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SCI: Role of the Registered Dietitian (2007)

Citation:

Szlachic Y, Adkins R, Adal T, Yee F, Bauman W, Waters RL. The effects of dietary intervention on lipid profiles in individuals with spinal cord injury. The Journal of Spinal Cord Injury. 2001; 24 (1): 26-29. [#82]

Worksheet created prior to Spring 2004 using earlier ADA research analysis template.
PubMed ID: 11587431
 
Study Design:
Non-Randomized Controlled Trial
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To evaluate the effects of a simple dietary intervention for individuals with chronic spinal cord injury and moderately elevated cholesterol.

 

Inclusion Criteria:

Spinal cord injury patients, more than two years post-injury, who underwent routine physical exam in outpatient spinal injury clinic and were examined at least one year later.

Exclusion Criteria:

Persons with no SCI and those not yet more than two years post-injury.

 

Description of Study Protocol:

Recruitment

  • Initial and follow-up lipid profiles collected as part of routine annual assessments. Those with total cholesterol of more than 200mg per dL on initial examination were referred to a staff dietitian (Group One).
  • Those with cholesterol less than 200mg per dL were Group Two.

Design

Non-randomized prospective trial with concurrent control group.

Intervention

  • Dietary consultation consisted of food intake recall with attention to amount of cholesterol and fat consumed. Intervention followed the 1996 AHA/ADA guidelines.
  • Individuals were specifically advised to limit daily fat to less than 30% and saturated fat to less than 10% of calories, limit cholesterol to less than 300mg and increase carbohydrate to 60% of calories. Subjects were seen at least twice to assess dietary compliance.

Statistical Analysis

  • Multivariate repeated-measures analysis, controlling for age and duration differences, was used to test for lipid differences between groups
  • Lipid values for Group One tended to decline, while values for Group Two tended to increase.
Data Collection Summary:

Outcomes and Other Measures

  • Lipid profiles following overnight fast at initial and at 16 months (on average); all testing was done by the same laboratory
  • Changes in total cholesterol, LDL and HDL cholesterol and triglycerides compared between groups.
Description of Actual Data Sample:
  • Initial N: (222 individuals (serial cases during two-year period); 198 men, 24 females
  • Age: 38.5±11.1; 12.8±8.3 years post-injury
  • Ethnicity: 22% Caucasian, 21% African-American, 54% Hispanic, 2% Asian and 1% other
  • Other relevant demographics: 38% complete paraplegia, 34% complete tetraplegia, 12% incomplete paraplegia and 16 incomplete tetraplegia.
Summary of Results:

 

Group 1 (N=86) was significantly older than Group 2 (N=136), with mean age 42.8 years vs. 35.7 years (F=23.6, DF=1,220, P<0.001) and had longer post-injury duration, with 15.6 years vs. 11.1 years (F+16.9, DF=1220, P<0.001). 

Total Cholesterol (mg per dL) Time One Time Two P-Value

Group One

234±31
224±31
0.001
Group Two
162±23
166±30
0.006

Group differences significance: 69% of Group One and 43% of Group Two had reductions in total cholesterol (P=0.0002).

Low Density Lipoprotein Cholesterol (mg per dL) Time One Time Two P-Value

Group One

159±28
151±28
0.004
Group Two
101±21
104±27
Non-significant

Group differences significance: 67% of Group One and 47% of Group Two had decreases in LDL-cholesterol (P=0.007).

Triglycerides (mg per dL) Time One Time Two P-Value

Group One

183±161
162±103
Non-significant
Group Two
99±59
104±71
Non-significant

Group differences significance: 60% of Group One and 45% of Group Two had declines in TG (non-significant difference).

Low Density Lipoprotein Cholesterol (mg per dL)                                                               

No significant differences, however 33% of Group One and 31% of Group Two had HDL less than 35mg per dL.

Author Conclusion:
  • SCI outpatients with mildly elevated total and LDL-cholesterol responded favorably to the dietary intervention
  • Group One had significant declines in total cholesterol and LDL-cholesterol, whereas Group Two had significant increases in total cholesterol
  • While the overall Group One mean change was not clinically significant, 17% of the group reduced total cholesterol to less than 200mg per dL and 21% reduced LDL-cholesterol to less than 135mg per dL.

 

Funding Source:
Government: US Dept. of Education
Reviewer Comments:
  • Heterogenious sample, represented by taking serial cases over two years, favors generalizability across the population of adult SCI outpatients. However, no exclusion criteria were mentioned and the number and characteristics of those not available for follow up “at least one year later” is not disclosed.
  • Another weakness of the study was that the groups were not comparable on three different levels: Group One was significantly older, had a longer post-injury duration and had high cholesterol (more than 200mg per dL) when compared to Group Two. It would have been interesting to randomize these patients to get more comparable groups. 
  • Except for this, the study appears well executed and data were appropriately analyzed. Authors' presentation of outcomes in three ways is helpful: Mean values at two points in time, significance of change over 16 months and proportion, reaching a clinically meaningful criterion.
  • The implications of the time period for follow-up and amount and timing of exposure to nutrition intervention are not addressed.
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? No
  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? No
  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? No
  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? No
  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.) 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? No
  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%.) No
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? No
  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? Yes
  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? 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? No
  6.6. Were extra or unplanned treatments described? No
  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? 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