EAL

H/A: Dietary Intake (2007)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To investigate whether closer adherence to a Mediterranean dietary pattern might be related to metabolic aspects of the HAART-induced metabolic syndrome in HIV-positive patients.

Inclusion Criteria:

HIV-infected patients
Aged at least 16 years
At least six months of cumulative exposure to any anti-retroviral regimen.

Exclusion Criteria:

None specifically mentioned.

Description of Study Protocol:

Recruitment

Consecutively enrolled patients were evaluated during a single outpatient visit to the General Clinical Research Center of Beth Israel Deaconess Medical Center; the study sample constituted approximately 10% of the entire population admitted at two ambulatory care clinics and was representative of the clinic population.

Design

Cross-sectional study

Blinding used (if applicable)

Not applicable

Intervention (if applicable)

Not applicable

Statistical Analysis

Kruskal-Wallis tests followed by post hoc Mann-Whitney analyses were used for comparisons of continuous variables among the four subgroups
Associations between MedDietScore and aspects of HAART-induced metabolic syndrome were investigated using bivariate analysis and multivariate linear regression
Variables that were not normally distributed were logarithmically transformed.

Data Collection Summary:

Timing of Measurements

Evaluated during single outpatient visit

Dependent Variables

Body composition assessed through dual-energy X-ray absorptiometry, computed tomographic findings, anthropometrics and data from interviews and questionnaires
Anthropometrics included: Weight, height and waist and hip circumferences
Blood drawn for analysis of insulin, glucose and serum lipids.

Independent Variables

Usual dietary intake was evaluated through the use of a validated self-administered food frequency questionnaire
Physical activity habits was evaluated through three multiple-choice questions on an exercise questionnaire
Mediterranean Diet Score (MedDietScore) was calculated.

Control Variables

Age
Sex
Energy intake
BMI
Waist to hip ratio
Smoking
Exercise habits
CD4 cell count
Total PI use
Total NRTI use
Total NNRTI use
Duration of illness.

Description of Actual Data Sample:

Initial N

227 patients

Attrition (final N)

227 patients

85 did not have fat redistribution, mean age 42±8 years, 10.6% female, 71.4% white
42 had fat accumulation, mean age 45±7 years, 28.6% female, 54.8% white
56 had mixed fat redistribution, mean age 46±9 years, 17.9% female, 91.1% white
35 had fat wasting, mean age 45±7 years, 2.9% female, 88.6% white.

Age

As above

Ethnicity

As above

Other relevant demographics

Anthropometrics

85 did not have fat redistribution, mean CD4 count equals 484±281 cells/mm³, mean viral load equals 6,551±20,377 copies per mL
42 had fat accumulation, mean CD4 count equals 568±350 cells/mm³, mean viral load equals 10,162±24,710 copies per mL
56 had mixed fat redistribution, mean CD4 count equals 506±315 cells/mm³, mean viral load equals 15,792±48,096 copies per mL
35 had fat wasting, mean CD4 count equals 502±263 cells/mm³, mean viral load equals 33,881±104,306 copies per mL.

Location

Boston, Massachusetts

Summary of Results:

Key Findings

Significant body composition differences were found among groups, with the fat accumulation group exhibiting significantly higher BMI, percentage of body fat, and waist-to hip-ratio compared with the non-fat-redistribution group
Fasting insulin levels and the HOMA-IR index were significantly higher in the fat accumulation and mixed fat redistribution compared with the non-fat redistribution group, whereas HDL-cholesterol levels were lower in the mixed fat redistribution and the fat wasting groups compared with the non-fat-redistribution and fat accumulation groups
In the entire study sample, a weak inverse association was found between insulin resistance, estimated using the homeostasis model assessment, and MedDietScore (standardized β= -0.15, P=0.03)
Interaction models revealed that this was largely driven by an inverse association in patients with fat redistribution (standardized β= -0.13, P=0.02)
Moreover, MedDietScore was positively correlated with HDL-cholesterol (standardized β=0.15, P=0.01) and marginally negatively associated with circulating triglyceride levels (standardized β= -0.16, P=0.13) in this group of patients.

Author Conclusion:

In conclusion, this is the first study revealing that adherence to the Mediterranean diet is favorably related to cardiovascular risk factors in a sample of HIV-positive patients with the HAART-induced metabolic syndrome studied cross-sectionally. The patients who benefited the most by higher adherence to this dietary pattern were found to be those with fat redistribution. As the Mediterranean diet has proven to be a metabolically favorable dietary pattern in the long term, its adoption may play a role in the prevention and treatment of the HAART-induced metabolic syndrome. Further clinical trials to confirm these findings and to investigate the mechanisms underlying its protective effects are needed.

Funding Source:

Government:

NIH

Industry:

Merck Research Laboratories

Pharmaceutical/Dietary Supplement Company:

Not-for-profit

American Diabetes Association

Other:

BIDMC

Reviewer Comments:

All subjects from one medical center. Authors note the following limitations:

Cross-sectional, observational design; interventions based on diet should be considered in the context of other therapeutic approaches for the metabolic syndrome, such as lipid-lowering agents, exercise and drug switching
Components of the MedDietScore are equally weighted and similarly scored from one to five, which may affect its accuracy
Insulin resistance was assessed using HOMA and not the euglycemic-hyperinsulinemic clamp, which is the criterion standard method.

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?	???
	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?	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.)	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?	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?		Yes
	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?	Yes
	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?	N/A
	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?	N/A
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	???
	7.5.	Was the measurement of effect at an appropriate level of precision?	???
	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?	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