SCI: Preventing Overweight (2007)

Citation:

Desport JC, Preux PM, Guinvarc'h S, Rousset P, Salle JY, Daviet JC, Dudognon P, Munoz M, Ritz P.  Total body water and percentage fat mass measurements using bioelectrial impedance analysis and anthropometry in spinal cord-injury patients. Clinical Nutrition 2000;19(3):185-190.

PubMed ID: 10895109
 
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:
  1. Validate bioelectrical impedance analysis (BIA) as a means to estimate total body water (TBW)
  2. Validate a skinfold measurement of percent fat mass (% FM), independent of hydration status of fat free mass (FFM).
Inclusion Criteria:
  • Partial or complete paraplegic or quadriplegic patients
  • Diagnosed at least four months previously (when energy states stabilize).
Exclusion Criteria:
  • Significant infection in preceding 15 days
  • Pressure sores
  • Pregnancy
  • Surgical intervention in preceding month
  • Cauda equina syndrome
  • Capable of walking

 

Description of Study Protocol:

Recruitment

20 successive patients with paraplegia or quadraplegia

Design

Comparison of total body water by BIA, or calculated by 3 formulas, with total body water by 18O as the reference method in subjects with SCI.  Comparison of fat mass percentage by each of the skinfolds (biceps, triceps, subscapular, suprailiac) using Siri's 3-compartment formula with a reference value for fat mass percentage using the sum of the skinfolds.

Blinding used (if applicable):  Not applicable

Intervention:  Not applicable 

Statistical Analysis

Averages of quantitative variables was compared by t-test or the Wilcoxon test.

Data Collection Summary:

Timing of Measurements

One time.  Anthropometric measurements, labeled water test and BIA initiated in AM, following overnight fast. 

Dependent Variables

  • Reference TBW calculated with information from a BIA dual frequency (50 and 100 kHz) automatic instrument (Analyco3, France) asing Vache et al V100 and V50 formulas, as well as Segal’s formula. Concordance with TBA determined by labeled water compared using the Bland-Altman procedure
  • Skinfold measures at four sites (triceps, biceps, subscapular, suprailiac) used alone to determine FM and body density (D), and their sum used to determine D. Then %FM was calculated using the three compartment Siri formula.
  • Using the Bland-Altman plot %FM obtained in the best condition (sum of skinfolds and reference TBW) was compared with simple bedside techniques (single and sum of skinfolds and TBW obtained from impedance).

Independent Variables

  • SCI

Control Variables

  • none
Description of Actual Data Sample:

Initial N: Five quadriplegic and 15 paraplegic patients, 75% males

Attrition (final N): no attrition reported

Age:  Mean 45.4 years

Ethnicity: not reported

Other relevant demographics: none

Anthropometrics: All without brain or central nervous system sequellae, not malnourished and no edema. Subscapular or suprailiac or tricep skinfold measures could not be done on eight patients due to mobility limitations or excess weight.

Location: Department of Physical Medicine and Readapation of the Regional University Hospital of Limoges, France

 

 

Summary of Results:

 TBW obtained by 4 different methods, and compared to the reference value, labeled water

Method Average TBW (L) Difference from reference value (L) P  value
Labeled water 34.15±4.87 NA NA
Vache BIA formula at 100 kHz 34.91±5.4 0.76±1.85 p=0.1
Vache BIA formula at 50 kHz 35.35±5.4 1.21±1.89 p<0.05
Analycor3 dual-frequency automatic instrument 37.47±5.71 3.32±2.53 p<0.001
Segal's formula 38.51±5.46 4.36±2.09 p<0.0001
 

Other Findings

  • Average values obtained for TBW differed significantly from the reference value (labeled water), except for the V100 formula.
  • No differences were found between the use of single or summed skinfold measures when mean percentage of fat and TBW from V100 were compared to the best condition. However, the triceps skinfold had the lowest variability on the Bland-Altmann plot compared to the reference value.

Author Conclusion:

TBW calculated from the formula using 100kHz resistance, height, and gender had acceptable concordance with labeled water results.

Each skinfold can be used for assessing %FM, but triceps skinfold, with lowest variability compared to reference values, can be used alone in clinical practice.

Funding Source:
University/Hospital: Universitary Hospital Limoges, Universitary Hospital Angers, Centre Hospitalier Universitaire Dupuytren (all France)
Reviewer Comments:

The study validates non-invasive methods for assessing body composition in SCI patients who are at least four months post-diagnosis.

Methodology and analysis are reported in detail and appear appropriate.

Not all patients were measured for all skinfolds because of difficulty with mobility for the subscapular or suprailiac skinfolds, and from the excess weight or obesity for the triceps or subscapular folds

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) ???
  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? Yes
  2.2. Were criteria applied equally to all study groups? N/A
  2.3. Were health, demographics, and other characteristics of subjects described? No
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? No
  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.) No
  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")? No
4. Was method of handling withdrawals described? Yes
  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? 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? ???
  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? ???
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? 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? N/A
  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? Yes
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? 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)? 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? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? Yes