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H/A: Hyperlipidemia (2009)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

The purpose of the study was to:

  • Evaluate effects of an individualized aerobic training program in reducing fat accumulation, especially visceral and lipid disorders of HIV-infected patients
  • Estimate cardiovascular heart disease (CHD) risk and to evaluate how it is altered by the training
  • Determine parameters having an influence on training results.
Inclusion Criteria:

Patients were included if:

  • They were not classified as wasted
  • They did not change their treatment in the three months before the study
  • They received neither corticosteroid, androgens, lipid-lowering or insulin-sensitizing drugs during the same period. 
Exclusion Criteria:

Patients were excluded if they:

  • Presented cardiovascular, articular, neuromuscular or respiratory disorders contraindicating exercise testing or physical training
  • Were classified as wasted
  • Changed medications within three months of study
  • Received corticosteroids, androgen, lipid-lowering or insulin drugs during the same period.
Description of Study Protocol:

Recruitment

  • All HIV-1 infected adults with lipodystrophy, either with clinical evidence of body shape changes (self-reported by the patient or confirmed by a doctor's physical examination) or dyslipidemia, who were followed in our department were proposed to participate in our study 
  • Procedure was not described.

Design

Non-randomized trial.

Intervention

Exercise: Participants were tested before and after four months of individualized light aerobic training.

Statistical Analysis

  • Paired T-tests analysis were used for differences before and after; Wilcoxon test was applied as necessary
  • A possible effect for regression to the mean (RTM) was used
  • Pearson's correlation coefficient
  • Descriptive tests, means and SD.
Data Collection Summary:

Timing of Measurements

  • Before and after training, two supervised sessions of 45 minutes duration each week.
  • Full length of the study: Four months.

Dependent Variables

  • Body composition: Weight, BMI, FFM (kg), FFM (percentage), FM (percentage and kg), VAT (cm2), SAT (cm2), TAT  (cm2) and VAT/TAT. Whole body composition measurements were obtained using tetrapolar bioelectrical impedance analysis (BIA). Total, visceral and subcutaneous adipose tissue measurements were obtained by CT scan. VAT/TAT value was calculated.
  • Fasting TG, total and HDL-cholesterol, lactate and pyruvate were analyzed
  • TC/HDL-C and TG/HDL-C ratio were calculated and used as atherogenesis indices 
  • Plasma glucose and insulin were measured from blood collected after a 12-hour overnight fast. Insulin resistance was estimated using HOMA-IR assessment calculation. 
  • 10-year relative risk for coronary heart disease (RRCHD) was calculated through the algorithm proposed by Wilson.

Independent Variables

Light aerobic exercise.

Description of Actual Data Sample:
  • Initial N: N=19 subjects 
  • Attrition (final N): 17 (12 males, five females)
  • Age: 44.2±2.3 years.

Other Relevant Demographics

  • CD4 count 514.4 60.1 cells per µL, 22.4±3.5%
  • HIV RNA 2.1±0.2 log10copies per ml 
  • Lipodystrophic history.

Anthropometrics

Height, weight, BMI, FFM, FM, VAT, TAT, SAT.

Location

France.

Summary of Results:

 

Variables

Before Training

Measures and Confidence Intervals

After Training

Measures and Confidence Intervals

Statistical Significance of Group Difference

Weight (kg)

68.6±1.7

68.4±1.8

Not Significant (NS) 

BMI (kg/m2)

 23.5±0.5

23.5±0.5

NS

FFM (kg)

 57±2

 56±2.1

NS
FFM (%) 82.4±1.5 81.2±1.5 NS
FM (kg) 11.7±0.9 12.7±0.9 NS
FM (%) 17.6±1.5 18.8±0.9 NS
TAT (cm2) 242±23.9 211.3±22.9 0.0005
VAT (cm2) 100.6±15.4 88.7±14.3 0.004
SAT (cm2) 129±20.3 122.4±16.2 NS
VAT/TAT 0.41±0.05 0.41±0.05 NS
Total Cholesterol  254±11.8  195.1±8.1 0.005
HDL-C  36.9±2.3  39.2±1.8 0.01
LDL-C  166.5±10.2  148.9±7.1 NS
TG  237±39.4  134±18 0.003
TC/HDL-C  7.22±0.53  5.76±0.3 0.0007
TG/HDL-C  3.59±0.97  1.8±0.21 0.003
Lactate (mM)  2.58±0.2  2.08±0.21 0.005
La/Pyruvate  30.3±4.5  25.6±2.6 NS
Glucose  4.86±0.18  4.84±0.17 NS
Insulin  12.1±2.4  9.2±3.1 NS
IR-HOMA  2.56±0.6  2.04±0.7 NS

 Other Findings

  • Training program resulted in significant (P<0.01) improvements of whole body aerobic (VO2max) and peripheral oxidative capacities
  • 10-year relative risk for CVD significantly decreased from 1.12±12 to 0.97±12; P=0.004, throughout the period of study
  • The correlation coefficient between pre- and post-training values ranged between 0.71 and 0.86 (P<0.001), except for TG (0.64, P<0.01)
  • Significant strong relations were found for delta Ventilatory Threshold (P=0.001), TC (P=0.002), TG (P=0.007), TC/HDL-C (P=0.0006) and TG/HDL-C (P=0.0009) and their respective baseline values. 

 

Author Conclusion:
  • The prolonged individualized aerobic training at an intensity corresponding to the ventilatory threshold followed by HIV-infected subject with fat redistribution and metabolic disorders, resulted in a significant reduction of abdominal adipose tissue by a specific decrease of VAT
  • Blood lipid profile also improved and resting blood lactate decreased during the training
  • Ratio of TG/HDL-C and TC/HDL-C are considered good indices for atherosclerosis risk in a long-term, but using algorithms proposed for uninfected people in the RR CHD calculation may bring several problems. On one hand the method does not take into account the independent effects of infection, protease inhibitor use on cardiac and vascular health. On the other hand, the extent of positive training effects on long-term cardiovascular risks could also be underestimated, because change in the way of life (diet and PA) was not considered in Wilson's algorithm.
  • Conclusion: The study demonstrated the positive effects of a light aerobic training on central adipose accumulation, lipid disorders and basal blood lactate in HIV-infected patients
  • The intervention led to a sharp reduction of several markers for cardiovascular disorder
  • The results reinforce the interest of individualized physical activity in the induction of a lifestyle modification and in the early management of infected patients for their long-term follow-up.

 

Funding Source:
Other: None reported
Reviewer Comments:
  • The study was well done in terms of methods. All outcome variables and methods for obtaining variables were described
  • Disadvantage is the small sample size (N=19). Could have done multivariate analysis; this may have helped to explain the true impact of light exercise and account for all other confounders.
  • Overall a good study examining the effects of exercise on lipodystrophic HIV patients.
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? No
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.) 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? No
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? No
  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.) No
  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? 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? 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? ???
  7.6. Were other factors accounted for (measured) that could affect outcomes? No
  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)? No
  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? No
  10.2. Was the study free from apparent conflict of interest? Yes