H/A: Diarrhea/Malabsorption (2009)

Citation:
 
Study Design:
Class:
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Quality Rating:
Research Purpose:

To compare two enteral formulas, differing only in fat source, for product acceptance, tolerance and effect on fat malabsorption and nutritional status in subjects with AIDS.

Inclusion Criteria:
  • AIDS
  • At least 10% below IBW
  • Had documented weight loss of 10% of usual body weight during the previous six months
  • Fat malabsorption
  • No subject had a life expectancy of less than four weeks nor a Karnofsky performance status scale score of less than 50/100.
Exclusion Criteria:
  • No subjects had physical or functional intolerance to food intake
  • Severe, uncontrolled diarrhea
  • Clinical or radiologic evidence of ascites or pleural effusions
  • Recent hospitalization because of exacerbation of illness and attendant weight loss.
Description of Study Protocol:

Recruitment

Recruited from infectious disease clinics at the University of Alabama at Birmingham.

Design

Randomized clinical trial.

Blinding used

Double blind.

Intervention

15-day trial: three-day workup period during which controlled solid food containing 100g of fat was consumed to document fat malabsorption, followed by randomization to 12-day experimental period during which liquid formulas were consumed (35% of energy as fat). One group received 85% medium-chain triglycerides, and the control group received 100% long-chain triglycerides.

Statistical Analysis

Subjects' demographic and other baseline characteristics were compared using two-sample T-tests, Wilcoxon rank sum tests and Fisher's exact tests. Stool and urine assessments were compared between groups at the initial experimental period using two-sample T-tests. Changes from initial to final experimental periods were assessed by means of ANCOVA. Changes in pooled intake, body weight, and the number and consistency of bowel movements were also assessed using ANCOVA.

Data Collection Summary:

Timing of Measurements

Measurements included stool number, consistency, weight, and fat and nitrogen content; urine nitrogen and creatinine levels; and body weight. Laboratory analysis was completed during the workup period, days four to six and days 13 to 15. 72-hour stool collection, severity score. 24-hour urine collection and weights were completed daily.

Dependent Variables

  • Stool collections analyzed for weight, volume, water, nitrogen and fat content
  • Fat absorption calculated on basis of subtracting stool fat from fat intake
  • 24-hour urine collections analyzed for nitrogen content, creatinine levels and total volume
  • Weight.

Independent Variables

Randomization to 12-day experimental period in which liquid formulas were consumed (35% of energy as fat). One group received 85% medium-chain triglycerides and the control group received 100% long-chain triglycerides.

 

Description of Actual Data Sample:

Initial N: 31 enrolled in work-up period; six did not have fat malabsorption.

Attrition (final N):  24 subjects (23 men, 1 woman), 11 in MCT group, 13 in control group; 1 had a systemic infection

Age: Mean age, 37 years

Ethnicity: 21 subjects were white, 3 were black

Anthropometrics: There were no statistically significant differences between groups

Location: Alabama.

 

Summary of Results:

Other Findings

There were no differences between groups during the work-up period.

Within-group comparisons indicated that subjects fed the MCT formula showed significantly decreased stool fat and stool nitrogen content (P=0.01 and P=0.03, respectively) and increased fat absorption (P=0.03), whereas those fed the control formula did not.

Differences in stool fat between the groups were not statistically significant. However, the difference in fat absorption from the initial to final formula period was significant (P=0.04).

Subjects consuming the MCT formula also tended to have a decreased number of bowel movements and abdominal symptoms, whereas subjects fed the control formula showed no improvement.

All subjects maintained their body weights.  

Author Conclusion:

Our findings suggest that bowel rest from solid food, regardless of the type of dietary fat involved, results in similar gastrointestinal outcomes, except for fat absorption. In providing optimal nutrition care for patients with AIDS-associated malabsorption, dietitians may find it advantageous to recommend a defined liquid diet, particularly an MCT-based formula, to relieve symptoms of steatorrhea and concomitant weight loss. Our results may encourage other researchers to conduct studies of longer duration to determine whether MCT-enriched enteral formulas have a demonstrable effect on preserving or improving nutritional status in patients with AIDS and fat malabsorption. Such studies should address nutritional status, clinical outcome, cost-benefit and cost-effectiveness issues.

Funding Source:
Reviewer Comments:

Small number of subjects and subject number not equal between groups. Authors note short duration of experimental period (12 days).

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) Yes
  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) Yes
 
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? ???
  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? ???
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) ???
  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.) 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? Yes
  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? Yes
  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? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? Yes
  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? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.6. Were extra or unplanned treatments described? Yes
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  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)? 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? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? ???
  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