Is additional hawthorn extract on top of conventional treatment more effective in treating patients with chronic heart failure, as compared to conventional treatment alone?
Date of publication of systematic review: January 2008
Design
Systematic review of 9 randomized controlled trials (RCTs).
Participants
669 adult patients diagnosed with chronic heart failure, categorized according to the NYHA classification (mean age range: 55 to 84 years, male % range: 25% to 60%).
Intervention
Conventional treatment plus oral preparations containing standardized extract of hawthorn leaf and flower, with a daily dosage ranged between 160mg to 1800 mg. Duration of treatment range from 3 to 16 weeks.
Comparator
Comparison: Conventional treatment plus hawthorn extract versus conventional treatment plus placebo.
Major Outcomes
Outcome 1: Change in maximum work load (Watt) from baseline to end of treatment;
Outcome 2: Change in exercise tolerance (Watt min) from baseline to end of treatment;
Outcome 3: Change in pressure-heart rate product (mmHg/min) from baseline to end of treatment.
Settings
The trials were conducted in outpatient settings.
Comparison    Conventional treatment plus oral preparations containing extract of hawthorn versus conventional treatment plus placebo
Main Results
Compared to placebo, hawthorn extract showed significant increase in maximal workload (pooled weighted mean difference (pooled WMD): 5.35, 95% CI: 0.71 to 10.00) and exercise tolerance (pooled WMD: 122.76, 95% CI: 32.74 to 212.78), and a reduction in the pressure-heart rate product (pooled WMD: -19.22, 95% CI: -30.46 to -7.98), with conventional treatment applied in both groups.
Comparison: Conventional treatment plus hawthorn extract versus conventional treatment plus placebo amongst patients with chronic heart failure
Outcomes (units) No. of studies (Total number of participants) Mean / No. of participants Heterogeneity test (I2) Pooled WMD (95% CI) Overall quality of evidence*
Intervention Comparator
1 (Watt) 5(380) 8.19/224 2.84/156 23% 5.35 (0.71 to 10.00) High
2 (Watt min) 2(98) 88.30/49 -34.46/49 0% 122.76 (32.74 to 212.78) High
3 (mmHg/min) 5(329) -15.80/163 3.43/166 80% -19.22 (-30.46 to -7.98) Moderate
Keys: WMD = weighted mean difference; CI = confidence interval.
Comparison    Conventional treatment plus oral preparations containing extract of hawthorn versus conventional treatment plus placebo
Main Results
Compared to placebo, hawthorn extract showed significant increase in maximal workload (pooled weighted mean difference (pooled WMD): 5.35, 95% CI: 0.71 to 10.00) and exercise tolerance (pooled WMD: 122.76, 95% CI: 32.74 to 212.78), and a reduction in the pressure-heart rate product (pooled WMD: -19.22, 95% CI: -30.46 to -7.98), with conventional treatment applied in both groups.
Comparison: Conventional treatment plus hawthorn extract versus conventional treatment plus placebo amongst patients with chronic heart failure
Outcomes (units) 1 (Watt) 2 (Watt min) 3 (mmHg/min)
No. of studies (Total number of participants) 5(380) 2(98) 5(329)
Mean / No. of participants Intervention 8.19/224 88.30/49 -15.80/163
Comparator 2.84/156 -34.46/49 3.43/166
Pooled WMD (95% CI) 5.35 (0.71 to 10.00) 122.76 (32.74 to 212.78) -19.22 (-30.46 to -7.98)
Overall quality of evidence* High High Moderate
Keys: WMD = weighted mean difference; CI = confidence interval.
Conclusion
Benefits
Compared to conventional treatment plus placebo, conventional treatment plus hawthorn extract was effective in improving maximal and exercise tolerance, as well as in reducing the pressure-heart rate product amongst patients with chronic heart failure. For outcomes 1 and 2, the overall quality of evidence is high. Further research is unlikely to have an important impact on our confidence in this estimate of effect. For outcome 3, the overall quality of evidence is moderate. Further research is fairly likely to have an important impact on our confidence in this estimate of effect.
Harms
No data on cardiac related mortality and morbidity were reported in all but one trial. This trial reported deaths (three in treatment, one in control group) without providing further details on possible reasons. Other reported adverse events were infrequent, mild, and transient, which included nausea, dizziness, and gastrointestinal complaints.
Link to Original Article
http://www.ncbi.nlm.nih.gov/pubmed/18254076
The synopsis is based on the following article:
Pittler MH, Guo R, Ernst E. Hawthorn extract for treating chronic heart failure. Cochrane Database Syst Rev. 2008 Jan 23;(1):CD005312


* Interpretation of quality assessment results:
• Very low: Further research is most likely to have an important impact on our confidence in this estimate of effect.
• Low: Further research is likely to have an important impact on our confidence in this estimate of effect.
• Moderate: Further research is fairly likely to have an important impact on our confidence in this estimate of effect.
• High: Further research is unlikely to have an important impact on our confidence in this estimate of effect.
• Very high: Further research is most unlikely to have an important impact on our confidence in this estimate of effect.

Details of assessment method can be found at Chung VC, Wu XY, Ziea ET, Ng BF, Wong SY, Wu JC. Assessing internal validity of clinical evidence on effectiveness of CHinese and integrative medicine: Proposed framework for a CHinese and Integrative Medicine Evidence RAting System (CHIMERAS). European Journal of Integrative Medicine. 2015 Aug 31;7(4):332-41.