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H/A: Caloric Needs (2007)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To ascertain the relationships between resting energy expenditure, HIV RNA in plasma and highly active antiretroviral therapy.
Inclusion Criteria:

HIV-seropositive men and women enrolled in a longitudinal study (Nutrition for Life) that began in February 1995.

Exclusion Criteria:
None specifically mentioned.
Description of Study Protocol:

Recruitment

HIV-seropositive men and women enrolled in a longitudinal study (Nutrition for Life) that began in February 1995.

Design

Cross-sectional analysis of data from a large cohort study.

Statistical Analysis

  • Comparisons between persons taking and not taking HAART were performed using Fisher's exact test (for clinical stage) and Wilcoxon rank-sum test (CD4 count, viral RNA and physical functioning). Medians and interquartile ranges are shown for continuous variables.
  • All models of REE were adjusted for FFM and age. When included, CD4 lymphocyte counts, age and FFM were used on a linear scale.
Data Collection Summary:

Timing of Measurements

  • HIV RNA in plasma, REE, fat-free mass and medication regimens assessed at 530 visits among 372 participants
  • Assessments were done every six months.

Dependent Variables

  • HIV RNA in plasma, measured with Roche Amplicor Monitor reverse transcriptase polymerase chain reaction
  • Measurement of REE with indirect calorimetry.

Independent Variables

HIV seropositivity.

Control Variables

  • Fat free mass assessed by bioelectrical impedance and three site skinfolds 
  • Age
  • CD4 cell count assessed using monoclonal antibody and fluorescence-activated cell sorting analysis 
  • HAART use (either two protease inhibitors, two nucleoside reverse transcriptase inhibitors with one protease inhibitor, or two nucleoside reverse transcriptase inhibitors with one non-nucleoside reverse transcriptase inhibitors).
Description of Actual Data Sample:
  • Initial N: 372 participants from cohort
  • Attrition (final N): 372 subjects; 324 men, 48 women
  • Mean age
    • Men: 39 years
    • Women: 35 years.
  • Ethnicity
    • Men: 74% white, 15% African-American, 5% Latino, 6% other
    • Women: 42% white, 40% African-American, 10% Latino, 8% other 
  • Location: United States.
Summary of Results:

 

Not Using HAART (N=250)

Using HAART (N=122)

P-value
Clinical Stage A (Asymptomatic) 30% 17%

--

Clinical Stage B (Symptomatic Without an AIDS-Defining Illness)

30%

26.2%

--

Clinical Stage C (With an AIDS-Defining Illness)

40.2%

56.6%

0.0006
CD4 (x106 cells/ml), Median (IQR) 319 (130-500) 296 (166-399) 0.18
HIV RNA (log10 copies/ml), Median (IQR) 4.3 (3.7-5.0) 3.0 (2.3-6.2) 0.0001
Physical Functioning, Median (IQR) 75 (58-100) 88 (63-100) 0.43

Other Findings

  • HIV RNA in plasma was directly correlated with REE
  • Mean REE of men was 8,292±1,192kJ per day, of women was 6,807±1,109kJ per day
  • After adjustment for fat-free mass, age, CD4 cell count and HAART use, there was an increase in REE of 90kJ per day per log10 copies per ml increase in HIV RNA (95% confidence interval 16-164, P=0.02)
  • HAART use had an independent effect on REE
  • In patients reporting HAART use, adjusted REE was 339kJ per day higher than in those not reporting HAART use (95% confidence interval 177-501, P=0.0001).
Author Conclusion:
In conclusion, these findings suggest that HAART increases REE, independent of its effect on HIV RNA. This intriguing metabolic effect of the relatively new antiretroviral treatment regimens deserves further study, particularly longitudinal analyses of REE before and after starting such combination regimens. These findings stress the importance of understanding the mechanisms by which HAART increases REE, especially in order to permit targeted intervention studies for restoring FFM, strength, activity level and well-being in persons taking HAART to control HIV infection.
Funding Source:
Reviewer Comments:
  • Authors note that the effect of physical activity was not explored in this analysis
  • Authors also note that there were too few repeat visits in individuals before and after starting HAART to estimate changes from these drugs, as well as the fact that persons who received HAART early may have had more advanced illness and higher viral load prior to treatment, leading to the possibility of confounding by prior disease stage.
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? No
  2.2. Were criteria applied equally to all study groups? ???
  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.) ???
  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? ???
  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? No
  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? ???
  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)? ???
  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