Chuanxiong preparations for preventing stroke: Cochrane systematic review
Assessed as up to date: 2008/09/10
Stroke is a major healthcare problem and is one of the leading causes of death and serious long-term disability. Prevention of stroke is considered an important strategy. Chuanxiong is traditionally used in China in the treatment and prevention of stroke. In recent years, Chinese researchers have developed new patented Chuanxiong preparations.
To assess the effects and safety of Chuanxiong preparations in preventing stroke in high-risk adults.
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2008, Issue 1), MEDLINE (1950 to March 2008), EMBASE (1980 to March 2008), AMED (1985 to March 2008), Chinese Biomedical Database (CBM) (1975 to March 2008), China National Knowledge Infrastructure (CNKI) (1994 to March 2008), and the VIP Database (1989 to March 2008). Trials registers were searched for ongoing studies. No language restrictions were applied.
Randomised controlled trials (RCTs) studying the effects of Chuanxiong preparations in preventing stroke were included.
Data collection and analysis
Three reviewers independently selected studies for inclusion and two reviewers independently extracted data. Authors of identified RCTs were telephoned to confirm the randomisation procedure. Outcomes assessed included: stroke, composite cardiovascular outcomes, changes in cardiovascular and cerebrovascular haemodynamic indices and adverse events. Peto odds ratio (OR) with 95% confidence intervals (CI) were calculated for dichotomous variables and mean differences for continuous outcomes.
Three RCTs (5042 participants) were included. One higher quality study (4415 participants) compared Nao-an capsule with aspirin for primary prevention in high-risk stroke populations. Nao-an capsule appeared to reduce the incidence of stroke compared with aspirin (OR 0.56 95% CI 0.33 to 0.96). One study of low methodological quality indicated that a self-prepared Xifenwan tablet reduced the incidence of stroke in people with transient ischaemia attack (TIA) (OR 0.18, 95% CI 0.04 to 0.78). The remaining low quality study indicated that "apoplexy 2 preventing dry ointment powder" appeared to reduce both fatal stroke and incidence of stroke (OR 0.21, 95% CI 0.10 to 0.43, and OR 0.28, 95% CI 0.16 to 0.49, respectively).
Nao-an capsule may be a choice for the primary prevention of stroke. However, the design of the study providing this evidence means that there was potential for results to have been affected by bias from the way participants may have been selected, or from investigators' conflicts of interests. There was a lack of description of the methodology in the two other studies therefore evidence from these was considered too weak to draw any firm conclusions. Further high quality research is required.
Yang Xunzhe, Zeng Xiaoxi, Wu Taixiang
Chuanxiong preparations to prevent stroke in people at high risk of stroke
Stroke is a major healthcare problem. It is one of the leading causes of death and serious long-term disability. Prevention of stroke is considered to be an important strategy. Some Traditional Chinese Medicines are used to try and prevent stroke because evidence suggests that they can improve blood circulation, dilate blood vessels, lower blood pressure, inhibit thrombosis, regulate lipid metabolism and other functions. We looked for evidence on the effects of Chuanxiong, a treatment widely used in China to treat and prevent stroke.
We found three trials that tested treatments based on Chuanxiong. One trial compared Nao-an capsule with aspirin for the primary prevention of stroke in people at high risk. This trial found that Nao-an capsule reduced the incidence of stroke. It may, therefore, be a choice for the primary prevention of stroke. However the design of the trial means that the results may have been affected by the way people were selected to take part in the study, and by potential conflicts of interest of the researchers.Two further trials were identified but they were of low quality and their evidence was weak. Further good quality research is required.
Implications for practice
Nao-an capsule may be a choice for the primary prevention of stroke in people at high risk of stroke. We do not intend to recommend the other two formula, Xifengwan and apoplexy 2 preventing dry ointment powder, in the secondary prevention of stroke because of insufficient evidence.
Implications for research
Nao-an capsule should be re-tested by trials of better design. These trials should use smaller community units, or individual participants, as the unit of randomisation in order to avoid any selection bias; it is also recommended that a third-party group conduct future trials so as to avoid potential conflicts of interest; changes of risk factors should be tested; and cost-effect analysis data should be reported.