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COPD: Effectiveness of Therapies (2007-2008)

Citation:
Daga MK, Chhabra R, Sharma B, Mishra TK. Effects of exogenous vitamin E supplementation on the levels of oxidants and antioxidants in chronic obstructive pulmonary disease.  Journal of Bioscience 2003, 28:7-11. PubMed ID: 12682418
 
Study Design:
Randomized controlled trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
The purpose of the current study was to compare the oxidation product (MDA) and antioxidant superoxide dismutase (SOD) levels in COPD and healthy nonsmokers.
Inclusion Criteria:
  • COPD diagnosis by FEV1 < 80%
  • age over 35 years
Exclusion Criteria:
  • under 35 years old
  • on vitamin supplementation of > 4 weeks
  • with systemic disease
  • FEV1 < 80% with reversibility > 15%
  • in acute exacerbation
Description of Study Protocol:

Recruitment

Methods not mentioned. 

Design

Randomized controlled trial.

Blinding used (if applicable)

Double blind.

Intervention (if applicable)

15 subjects randomly assigned to receive exogenous vitamin E (400 IU per day) supplementation for 12 weeks or continue on standard supportive treatment.

Statistical Analysis

Statistical analyses included  t tests and Pearson's coefficient correlations.

Data Collection Summary:

Timing of Measurements

Baseline and after 12 weeks supplementation.

Dependent Variables

  • MDA level estimations by thiobarbituric acid (TBA) reaction and spectrophotometer (Asakawa and Matsushita, 1980)
  • alpha tocopherol levels by fluorometer units vs concentration of tocopherol standards (Hansen and Warwick 1969)
  • erythrocyte superoxide dismutase (SOD) levels estimate on baisi of inhibition of pyrogallol autoxidation by SOD (Markland and Markland, 1974 and Nandi and Chatterji 1988)
  • forced expiratory volume in first second (FEV1)
  • FEV1/FVC
  • peak expiratory flow rate (PEFR)

Independent Variables

  • Assigned to receive exogenous vitamin E (400 IU per day) supplementation for 12 weeks or continue on standard supportive treatment

Control Variables

 none

Description of Actual Data Sample:

Initial N: 30 included in the study, 24 male, 6 female, 20 nonsmoking controls matched for age and sex

Attrition (final N):

  • patients n = 30
  • controls n = 20

Age: over 35 years

Ethnicity: not clear

Other relevant demographics: 80% of patients were male

Anthropometrics:  controls were age and sex matched

Location:  New Delhi, India

Summary of Results:

Other Findings

Mean MDA level in patients was 29.7% higher than controls at baseline (5.91 + 1.23 nmol/ml vs 4.55 + 1.57 nmol/ml, p=0.001). 

Mean plasma alpha-tocopherol level in patients (7.09 + 2.14 micrograms per ml)was 28.67% lower than controls (9.94 + 2.01 micrograms per ml, p < 0.001).

Mean SOD level in patients  was 30.9% lower than controls (1692 + 259 units/gm Hb vs 2451 + 131 units/gHb, p<0.001).  At baseline, smokers with COPD had higher MDA levels but lower antioidant (SOD and tocopherol ) levels than healthy controls.

Twelve weeks of vitamin E supplementation produced 42.8% reduction in mean MDA level (3.37 + 0.81 nmaol/ml vs 5.91 + 1.43 nmol/ml, p <0/001)  No significant change in mean plasma alpha-tocopherol levels and mean SOD level was observed after 12 weks of vitamin E supplementation.

No significant improvement in FEV1, FEV1/FVC and PEFR was observed after 12 weeks of vitamin E supplementation.

 

 

 

Author Conclusion:
Our study shows that initially the plasma lipid-peroxidation products (MDA levels) are high, and anti-lipid-peroxidation products (MDA levels) are high and andti-oxidants (alpha tocopherol and SOD) are low in patients with COPD.  Exogenous supplementation of vitamin E does not have any significant effect on the spirometric measurements though it brings down the level of MDA suggesting attenuation of oxidative damage.
Funding Source:
University/Hospital: Maulana Azad Medical College
Reviewer Comments:
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? ???
  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? ???
  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? ???
3. Were study groups comparable? ???
  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? ???
  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.) 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? 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? 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? ???
  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? ???
  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? ???
  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? ???
  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? ???
  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? No
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? No
10. Is bias due to study's funding or sponsorship unlikely? ???
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? ???