EAL

H/A: Body Composition Measurement (2009)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To investigate the variability of dual-energy X-ray absorptiometry (DEXA) scans analysis performed at local sites compared to central analysis in a multicenter clinical trial.

Inclusion Criteria:

HIV-infected patients with physician-documented lipodystrophy
HIV RNA load less than 400 copies per ml
Stable on a protease-inhibitor (PI)-containing therapy
No prior abacavir, nonnucleoside reverse transcriptase inhibitor, or adefovir therapy.

Exclusion Criteria:

Active AIDS-defining condition
Pregnant
Ongoing substance abuse.

Description of Study Protocol:

Recruitment

Data were collated from adult patients enrolled in the PIILR study conducted by the National Centre in HIV Epidemiology and Clinical Research.

Design

The PIILR study was a multicenter randomized clinical trial.

Intervention

Total and regional body composition were quantified at screening and at weeks 12 and 24 by DEXA
Scans were performed and analyzed at referral centers and reanalyzed at central location.

Statistical Analysis

Mean change from baseline was calculated for each DEXA scan result for the continue and switch arms for both central and local readings
The continue and switch arms were compared using a two-tailed T-test from which an estimate of the common standard deviation was obtained
The variability in the local and central DEXA analyses was compared by calculating the ratio of local standard deviation to central standard deviation.

Data Collection Summary:

Timing of Measurements

Total and regional body composition were quantified at screening and at weeks 12 and 24
Scans were performed and analyzed at referral centers and reanalyzed at a central location.

Dependent Variables

Total and regional body composition were measured with Lunar DEXA scans.

Independent Variables

HIV infection
Documented lipodystrophy.

Description of Actual Data Sample:

Initial N: 80 patients
Attrition (final N): 73 patients completed the 24-week study
Anthropometrics: Differences between groups not described
Location: Australia.

Summary of Results:

Measure	Local Reading: Mean Change from Baseline Continue (N=30)	Local Reading: Mean Change from Baseline Switch (N=43)	P-value	Central Reading: Mean Change from Baseline Continue (N=30)	Central Reading: Mean Change from Baseline Switch (N=43)	P-value
Body fat, kg	-0.26	-1.42	0.028	-0.47	-1.70	0.007
Body fat, %	-0.06	-1.43	0.018	-0.55	-1.82	0.017
Trunk fat, kg	0.15	-0.60	0.034	-0.17	-1.05	0.002
Trunk fat, %	0.14	-1.08	0.106	-0.58	-2.00	0.031
Abdominal fat, kg	-0.01	-0.15	0.016	-0.02	-0.17	0.005
Lean body mass, kg	0.03	-1.33	0.009	-0.30	-1.08	0.004

Other Findings

Greater variation in the locally analyzed results than in the centrally reanalyzed data was noted, with arm, leg and combined limb fat being most divergent between the local and centralized assessments (ratio of local to central standard deviation was 1.28, 1.31 and 1.35, respectively).

The magnitude of this variance was enough to alter statistically relevant differences between study populations.

Author Conclusion:

The variation in data from DEXA scans analyzed by multiple sites and multiple operators is reduced when scans are reanalyzed at a single center by a single operator. Quality assurance is an important issue in the use of DEXA scans to determine body fat composition in multicenter research studies. A central quality assurance site should be incorporated to reduce variability in results.

Funding Source:

Government:

Commonwealth Department of Health and Ageing through the Australian National Council on HIV, Hepatitis and Related Diseases

Reviewer Comments:

Did not describe PIILR study in detail or study subjects. Differences between groups not statistically analyzed.

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?	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)	No
	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?	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?	???
	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?	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?	Yes
	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?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	???
	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