Hawthorn extract for treating chronic heart failure: meta-analysis of randomized trials.

The aim of this meta-analysis was to assess the evidence from rigorous clinical trials of the use of hawthorn extract to treat patients with chronic heart failure. We searched the literature using MEDLINE, EMBASE, the Cochrane Library, CINAHL, CISCOM, and AMED. Experts on and manufacturers of commercial preparations containing hawthorn extract were asked to contribute published and unpublished studies. There were no restrictions about the language of publication. Two reviewers independently performed the screening of studies, selection, validation, data extraction, and the assessment of methodological quality. To be included, studies were required to state that they were randomized, double-blind, and placebo controlled, and used hawthorn extract monopreparations. Thirteen trials met all inclusion criteria. In most of the studies, hawthorn was used as an adjunct to conventional treatment. Eight trials including 632 patients with chronic heart failure (New York Heart Association classes I to III) provided data that were suitable for meta-analysis. For the physiologic outcome of maximal workload, treatment with hawthorn extract was more beneficial than placebo (weighted mean difference, 7 Watt; 95% confidence interval [CI]: 3 to 11 Watt; P < 0.01; n = 310 patients). The pressure-heart rate product also showed a beneficial decrease (weighted mean difference, -20; 95% CI: -32 to -8; n = 264 patients) with hawthorn treatment. Symptoms such as dyspnea and fatigue improved significantly with hawthorn treatment as compared with placebo. Reported adverse events were infrequent, mild, and transient; they included nausea, dizziness, and cardiac and gastrointestinal complaints. In conclusion, these results suggest that there is a significant benefit from hawthorn extract as an adjunctive treatment for chronic heart failure.