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SCI: Caloric and Protein Needs in Acute and Rehabilitation Phases (2007)

Citation:

Rodriguez DJ, Clevenger FW, Osler TM, Demarest GB, Fry DE. Obligatory Negative Nitrogen Balance Following Spinal Cord Injury. J Parenter Enteral Nutr 1991; 15(3): 319-322.

PubMed ID: 1907682
 
Study Design:
Case-Control Study
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
  • To test the hypothesis that negative nitrogen balance (NB) is obligatory in SCI patients.
  • To determine the profile of the metabolic response to SCI.
Inclusion Criteria:
  • Acute SCI, fewer than seven weeks postinjury
  • Controls with multi-system trauma but no spinal cord injury
Exclusion Criteria:
  • Not specified.
Description of Study Protocol:

Recruitment:  Patients admitted to Level I trauma center

Design:  Case-control study.

Blinding Used (if applicable):  not applicable

Intervention (if applicable)

  1. Total nutrition support within 72 hours of admission (based on predicted energy expenditure = Harris Benedict equation x 1.2 x 1.6) and 2g of protein per kg of ideal body weight.
  2. Subsequent changes in nutrient delivery were based on nitrogen balance.
  3. Indirect calorimetry was performed.

Statistical Analysis

Statistical analysis methods not described - descriptive statistics used.

Data Collection Summary:

Timing of Measurements

Changes in nutrient delivery were based on nitrogen balance.

Dependent Variables

  • Nitrogen balance determined through 24-hour urinary urea nitrogen collections

Independent Variables

  • Presence of SCI
  • Nutritional support:  calorie and protein intakes, types of formulas, and formula tolerances were recorded on a daily basis.

Control Variables

  • Multi-system trauma but no SCI.
Description of Actual Data Sample:

Initial N:  10 SCI patient cases (8 men, 2 women), 20 control subjects (16 men, 4 women) with multi-system trauma but no SCI

Attrition (final N):  as above

Age: Mean age of patients = 48 years (range 25 - 83 years), controls = 45 years (range 16 - 80) 

Ethnicity: Not mentioned

Other relevant demographics: 

Anthropometrics:  Cases and controls matched for time, sex, age, and injury severity score.

Location: New Mexico

Summary of Results:

Other Findings

  1. No SCI patients established positive NB during the seven-week period following injury, despite an average delivery of 2.4 g of protein/kg IBW and 120% of the PEE at the time of peak negative NB (-10.5).
  2. In six SCI patients, an average increase of 25% in delivered protein, and 12% in delivered calories over a one-week period, affected no change in average NB.
  3. Indirect calorimetry in five SCI patients showed that calorie intakes were 110% more than average measured energy expenditure.
  4. 17 of 20 control patients achieve positive NB within three weeks of admission. They required an average delivery of 2.3g of protein per kg IBW and 110% of PEE to reach positive NB.
Author Conclusion:
  • The data demonstrates the phenomenon of obligatory negative NB acutely following SCI. Aggressive attempts to achieve positive NB in these patients fail and result in overfeeding.
Funding Source:
University/Hospital: University of New Mexico
Reviewer Comments:
  • Well designed case-control study. Study period was long enough to assess the effects of nutrition support in nitrogen balance.
  • Great selection of the control group, the data is comparable.
  • Results have significant clinical and nutritional implications on SCI care.
  • Statistical analysis not described - descriptive statistics used
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.) 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? 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.) 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? 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? Yes
  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? 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? Yes
  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? No
  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? No
  8.3. Were statistics reported with levels of significance and/or confidence intervals? No
  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)? No
  8.6. Was clinical significance as well as statistical significance reported? No
  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? ???
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