EAL

H/A: Caloric Needs (2007)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To determine the relationship between HIV RNA load and body weight in patients with HIV infection and the impact of HAART use.

Inclusion Criteria:

Adults over 18 years of age with any stage of HIV infection
Patients with more than two study visits
Four- to nine-month intervals between study visits
Subjects with complete data on virus load, REE and HAART.

Exclusion Criteria:

Malignancies other than Kaposi's sarcoma
Women who were pregnant.

Description of Study Protocol:

Recruitment

Study participants were enrolled in Nutrition for Healthy Living study
Participants were recruited between February 1995 and January 2003 and were observed biannually.

Design

Prospective cohort study.

Statistical Analysis

Parallel univariate analyses with use of changes in body weight and BMI, predicted by HIV load
Multivariable models were based on HAART
Each potential confounder was compared with change in virus load and change in body weight.

Data Collection Summary:

Timing of Measurements

Participants were observed biannually.

Dependent Variables

Body weight change: Weight was measured by use of digital scale
Height measured by stadiometer.

Independent Variables

Viral load determined by use of Amplicor Monitor RT-PCR assay.

Control Variables

HAART defined as either two protease inhibitors, one protease inhibitor and two nucleotide reverse transcriptase inhibitors or one nonnucleotide reverse transcriptase inhibitor and two nucleotide reverse transcriptase inhibitors
Age
Sex
Education level
Race
Income level
Risk factor associated with contracting HIV infection
Use of drugs associated with weight gain
CD4 cell count measured with fluorescent monoclonal antibody-labeled cell sorter
Daily energy intake measured through three-day food diaries
REE measured by indirect calorimetry.

Description of Actual Data Sample:

Initial N: 318 participants with 1,886 study intervals; 61 were women
Attrition (final N): 318
Mean age: 40.8±7.6 years
Ethnicity: 23% African-American, 9.4% Hispanic or Latino, 63.8% white, 3.8% other
Other relevant demographics: 173 (54%) were undergoing HAART at time of enrollment
Location: Boston, MA and Providence, RI.

Summary of Results:

	No HAART (N=490) Weight Change (kg)	No HAART (N=490) P-Value	Continuous HAART (N=1,115) Weight Change (kg)	Continuous HAART (N=1,115) P-Value
Change in HIV RNA Load, Log10 Copies/ml	-0.92	0.003	0.08	0.66
HIV RNA Load at Start of Interval, Log10 Copies/ml	-0.07	0.63	-0.05	0.64
Change in CD4 Cell Count, 100 Cells/mm3	0.03	0.91	0.35	<0.001
Change in Daily REE, kcal/kg	-0.38	<0.001	-0.26	<0.001
Daily Total Energy Intake at Start of Interval, kcal/kg	0.02	0.18	0.004	0.58

Other Findings

There was a significant interaction (P=0.01) between virus load and HAART use
In the absence of HAART, each log₁₀ increase in virus load was associated with a 0.92-kg decrease in body weight (P=0.003)
During HAART, virus load was not significantly associated with weight change
During HAART, a CD4 cell count decrease of 100 cells per mm³, rather than a change in the viral load, was associated with a 0.35-kg decrease in body weight (P<0.001)
REE was independently associated with the weight change in both models (P<0.001).

Author Conclusion:

Our findings suggest that HIV-related weight loss is a function of both virological and immunologic processes. One clinical implication of this is that patients with HIV infection who are losing weight and are not taking HAART should consider starting HAART.
For patients who have detectable virus loads and are already taking HAART, changes in adherence or changes in the HAART regimen are likely to result in weight gain, if there is an accompanying increase in the CD4 cell count
For patients who have non-detectable virus loads and are already taking HAART, it is less clear from our data how to intervene
Further research is needed to understand the strong, independent effect of REE and changes in REE on weight change in all our models.

Funding Source:

Reviewer Comments:

Diverse sample population and large sample size
Two consecutive study visits used for analysis of HAART.

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.)	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.)	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?		N/A
	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?	N/A
	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?	N/A
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