonobese.

Author Conclusion:
In conclusion, obese burned patients have an increase in metabolic rate similar to that of nonobese burned patients.  The critically ill obese patient represents a special challenge because of the complex metabolic response to injury.  The goal of nutritional care should be to provide adequate feedings that preserve the functional lean body mass.  Careful attention should be paid to these patients to avoid subjective provision of inadequate nutritional support.
Funding Source:
University/Hospital: Parkland Burn Center, University of Texas Southwestern Medical School
Reviewer Comments:

Small numbers of subjects in groups.  Inclusion/exclusion criteria and recruitment methods not well defined.  Statistical analysis not described.  IC protocol not described.

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? ???
  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? ???
  2.2. Were criteria applied equally to all study groups? ???
  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? ???
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.) 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
  3.6. 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? 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
  5.1. 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
  5.3. 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? 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? Yes
  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? 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? 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? 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? ???
  8.1. Were statistical analyses adequately described and the results reported appropriately? No
  8.2. Were correct statistical tests used and assumptions of test not violated? ???
  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)? ???
  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