CI: Best Method to Estimate RMR (2010)
Campbell CG, Zander E, Thorland W. Predicted vs measured energy expenditure in critically ill, underweight patients. Nutr Clin Pract 2005;20(2):276-80.PubMed ID: 16207663
Critically ill patients admitted to a tertiary-care hospital in the Pacific Northwest from 1992 - 2003.
Cross-Sectional Study, Retrospective Analysis.
Blinding used (if applicable)
Intervention (if applicable)
A comparison of 4 energy-prediction equations against MREE determined via indirect calorimetry.
Differences between MREE and the prediction equations were tested by repeated-measures ANOVA with post hoc pairwise comparisons using Bonferroni adjustment. Data are presented as mean +/- SD. Regression analysis was conducted between the predicted and MREE values. The mean prediction error (MREE - predicted energy needs) was calculated to evaluate the tendency to over- or underestimate energy needs. Level of significance set at p < 0.05.
Timing of Measurements
Retrospective analysis of indirect calorimetry measurements compared with equations.
- RMR measured with indirect calorimetry using DeltaTrac, 3-4 carts used over study period, calibrated according to manufacturer's instructions, performed by trained respiratory therapists, all patients in steady state for >10 minutes, and had stable R value of <1.0
- RMR estimated with Harris-Benedict equation using both current weight and IBW for patients <90% IBW, and adjusted body weight ([current body weight + IBW]/2) for patients <85% IBW
- RMR estimated with Ireton-Jones equation for all mechanically ventilated patients (n=37)
- All patients received nutrition support while indirect calorimetry performed
Initial N: 42 critically ill male patients, 37 mechanically ventilated
Attrition (final N): 42 males
Age: 59.5 +/- 17.3 years
Ethnicity: Not mentioned
Other relevant demographics: Severely underweight, mean weight 57.97 +/- 8.31 kg, 77.1 +/- 9.7% IBW as determined by Hamwi, mean BMI 18.4 +/- 2.5
|MREE (kcals)||I-J (kcals)||HB(CBW)||HB (IBW)||HB (ABW)|
|Sample Size||n = 42||n = 37||n=42||n = 42||n = 31|
The Harris-Benedict formula using IBW, current weight and adjusted body weight was significantly different (p < 0.05) than MREE.
The Ireton-Jones equation was not significantly different (p > 0.05) from MREE but tended to overestimate energy needs (109.3% +/- 16.8% MREE).
Conversely, using the current weight or the IBW in the Harris-Benedict equation underestimated the patient's energy needs (77.0% +/- 11.6% MREE and 90.9% +/- 16.1% MREE, respectively).
For patients <85% IBW, use of the adjusted body weight in the Harris-Benedict equation represented 84.2% +/- 13.9% MREE.
The average caloric need was 31.2 +/- 6.0 kcal/kg current body weight.
The mean prediction error for all subjects was 110.1 for the Ireton-Jones equation, -440.7 for Harris-Benedict with current body weight, and -204.7 kcals/day for Harris-Benedict with IBW.
All equations were significantly correlated (p < 0.05) with MREE (r = 0.61 for Ireton-Jones, r = 0.67 for Harris-Benedict with current body weight, and r = 0.53 for Harris-Benedict with IBW).
For patients <85% IBW, the mean prediction error was -314.8 kcal/day for the Harris-Benedict equation with adjusted body weight, which was significantly correlated with MREE (r = 0.57, p < 0.05).
|University/Hospital:||Montana State University, Sacred Heart Medical Center|
Quality Criteria Checklist: Primary Research
|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|
|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?||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?||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?||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?||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?||???|
|7.7.||Were the measurements conducted consistently across groups?||???|
|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)?||N/A|
|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|