EAL

H/A: Body Composition Measurement (2009)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To characterize the body composition of children with human immunodeficiency virus (HIV) infection, especially those with growth failure (GF), using laboratory-based methods.

Inclusion Criteria:

Age range of four years to 11 years
Positive HIV status
Patient at St. Luke's-Roosevelt Hospital Center Pediatric HIV/AIDS center between January 1994 and November 1996.

Exclusion Criteria:

Age range outside of four years to 11 years
Negative HIV status
Not taking megestrol acetate
Not taking corticosteriods
No apparent renal or cardiac disease
No known or suspected active intercurrent illnesses at the time of evaluation of body composition.

Description of Study Protocol:

Recruitment

Thirty-four pre-pubertal children with HIV infection, age four years to 11 years, were recruited from St. Luke's-Roosevelt Hospital Center Pediatric HIV/AIDS program in New York City from January 1994 through November 1996
Eighteen HIV-infected children with GF and 16 HIV-infected children with normal rates of growth were enrolled
Control subjects were 52 healthy children of similar age and ethnicity who were volunteers in an ongoing study of body composition in normal children.
- The healthy children were recruited by notices in local newspapers, at schools, in after-school activity centers and from children receiving routine health maintenance in a hospital-based clinic.

Design

Case-control study; cross-sectional data.

Statistical Analysis

The dependent variables were initially analyzed using two-factor analysis of covariance (ANCOVA) for unbalanced designs, including HIV-infected with GF, HIV-infected without GF, healthy and sex
Because there were significant interactions between the HIV/GF status and sex, these data were reanalyzed using a single-factor ANCOVA for boys and girls. Age was used as the covariate and age-adjusted means of the dependent variables are reported for each group by sex.
The level of significance was 0.05 for all statistical tests.

Data Collection Summary:

Timing of Measurements

All body composition measurements were done at the Body Composition Unit during a study visit at St. Luke's-Roosevelt Hospital Center.

Dependent Variables

Weight was measured with children wearing light clothing to the nearest 0.1kg using a beam-balance scale
Height was measured without shoes to the nearest 0.5cm using a fixed wall-mounted stadiometer
Body cell mass (BCM) by total body potassium counting
Body fat percentage by dual-energy X-ray absorptiometry
Fat mass (FM) by dual-energy X-ray absorptiometry
Fat-free mass (FFM) by dual-energy X-ray absorptiometry
FFM, FM and BCM were normalized for height to allow comparisons between groups.

Independent Variable

HIV status.

Control Variables

Age
Sex
Ethnicity.

Description of Actual Data Sample:

Initial N

34 pre-pubertal children with HIV infection
52 healthy children without HIV.

Attrition (final N)

34 HIV-infected pre-pubertal children
52 healthy children without HIV.

Age

Four years to 11 years.

Ethnicity

Not reported.

Other relevant demographics

85% of HIV-infected subjects were receiving antiretroviral medications
GF was defined as a 12-month height velocity of the fifth percentile or lower for age using standard reference norms
No significant differences were observed between the boys and girls in corresponding growth pattern groups with respect to disease stage, degree of immune suppression as measured by CD4 and CD4%, or the number of anti-retroviral drugs prescribed
None of the subjects were receiving protease inhibitors at the time of evaluation
HIV+ boys with growth failure: mean CD4 count 109.4±149.9 cells per dL
HIV+ boys without growth failure: mean CD4 count 633.0±530.6 cells per dL
HIV+ girls with growth failure: mean CD4 count 216.0±243.9 cells per dL
HIV+ girls without growth failure: mean CD4 count 596.7±382.1 cells per dL.

Anthropometrics

18 HIV-infected children had GF
16 HIV-infected children had normal rates of growth
One child acquired HIV as a result of transfusion of contaminated blood during the neonatal period
All other HIV-infected children enrolled in the study were infected as a result of perinatal transmission.

Location

St. Luke's-Roosevelt Hospital Center Pediatric HIV/AIDS program in New York City between January 1994 and November 1996.

Summary of Results:

Other Findings

Striking differences were noted in anthropometric and body composition patterns between boys and girls with HIV infection
Boys with HIV infection without GF had significantly lower weight-for-height and FFM/height ratios than the other boys
Girls with HIV infection without GF did not have significantly lower weight-for-height and FFM/height ratios
Both groups of boys with HIV infection had significantly lower FFM/height ratios compared with healthy boys
The mean BCM/height ratio was also lower in HIV-infected boys with GF compared with healthy boys
Measures of fat of the HIV-infected boys with GF did not differ from healthy control subjects, but a statistical trend suggesting decreased body fat percentage and fat mass/height ratio was observed in HIV-infected boys without GF
Mean height-for-age, weight-for-age and weight-for-height percentiles were significantly decreased in HIV-infected boys regardless of growth status as compared with healthy boys
The mean FFM/height and BCM/height ratios were decreased in HIV-infected girls with GF compared with healthy girls
Body fat percentage and fat mass/height ratio did not differ among the three groups of girls
The HIV-infected girls with GF had significantly lower mean height-for-age and weight-for-age percentiles than the HIV-infected girls without GF and the healthy girls
The mean height-for-age percentiles of the HIV-infected girls with GF did not differ from the healthy girls.

Author Conclusion:

Boys and girls with HIV-associated GF had diminished FFM and BCM
The decrease in FFM and BCM was in striking contrast to the fat compartment, which was normal
Decreased FFM was also detected in boys with HIV infection and normal growth but not in girls with HIV infection and normal growth, suggesting that HIV infection may affect boys differently than girls
The preferential decrease in FFM and BCM over fat observed in these children is similar to findings reported in adults with AIDS wasting.

Funding Source:

Government:

National Institutes of Health

University/Hospital:

St-Luke's-Roosevelt Hospital Center

Not-for-profit

Foundation associated with industry:

Reviewer Comments:

Additional studies evaluating the factors that influence growth and body composition, including the role of HIV replication on energy balance and metabolism, are required
Evaluating the effect of HIV therapies on body composition will also be important in the future.

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?		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)	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?	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.)	Yes
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	Yes
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?		???
	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?	???
	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?	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?	N/A
	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