CI: Enteral Nutrition and Fiber (2011)


Hart GK, Dobb GJ. Effect of a fecal bulking agent on DIARRHEA during enteral feeding in the critically ill. J Parenter Enteral Nutr. 1988 Sep-Oct; 12 (5): 465-468. PMID: 3141642.

PubMed ID: 3141642
Study Design:
Randomized Controlled Trial
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

Determine whether addition of fiber to EN given to critically-ill patients would reduce incidence of diarrhea.

Inclusion Criteria:
  • All patients eligible if started on EN in Royal Perth Hospital ICUs
  • EN for three or more days.
Exclusion Criteria:
  • Known diarrheal illness (Crohn's disease, ulcerative colitis, ischemic colitis, melena)
  • GI surgery in 14 days before EN started
  • Patients with special dietary requirements
  • Patients fed EN for less than three days (excluded from data analysis).
Description of Study Protocol:
  • Recruitment: All eligible patients admitted to Royal Perth Hospital ICUs
  • Design: RCT
  • Blinding used: Double-blinded.


  • Treatment Group had 3.5g ispaghula husk dissolved in 75ml of water, given through feeding
  • Control Group received a placebo of Weetabix wheat-based breakfast cereal with identical coloring and flavor.

Statistical Analysis

Wicoxon Rank Sum test for non-parametric data for comparison of diarrhea score.

Data Collection Summary:
  • Timing of measurements: Values for all bowel movments in each 24-hour period (midnight to midnight) added to give daily diarrhea score
  • Dependent variables: Diarrhea (two or more liquid or semi-soft bowel movements a day), as measured by a semi-quantitative diarrhea score, based on volume and consistency of the stool
  • Independent variables: Placebo or fiber sachet dissolved in 75ml water and added to EN every 12 hours
  • Control variables: All patients received Osmolite by continuous gravity-fed infusion.
Description of Actual Data Sample:

Initial N

68 (43 males, 25 females).

Attrition (Final N)



  • Treatment Group: 47.1±20.8
  • Control Group: 48.5±18.6.


Not decribed.

Other Relevant Demographics

Not descrbed.


Not described.



Summary of Results:

Key Findings

NS difference in diarrhea scores between groups.


Treatment with Ispaghula Husk (Psyllium)

Control Group

Statistical Significance of Group Difference

Patients with Diarrhea on Any Day N ( %)

19 (54%)

19 (58%)


Total Feeding Days




Days with Diarrhea

 66 (23%)

 68 (23%)


Other Findings

  • Weak correlation between diarrhea and number of antibiotics each patient received (R=0.2, P<0.05)
  • Correlation of positive non-enteric bacterial cultures (R=0.2, P<0.05)
  • Patients with three or more positive non-enteric cultures significantly more likely to have diarrhea (P<0.002).
Author Conclusion:

Addition of ispaghula husk to EN did not result in difference in occurrence of diarrhea.

Funding Source:
Reckitt and Coleman, Australia supplied Fybogel and placebo
University/Hospital: Royal Perth Hospital, Western Australia
In-Kind support reported by Industry: Yes
Reviewer Comments:

Negative findings: Study likely underpowered.

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? 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? N/A
  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.) 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? No
  8.1. Were statistical analyses adequately described and the results reported appropriately? N/A
  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)? Yes
  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? No
  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? N/A
  9.2. Are biases and study limitations identified and discussed? N/A
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