H/A: Caloric Needs (2007)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To analyze energy and protein intake, small bowel function, body composition and REE in asymptomatic HIV-seropositive women and a control group of presumed HIV-seronegative women.
Inclusion Criteria:

Seropositive on ELISA and Western blot for antibodies against HIV-1.

Exclusion Criteria:
  • Pregnant
  • Had an AIDS diagnosis
  • Weight loss (more than 5% of usual body weight)
  • Diarrhea (bowels open more than twice a day for more than two weeks)
  • Fevers
  • Night sweats
  • Coexistent chronic systemic disease
  • Use of anabolic agents or appetite stimulants.
Description of Study Protocol:

Recruitment

Between September 1993 and September 1995, asymptomatic HIV-seropositive women were recruited from the HIV outpatients department at the Chelsea and Westminster Hospital, London. Controls were recruited from low-risk groups.

Design

Case-control study.

Intervention (if applicable)

Measurements made between cases and controls and compared.

Statistical Analysis

Comparison between groups was by one-way ANOVA and Student's T-test. Pearson's coefficient was used to assess the correlation between CD4 count and categorical variables.

Data Collection Summary:

Timing of Measurements

Subjects and controls had assessment of energy and protein intake, REE and substrate oxidation, small bowel absorption and permeability and body composition.

Dependent Variables

  • Height using stadiometer
  • Weight with digital electronic scales
  • Five-day dietary intake, energy and protein calculated
  • Small-bowel absorption and permeability
  • REE and substrate oxidation by indirect calorimetry
  • Body composition analysis by DEXA
  • Serum analysis of thyroxine, thyroid stimulating hormone, C-reactive protein, CD4 lymphocyte subset count, triglycerides and albumin.

Independent Variables

HIV seropositivity.

Description of Actual Data Sample:
  • Initial N: 10 asymptomatic HIV seropositive women, 10 heterosexual female controls
  • Attrition (final N): 10 cases, 10 controls
  • Mean age
    • Cases: 36.6±10.2 years
    • Controls: 38.0±7.8 years.
  • Ethnicity: 90% of cases and all controls were Caucasian
  • Other relevant demographics: Four were taking antiretroviral medication
  • Anthropometrics: Cases and controls well-matched for height, weight and age
  • Location: United Kingdom.
Summary of Results:

 

Cases (N=10)

Controls (N=10)

P-value

Energy Intake, kcal 1,862±343 1,447±274 P<0.05

Protein Intake

72.3±20.8

51.8±8.3

P<0.05

L-Rhamnose (Percentage Urinary Excretion)

8.0±3.1

11.3±3.1

P<0.05

D-Xylose (Percentage Urinary Excretion) 24.5±5.3 32.9±6.1 P<0.05
3-O-m-D-glucose (Percentage Urinary Excretion) 50.5±19.3 51.4±9.7 P<0.05
Lactulose (Percentage Urinary Excretion) 0.19±0.05 0.30±0.1 P<0.05
Lactulose/L-Rhamnose Ratio 0.025±0.008 0.03±0.009 P<0.05

Other Findings

  • There were no significant differences in REE, substrate oxidation and body composition
  • Energy and protein intake and small-bowel permeability were increased and sugar absorption decreased in HIV-seropositive women (all P<0.05)
  • There was no significant relationship between CD4 count or CDC status and any parameter of energy balance and no significant difference in any parameter, according to antiretroviral therapy
  • Serum biochemistry values for HIV-seropositive women were within the reference range.
Author Conclusion:
  • In conclusion, HIV per se does not cause abnormalities of metabolism or body composition in women, but is associated with mild impairment of small-bowel function
  • Elevated dietary intake and normal REE and body composition may have positive quality of life and prognostic implications for HIV-seropositive women
  • Gender differences in metabolic response to HIV infection may account in part for reported different rates of disease progression and opportunistic infection, but longitudinal studies are required to investigate this hypothesis.
Funding Source:
Reviewer Comments:
  • Small sample sizes
  • Certain measurements not done in controls
  • No power analysis done.
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? ???
  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? ???
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? 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.) Yes
  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? 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? 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? No
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? ???
  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)? N/A
  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? No
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