H/A: Body Composition Measurement (2009)

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

To compare fat distribution as assessed by self-report, physical examination and MRI in HIV-infected and control women.  Also, to assess the relationship of fat distribution across peripheral and central body regions with antiretroviral therapy in HIV-infected women.

Inclusion Criteria:

Comparing HIV-infected Women to Controls

  • HIV-infected women enrolled in FRAM (Fat Redistribution and Metabolic Changes in HIV Infection), aged 33 to 45 years
  • Control subjects were recruited from CARDIA (Coronary Artery Risk Development in Young Adults) study, a community-based sample of 18- to 30-year-old Caucasian and African-American men and women for a longitudinal study of cardiovascular risk factors.

HIV-associated Factors Including Antiretroviral Therapy in HIV-infected Women

HIV-infected women between the ages of 19 and 70 years.

Exclusion Criteria:
  • Subjects less than 18 years of age
  • Factors that would present problems imaging: Weight more than 136kg, height more than 6'5", metal in body and claustrophobia
  • Opportunistic infection or malignancy within the same or previous calendar month as the examination.
Description of Study Protocol:

Recruitment

  • HIV-infected women enrolled in FRAM (Fat Redistribution and Metabolic Changes in HIV Infection)
  • Control subjects enrolled in CARDIA (Coronary Artery Risk Development in Young Adults).

Design

Case-control study.

Statistical Analysis

  • P-values were calculated by Fisher exact test
  • Numerical values were compared by Mann-Whitney test 
  • Associations between variables quantified by odds ratios
  • Multivariate analysis to determine whether factors unrelated to HIV infection and its therapies could account for differences.
Data Collection Summary:

Timing of Measurements

Measurement and questionnaires compared between cases and controls.

Dependent Variables

  • Change in body fat: Self-administered questionnaire
  • Body composition: MRI, height, weight 
  • Use of antiretroviral medications Medical record review.

Independent Variables

  • HIV-infection or controls
  • CD4 cell counts and HIV RNA levels: Measured in HIV-infected women.

 

 

Description of Actual Data Sample:
  • Initial N: 350 women (comparing HIV-infected women to controls); 338 women (analyses of HIV-associated factors including antiretroviral therapy in HIV-infected women in HIV-infected women)
  • Attrition (final N): 325 women (comparing HIV-infected women to controls)
  • Age:
    • HIV-infected women: 39 years of age
    • Control: 42 years of age 
  • Ethnicity:
    • HIV-Infected women: 32% Caucasian, 56% African-American, 10% Hispanic
    • Control: 49% Caucasian, 51% African-American
  • Anthropometrics: Weight in kg for infected group was 71.7kg; for control group, 75.1kg (P<0.017). BMI was similar for both groups.
  • Location: Not stated (this was part of a larger FRAM study and mentioned that recruitment and data collection procedures for the entire cohort were described elsewhere).

 

Summary of Results:

 

Variables

HIV-infected Group

Control Group

 

Statistical Significance of Group Difference

Peripheral lipoatrophy in at least one site

28%

 

4%

 

P<0.001

Presence of peripheral lipohypertrophy

35%

62%

P<0.001

Other Findings

More HIV-infected women than controls reported fat loss in peripheral sites (cheeks, face, arms, buttocks and legs) (P<0.001).

Prevelance of clinical central lipoatrophy was low for both HIV and control groups (6% vs. 3%). 

Peripheral lipoatrophy was more frequent in HIV-infected women than controls (28% vs. 4%, P<0.001).

The prevalance of central lipohypertrophy in at least one site was very high for both groups (62% HIV-infected, 63% control).

Among HIV-infected women, the presence of central lipohypertrophy was associated with reduced likelihood of peripheral lipoatrophy (OR 0.39; 95% CI 0.20 to 0.75, P=0.006) than those without central lipohypertrophy.

On MRI, HIV-infected women with clinical peripheral lipoatrophy had less subcutaneous adipose tissue in peripheral and central sites and less visceral adipose tissue than HIV-infected women without peripheral lipoatrophy.  

Compared with controls, HIV-infected women had less subcutaneous adipose tissue in the legs, regardless of the presence or absence of lipoatrophy.

However, those without lipoatrophy had more visceral adipose  tissue and upper trunk subcutaneous adipose tissue than controls.  

Antiretroviral therapies: Stavudine was associated with less leg subcutaneous adipose tissue but not associated with visceral adipose tissue.

HAART (highly active antiretroviral therapy) was associated with more ventral abdominal tissue.

Author Conclusion:

Peripheral lipoatrophy occurs commonly in HIV-infected women but is not associated with reciprocally increased ventral abdominal tissue or trunk fat.

Funding Source:
University/Hospital: Part of a larger study: Study of Fat Redistribution and Metabolic Change in HIV Infections (FRAM). University of California, San Fransisco, Veterans Affairs Medical Center, Infectious Disease Section, San Fransisco, CA.
Reviewer Comments:

Controls were not selected from women with similar risk behaviors. Control group was significantly older (P<0.001) and significantly more Caucasian (P=0.002) than HIV-infected group.

Mentioned 350 women initially but demographic data only includes 325 women.

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? ???
  2.2. Were criteria applied equally to all study groups? No
  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? 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? 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.) ???
  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? ???
  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? ???
  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? N/A
  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? 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? N/A
  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? 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