H/A: Body Composition Measurement (2009)

Citation:
 
Study Design:
Class:
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Quality Rating:
Research Purpose:

To compare measurements of body composition in HIV-infected study subjects in the current treatment era (since January 1996) to matched HIV-infected subjects studied prior to that era and also to matched normal controls. 

Inclusion Criteria:

Participated in a body composition study performed in the Body Composition Unit at St. Luke's-Roosevelt Hospital Center from 1984 to current time. 

Exclusion Criteria:
  • Not a subject enrolled in a body composition study at St. Luke's-Roosevelt Hospital Center from 1984 to 1998
  • If non-HIV-infected, subject was not able to be matched to an infected subject based upon gender, age, weight and height.
Description of Study Protocol:

Recruitment

  • Subjects who underwent body composition studies at St. Luke's-Roosevelt Hospital Center from 1984 through the time of publication
  • Subjects included both HIV-infected and non-infected status
  • Subjects were of both genders and of varying ages and racial origins
  • Matched controls were chosen from a database of body composition results from 1,451 healthy adults and 430 HIV-infected subjects studied since 1984.

Design

Retrospective case-control study 

Blinding used 

Not applicable

Intervention

Not applicable

Statistical Analysis

  • Differences in body composition measures between groups were analyzed by one-way analysis of variance with pairwise comparisons made using the method of Scheffe
  • P value of <0.05 was determined to be statistically significant
  • To evaluate for the independent effects of study group (current HIV, previous HIV and  control) on fat distribution, multiple regression analyses were performed using the anthropometric result as the independent variables and body fat content, gender, race, age and group (current, past and control) as the independent variables. 
Data Collection Summary:

Timing of Measurements

  • Study was retrospective analysis of the results of the body composition studies, performed in the St. Luke's-Roosevelt Hospital Center, on both HIV-infected subjects and healthy adults of both genders and varying ages and racial origins since 1984
  • The current HIV group are the 96 subjects (77 men and 19 women) studied since January 1996.

Dependent Variables

  • Total body potassium (TBK) was measured using a 4-[pi] whole-body counter over nine minutes with the results adjusted for body size
  • Results of potassium measurement in mEq were converted to kilograms of body cell mass by multiplying by 0.00833
  • Anthropometric measurements included triceps, biceps, subscapular, upper iliac and upper abdominal skin folds, waist, hip circumference and were performed as described in the Airlie Consensus Report
  • Weight was measured to the nearest 0.1kg (Weight Toniz, New York, New York, USA).

Independent Variables

  • Body fat content
  • Group (current HIV, previous HIV and control).

Control Variables

  • Height
  • Age
  • Gender
  • Race.
Description of Actual Data Sample:

Initial N

  • Current HIV Group: 96 HIV-infected subjects (77 men and 19 women) of varying ages
  • Control group subjects were chosen from a database of body composition results from 1,451 healthy adults and 430 HIV-infected subjects studied since 1984.

Attrition (final N)

As above

Age

  • Current HIV Group 41.9±7.2 years
  • Previous HIV Group 40.1±7.9 years
  • Control Group 42.8±9.5 years.

Ethnicity

Not disclosed

Other relevant demographics

Current HIV Group: 51 received combination therapies including PIs, 25 received other ARV therapies and 20 did not receive any ARV therapies.

Anthropometrics

 All current HIV subjects were matched by gender, race, age (less than five years) and height (less than 10cm).

Location

St. Luke's-Roosevelt Hospital Center, New York City, New York

 

Summary of Results:

Findings

  • Heights and ages were similar in all groups as expected from the matching procedure
  • Body weights differed significantly among the groups
  • Current HIV male and female subjects weighed more than the previous HIV subjects but less than controls 
  • Current HIV male subjects weighed more (P=0.025) and had more body cell mass than previous HIV male subjects, but less than controls (P<0.001)
  • In women, the between-group differences in fat were greater than the differences in body cell mass
  • Current HIV male subjects had more body cell mass, fat-free mass and fat than previous HIV male subjects
  • Body cell mass, fat-free mass and fat all were less in both current and previous HIV subjects than in male controls (P<0.001)
  • Current female HIV subjects had less body cell mass but more fat-free mass and fat than previous HIV females, although the differences did not reach statistical significance
  • Both female HIV groups had less body cell mass, fat-free mass and fat than female controls (P<0.001)
  • Most of the difference in weight between current and previous HIV men was fat-free mass, whereas most of the weight difference in women was fat 
  • Waist circumference was significantly greater in current than in previous HIV subjects, whereas upper abdominal skin fold, hip circumference, visceral tissue area (VTA) and subcutaneous tissue area (STA) were not different in these groups 
  • The average VTA results were similar in the HIV and control groups, whereas waist circumference, hip circumference and STA all were lower in both HIV groups than in the controls (P<0.001)
  • In current HIV subjects, body fat distribution was significantly associated with log plasma HIV RNA content but not with anti-retroviral or protease inhibitor usage, nor with CD4 and lymphocyte counts.
Author Conclusion:
  • Alterations of body composition are present in HIV-infected men and women from both the current treatment era as well as the past
  • Alterations in body fat distribution also are present in both current and previous HIV-infected subjects
  • These alterations are related to HIV viral burden rather than specific ARV therapy and might be a manifestation of chronic hypercortisolism
  • Further studies of HIV-infected subjects with altered body fat distribution including studies employing more sophisticated measures, such as computed tomographic (CT) scanning or MR, are required to determine whether its presence is associated with adverse consequences and whether these changes are reversible.
  • The results of this study do not rule out a direct effect of protease inhibitor (PI) therapy on body fat distribution.
Funding Source:
Government: National Institutes of Health Grant AI 21414, DK 42618, and DK 37352
University/Hospital: St-Luke's-Roosevelt Hospital Center
Reviewer Comments:

It is possible that a larger study group of subjects observed for longer intervals with PI therapy would uncover a specific effect of these drugs on body fat distribution.

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) N/A
  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) N/A
 
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? Yes
  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? ???
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.) ???
  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.) ???
  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%.) No
  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? 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.) 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? 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