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HF: Hawthorn Berry (2007)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To assess the evidence from randomized controlled trials on the efficacy of hawthorn extract as an adjunct treatment for chronic heart failure.
Inclusion Criteria:
  • Randomized, double-blind and placebo-controlled
  • Used monopreparations of extracts of hawthorn leaf with flower
  • Chronic heart failure patients.
Exclusion Criteria:
  • Trials that were not randomized, placebo-controlled and double-blind
  • Studies not using monopreparations of hawthorn leaf with flower extract
  • Non-chronic heart failure patients.
Description of Study Protocol:
  • Systematic literature searches were conducted using the data sources MEDLINE, EMBASE, the Cochrane Library, CINAHL, CISCOM and AMED
    • Each database was searched from its inception until June 2002
    • Experts and manufacturers were asked to provide published or unpublished trials
    • Hand searches of medical journals and conference proceedings were also performed
    • The bibliographies of all located papers was searched.
  • There was no language restriction.
  • Search terms: Hawthorn, whitethorn, crataegus and weissdorn (common name for "hawthorn" in German)
  • The mean change in maximal workload, compared to baseline was defined as the primary endpoint.
Data Collection Summary:
  • Data was extracted systematically for patient characteristics, interventions and results. If information was insufficient, authors and the manufacturer of the preparation were contacted.
  • Methodological quality was assessed using a system developed by Jadad, which quantifies the likelihood of bias inherent in the trials, based on the description on randomization, blinding and withdrawals
  • The study selection, data extraction, validation and assessment were independently done by two reviewers. Disagreements in individual trials were largely due to errors in reading and were resolved via discussion.
  • The mean change in maximal workload, compared to baseline was defined as the primary endpoint
    • Weighted means and 95% CI were calculated using standard meta-analysis software
    • Summary estimates of the treatment effect were calculated using a random-effects model
    • The chi-square test for heterogeneity was performed to test whether the distribution of the results was compatible with the assumption that intertrial differences were attributable to chance alone
    • Publication bias was assessed using a funnel plot.
Description of Actual Data Sample:
  • 26 potentially relevant trials
  • 13 were excluded
    • Six were not randomized and placebo controlled
    • Four did not use monopreparations of extracts of hawthorn leaf with flower
    • One assessed healthy volunteers
    • One was published in duplicate
    • One did not include results.
  • Eight met inclusion criteria and provided data for the meta-analysis
  • Five others were included, but provided data not suitable for statistical pooling.
Summary of Results:
  • Dose: Daily dose of hawthorn extract was between 160mg and 1,800mg per day. All trials administered standardized hawthorn extracts. Seven of eight trials used hawthorn extract WS 1442, which is standardized to 18.8% oligomeric procyanidins.
  • Study length: Three to 16 weeks
  • Subjects: NYHA class I, II and III.

Maximal Workload (Bicycle Ergometry)

  • Four studies (N=310) measured changes in maximal workload
  • Significant increase in maximal workload with hawthorn extract vs. placebo (weight mean difference, seven watts; 95% CI, three to 11; P<0.01)
  • All used bicycle ergometry with an increase of 25 watts every two minutes, until the patients had to stop
  • This was not altered when one study was removed that gave a low vs. high dose regimen
  • No evidence of heterogeneity, P=0.5.

Pressure Heart Rate Product (Systolic BP in mmHg x Heart Rate per Minute/100)

  • Five studies measured BPH
  • Significant beneficial effect of hawthorn (weight mean difference, -20; 95% CI, -32 to -8; N=264).

Exercise Tolerance

  • Two studies measured exercise tolerance
  • Marginally non-significant effect (weight mean difference, 117 watt min; 95% CI, -1 to 235 watt min; N=98).

Dyspnea and Fatigue

  • Symptom score developed by von Zerssen and used in two trials
  • Differential effect in favor of hawthorn subjects (weight mean average, -6; 95% CI -9 to -2; N=169).

Side Effects

  • Most common adverse event was dizziness or vertigo (N=8)
  • Five trials reported no adverse events in patients receiving hawthorn.
Author Conclusion:

Results suggest that, compared to placebo, hawthorn extract increases the maximal workload in patients with chronic heart failure. This conclusion however, is based on a small number of studies and patients.

Funding Source:
University/Hospital: Unveristy of Exeter and Plymoth
Reviewer Comments:
  • Authors were very clear that this is only of studies that used monopreparations of extracts of hawthorn leaf with flower
  • Subjects in eight of the 13 trials were also treated with conventional medications, including ACE inhibitors and  calcium antagonists. As the authors point out, this leaves some uncertainty as to whether the benefit in this trial is completely due to hawthorn extract.
  • Funding bias does not seem likely.
Quality Criteria Checklist: Review Articles
Relevance Questions
  1. Will the answer if true, have a direct bearing on the health of patients? Yes
  2. Is the outcome or topic something that patients/clients/population groups would care about? Yes
  3. Is the problem addressed in the review one that is relevant to dietetics practice? Yes
  4. Will the information, if true, require a change in practice? Yes
 
Validity Questions
  1. Was the question for the review clearly focused and appropriate? Yes
  2. Was the search strategy used to locate relevant studies comprehensive? Were the databases searched and the search termsused described? Yes
  3. Were explicit methods used to select studies to include in the review? Were inclusion/exclusion criteria specified andappropriate? Wereselectionmethods unbiased? Yes
  4. Was there an appraisal of the quality and validity of studies included in the review? Were appraisal methodsspecified,appropriate, andreproducible? Yes
  5. Were specific treatments/interventions/exposures described? Were treatments similar enough to be combined? Yes
  6. Was the outcome of interest clearly indicated? Were other potential harms and benefits considered? Yes
  7. Were processes for data abstraction, synthesis, and analysis described? Were they applied consistently acrossstudies and groups? Was thereappropriate use of qualitative and/or quantitative synthesis? Was variation in findings among studies analyzed? Were heterogeneity issued considered? If data from studies were aggregated for meta-analysis, was the procedure described? Yes
  8. Are the results clearly presented in narrative and/or quantitative terms? If summary statistics are used, are levels ofsignificance and/or confidence intervals included? Yes
  9. Are conclusions supported by results with biases and limitations taken into consideration? Are limitations ofthe review identified anddiscussed? Yes
  10. Was bias due to the review's funding or sponsorship unlikely? Yes