EAL

H/A: Caloric Needs (2007)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To assess whether change in weight, lean tissue or skeletal muscle affects progression in AIDS
To assess prospectively the effects of recognized alterations in nutrition and metabolism in asymptomatic HIV-seropositive men on disease progression
To examine prospectively changes in nutrition and metabolism on AIDS-defining diagnosis.

Inclusion Criteria:

Seropositive for HIV on ELISA and confirmatory test
CDC status recorded for all subjects.

Exclusion Criteria:

AIDS diagnosis
Weight loss (greater than 5% usual body weight in last year)
Diarrhea (bowels open more than three times a day for greater than two weeks)
More than three episodes of fever or night sweats in the last year
History of IV drug use
Coexistent chronic systemic disease
Any use of anabolic agents or appetite stimulants.

Description of Study Protocol:

Recruitment

HIV-seropositive men recruited and prospectively examined at three-month intervals between April 1993 and September 1995.

Design

Prospective cohort.

Statistical Analysis

Measures compared to baseline using non-parametric Wilcoxon test and parametric paired T-test. Time-fixed and time-dependent Cox's proportional hazard models were fitted to calculate risks of developing a first AIDS diagnosis, weight loss or death.

Data Collection Summary:

Timing of Measurements

HIV-seropositive men recruited and prospectively examined at three-month intervals between April 1993 and September 1995.

Dependent Variables

Height and weight
Metabolism, measured using indirect calorimetry
Body composition through DEXA
Peripheral blood CD4 lymphocyte subset count, measured with flow cytometer
Measures of small bowel absorption and permeability
Urine excretion of simple sugars
Risk of developing a first AIDS diagnosis, weight loss or death.

Independent Variables

HIV infection.

Description of Actual Data Sample:

Initial N: 104 asymptomatic HIV-seropositive men
Attrition (final N)

104, 31 developed AIDS during two-and-a-half years
Only 26 of 31 were assessed
Two refused and three had an AIDS diagnosis away from the recruitment center.

Age: Median age at enrollment was 35.9 years for asymptomatic individuals; 37.4 years for those developing AIDS
Ethnicity: Not mentioned
Location: United Kingdom.

Summary of Results:

Change from Baseline	Relative Hazards of a First AIDS Diagnosis Adjusted for CD4 Count (95% Confidence Interval)	P-Value
Body Weight (per 1-kg Change)	1.16 (0.98-1.37)	0.08
Basal Metabolic Index (per 1-Unit Change)	1.57 (0.93-2.67)	0.09
Fat Mass (per 1-kg Change)	1.06 (0.81-1.38)	0.68
Fat-Free Mass (per 1-kg Change)	1.08 (0.82-1.42)	0.58
Appendicular Muscle Mass (per 1-kg Change)	1.27 (0.89-1.8)	0.18

Other Findings

During the study period, 31 subjects had a first AIDS diagnosis; of them 26 were fully assessed
Changes in nutrition and metabolism do not affect disease progression in asymptomatic HIV infection
Subjects with a reduction in body weight, BMI, fat mass, FFM, appendicular muscle mass and carbohydrate oxidation tend to have a higher risk of progression to AIDS-defining diagnosis, independent of CD4 count
There is a significant decrease in all body tissue compartments, a decrease in excretion of urinary sugars and significant increase in resting energy expenditure and fat oxidation associated with a first AIDS diagnosis
Patients who had a reduction in weight or BMI tended to have a higher risk of developing AIDS over the following few years: Relative hazard 1.16 (95% confidence interval 0.98-1.37, P=0.08) for a 1kg reduction in weight and 1.57 (95% confidence interval 0.93-2.67, P=0.09) per one unit reduction in BMI.

Author Conclusion:

An AIDS-defining diagnosis was associated with a cachectic response and loss of all body compartments, especially lean tissue, with an increased REE and fat oxidation. These disturbances in energy balance are exacerbated by decreased absorption of simple sugars, perhaps pre-disposing subjects with a first AIDS diagnosis to weight loss. Therefore, we believe that nutritional counseling and therapies should be instituted promptly at AIDS diagnosis, rather than managing established wasting that may be more resistant to treatment.

Funding Source:

Reviewer Comments:

Only 26 of 31 of the subjects developing AIDS were assessed.

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?	N/A
	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?		???
	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?	N/A
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	N/A
	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?	???
	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?		???
	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?	No
	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?	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?	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