[Systematic review and meta-analysis of randomized controlled trials comparing Chinese patent medicines Compound Danshen Dripping Pills and Di'ao Xinxuekang in treating angina pectoris].

Background: Chinese patent medicines Compound Danshen Dripping Pills (DSP) and Di'ao Xinxuekang (DXK) capsules were both found effective in treating angina pectoris. However, there is no systematic review comparing their efficacy.
Objective: This systematic review aims to compare the efficacy of DSP and DXK in treating angina pectoris based on randomized controlled trials (RCTs) comparing their efficacy.
Search Strategy: RCT reports published between 1994 and 2011 were retrieved from databases including China Doctoral Dissertations Full-text Database, Chinese Journal Full-text Database, China Master's Theses Full-text Database, Wanfang Data, Cochrane Library, Excerpts Medica Database, ScienceDirect, MEDLINE (EBSCOhost) and PubMed. The last retrieval was performed on April 7, 2011.
Inclusion Criteria: RCT reports comparing the effects of DSP and DXK were included, regardless publishing language.
Data Extraction and Analysis: Included RCT reports were assessed for their study quality by using the Jadad scale and the Cochrane risk of bias tool. Data including overall effect and electrocardiography (ECG) improvements were extracted from the included RCTs for meta-analysis. The effect sizes based on overall and ECG diagnosis were measured by odds ratio (OR) and 95% confidence interval (CI). Subgroup analysis and sensitivity analysis were also performed.
Results: Nine RCT reports with 926 participants were included. Eight were scored 2 and the other one was scored 4 by using the Jadad scale. The OR between DSP and DXK based on overall diagnosis was 2.06 (95% CI: 1.03-4.12; P(overall)=0.04). Six out of the nine included RCTs reported ECG data. The OR between DSP and DXK based on the ECG diagnosis was 1.92 (95% CI: 1.23-3.00; P(ECG)=0.004). The OR results were stable under subgroup analysis and sensitivity analysis.
Conclusion: DSP was consistently more effective than DXK according to meta-analysis, which was verified by subgroup analysis and sensitivity analysis. However, more RCTs of higher quality are needed for further confirmation.