EAL

H/A: Body Composition Measurement (2009)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To evaluate the effects of three different antiretroviral treatment strategies on metabolic measures and body composition in antiretroviral-naive patients diagnosed with HIV-1 infection.

Inclusion Criteria:

Participants were included if they had:

HIV-1 infection, based on ELISA (enzyme-linked immmunosorbent assay) and Western blot or measurable plasma HIV-1 RNA
Age more than or equal to 13 years old
Willing to use a barrier method of birth control if sexually active.

Exclusion Criteria:

Pregnant or breastfeeding
Prior use of protease inhibitors or non-nucleoside reverse transcriptase inhibitors
Cumulative total of more than four weeks of nucleoside reverse transcriptase inhibitor (NRTI) use or more than one week of lamivudine (3TC) use.

Description of Study Protocol:

Recruitment

Recruitment methods were not described. The Community Programs of Clinical Research on AIDS (CPCRA) initiated a multicenter metabolic study and all participants were provided with an informed consent. The protocol was approved by the institutional review board of each center that was involved. The study took place between August 19, 1999 and January, 2002. Participants were enrolled at 13 CRCPA units composed of 46 clinics and physician offices in the United States.

Design

Cross-sectional study.

Intervention (if applicable)

Three different types of antiretroviral treatment strategies.

Statistical Analysis

All performed with SAS software version eight
T-test for demographic characteristics and percentage characteristics were compared using chi square tests
Comparison of race-ethnicity and sex-specific means of the measures of body mass were made using two-way analysis of variance and the F-test
Pairwise comparisons of the adjusted race-ethnicity and sex-specific means were performed using T-test and their nominal significance probabilities
Statistical significance for the T-test were P<0.016 and for racial-ethnic difference in means significance of P<0.5.
Multivariate regression model for each body composition measure for the following variables: Age (10-year groups), race-ethnicity (white or non-white), smoking, history of intravenous drugs, sex, three measures of HIV disease and the interaction of each of the HIV disease terms with gender.

Data Collection Summary:

Timing of Measurements

Baseline and quarterly from August 19, 1999 to January 1, 2002.

Dependent Variables

Body composition/anthropometrics were measured, including: Total body fat (TBF); body cell mass (BCM); body circumferences (midarm, waist, hip and midthigh); skinfold thickness for triceps, abdomen, and midthigh (to calculate the subcutaneous fat compartments); and waist circumference and waist-to-hip ratio (WHR) to use as surrogate measures for visceral fat
BIA calculations, TBF was calculated using the Durnin-Womersley formula (DWF) by using the triceps and subscapular skinfold-thickness measurements
Body composition measurements were obtained by study nurses who had received training and certification from the same trainer (before the study and annually).

Independent Variables

Baseline assessments included: Demographic characteristics, concomitant medications, prior AIDS-defining illness, CD4+ lymphocyte counts and HIV RNA concentrations obtained prior to the study
Three different antiretroviral treatment strategies but not specified
HIV disease characteristics: CD4, stage of HIV-1 disease, HIV RNA concentrations.

Description of Actual Data Sample:

Initial N: 422 (330 males, 92 females)
Attrition (final N): Same as initial
Age: Mean age 38.4 years (male), 37.3 years (female).

Ethnicity

Non-white (percentage): Male, 66.4%; female, 96.7%
White (percentage): Male, 33.6%; female, 3.3%
Latino (percentage): Male, 10.6%; female, 8.7%
African American (percentage): Male, 53.6%; female, 84.8%.

Other Relevant Demographics

Risk factor (percentage): Men who have sex with men, 63.8
Prior intravenous drug use: Male, 14.3; female, 12.0
PCP prophylaxis (percentage): Male, 46.4; female, 45.7
Hepatitis B (percentage): N=292 (male, 7.2; female, 3.7)
Baseline HIV RNA Log10 (copies per ml): Male 5.0 (median 5.1) female 4.8 (median 4.8)
Hepatitis C (percentage): N= 328 (male, 20.4; female, 23.9)
Current cigarette smoker (percentage): Male, 45.1; female, 55.4.

Anthropometrics

The primary outcome for this study was the sex-specific and racial-ethnicity body composition; therefore, body composition data were not part of the baseline data.

Location

Multicenter.

Summary of Results:

Significant racial and ethnic difference were present for waist circumference, WHR, abdominal skinfold thickness and midarm skinfold fat area. These measurements, when adjusted for sex, were greater for the Latinos than the other groups .

Women had significantly lower regional body fat and TBF as compared to males (P<0.005).

BIA (kg): -9.54, female; -1.27, male
BMI: -4.16 (P<0.005), female; -0.84 (P=0.18), male
DWF (kg): -7.30 (P<0.005), female; -1.83 (P<0.07), male.

Males had significantly lower BCM than women (P<0.005). BCM (kg): -1.70, males (P<0.005); -1.30 (P=0.23).

For men there was a negative association between all body composition measurements and HIV RNA concentration.

Weight (-3.05kg; P>0.02), BCM (-0.92kg; P>0.02), TBF by DWF (TBF:DWF; -1.61kg; P=0.02), and suprascapular skinfold thickness (-1.40mm; P=0.04) were significant at P=0.05.

TBF:BIA (-1.42kg; P=0.08), triceps (-1.12mm; P=0.07) and suprascapular (-1.2mm; P=0.06) skinfold thicknesses, and midarm fat area (-1.96cm²; P=0.07) were significant at P=0.1.

On the other hand, eight of the 14 associations of skinfold thickness and skinfold fat area were positively associated with HIV RNA concentrations but were not statistically significant.

Effect of CD4 lymphocyte count on total and regional body composition:

The following associations were significant for women: BMI (-0.87kg; P=0.02), TBF:BIA (-1.64kg; P=0.02), suprascapular skinfold thickness (-1.5mm; P=0.01), and midarm fat area (-2.0cm²; P=0.04)
The differences between the sexes were significant for TBF:BIA (P=0.1), suprascapular skinfold thickness (P=0.01), and skinfold fat area of the midarm (P=0.06)
The overall correlation between TBF:BIA and TBF:DWF was 0.90 (P=0.0001) in men and 0.95 (P=0.0001) in women.

Author Conclusion:

The data suggests that there is an indirect effect of the viremia associated with HIV and wasting as also associated with AIDS. However, the effects of the HIV viremia and prior AIDS defining illness affect body composition differently in men and women. The authors propose that the differences are between the genders are due to the biological differences. They recommended prospective, longitudinal studies to verify these results.

Funding Source:

Government:

grants 5U0142170-1 and 5U0146362-03

Reviewer Comments:

Overall, this was well-conducted study. The authors attempted to consider variables that could have affected the analysis including age, race-ethnicity, smoking, history of intravenous drug use and gender. Attempted to be consistent with body composition measurements. As far as the literature was concerned this appears to be the first attempt to evaluate stages of HIV disease and total body composition and regional body composition.

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?	Yes
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)	N/A
	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.)	No
	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?		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?	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?	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)?	???
	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?	No
9.	Are conclusions supported by results with biases and limitations taken into consideration?		???
	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?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes