CI: Body Weight and Outcomes: Trauma Patients (2007)

Citation:

Choban PS, Weireter LJ, Maynes C, Obesity and Increased Mortality in Blunt Trauma. The Journal of Trauma, 1991:31(9); 1253-1257.

 
Study Design:
retrospective cohort study
Class:
B - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
The study was to evaluate the problems of overweight trauma patients to identify factors that would improve care of this special group of patients.
Inclusion Criteria:
All blunt trauma patients evaluated by the trauma service and admitted to Sentara Norfolk General Hospital between January 1 and July 31, 1987.
Exclusion Criteria:

Patients less than 12 years of age were excluded.

Although 351 patients charts were evaluated, only 184 charts contained both height and weight on admission and therefore, complete data were only available for 184 charts.

Description of Study Protocol:

Recruitment Charts were reviewed for all blunt trauma patients evaluated by the trauma service and admitted to Sentara Norfolk General Hospital between January 1 and July 31, 1987.

Design retrospective chart review

Blinding used no blinding described

Intervention : none 

Statistical Analysis Data were analyzed by analysis of variance and Duncan's multiple range test.  Stepwise regression analysis was used to analyze the relative contribution of variables to overall mortality.

 

Data Collection Summary:

Timing of Measurements all measures from retrospective chart review

Dependent Variables

  • mortality - measured by death
  • injury severity (measured by Injury Severity Score (ISS))
  • length of stay (LOS) - measured in days
  • number of days on a ventilator (VD) - measured in days
  • complications ( any documented infection, atelectasis requiring more than simple intervention, posttraumatic grand mal seizures or any complications of a diagnostic or therapeutic procedure).  Events that resulted in a prolongation of stay, increased cost to patient or increased risk of poor outcome were considered complications. 

Independent Variables

Body Mass Index calculated from weight and height (weight (kg)/(height (m)2).  Using the NCHS BMI criteria (1987), average weight was defined as <27 kg/m2;  overweight as 27-31 kg/m2 and severly overweight as >31 kg/m2.  The overweight and severely overweight categories correlate approximately with 120% and 140% of ideal body weight, respectively.

 

Description of Actual Data Sample:

Initial N: 184 charts contained both height and weight on admission needed to determine Body Mass Index; 123 (67%) men and 61 (33%) women

Attrition: not applicable

Age: mean age 33.66 years with a range of 16-77 years (included pediatric patients)

Ethnicity: not described

Other relevant demographics: none

Anthropometrics BMI ranged from 16 to 46 kg/m 2 with mean BMI 25.1

Location: Sentara Norfolk General Hospital, Norfolk, Virginia

 

Summary of Results:

 

Univariate Analyses:

 

Normal Group

BMI<27 (N=140)

Overweight group

BMI=27-31) (N=25)

Severely Overweight Group  

BMI >31 (N=19)

p Value

Mortality (%)

5.0

8.0

42.1*

<0.0001

Injury Severity Score

 21.6±1.3  22.9±2.7  22.7±4.14  NS

Length of Stay (days)

 16.7±1.9  14.3±4.31  7.8±1.25  NS
Ventilator Days  4.3±0.9  3.9±1.14  3.9±1.14  NS

Complications (average patient)

 0.50

 0.48

 0.95*

 <0.0001

Age (years)  31.7±1.13  32.7±2.6  39.8±3.25  NS

 *Difference significant at p< 0.05

Stepwise Regression Analyses:

Neither age nor gender were significant variables. However, Injury severity (20% of variability of outcome) and BMI (12% of variability of outcome) were highly significant (p<0.0001) and independent determinants of outcome.

Other Findings

 In addition, the groups were subdivided into survivors and nonsurvivors.  Normal weight nonsurvivors were supported a significantly longer time (p<0.007) than the overweight or severely overweight nonsurvivors.  The clinical deterioration to demise was quite rapid in the overweight patient.  This is reflected in the shorter length of stay and in the decreased number of ventilator days (significantly longer for nonsurviror normal weight at p<0.02).

Author Conclusion:

Severely overweight patients had higher mortality and an increase in pulmonary problems.

Funding Source:
University/Hospital: Naval Hosopital Jacksonville,Sentara Norfolk General Hospital, Eastern Virginia Medical School
Reviewer Comments:
The 1987 National Center for Health Statistics for BMI are used to define weight status in this study.
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) N/A
  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) N/A
 
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) N/A
  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? 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? 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? 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