Effects of Combining Herbal Medicine with Western Medicine on Patients with Variant Angina Pectoris: Systemic Review and Meta-analysis (PRISMA Compliant)

Objective: The aim was to compare the effectiveness of traditional Korean herbal medicine versus conventional management in patients with variant angina.Methods: We searched several databases, including five international databases and five domestic electronic databases, for relevant studies. A search was conducted using keywords such as “Korean medicine”, “Chinese medicine”, and “variant angina pectoris” on February 28, 2024. Two review authors independently extracted the data. We assessed the risk of systemic errors by evaluating risk domains using the Cochrane risk of bias tool. When appropriate, meta-analyses were performed.Results: Twenty-nine trials were included in the review. For these reports, a meta-analysis was performed using RevMan 5.3. The meta-analysis showed that the treatment group (herbal medicine combined with Western medicine) had a significantly higher clinical effective rate and ECG effective rate than the control group (Western medicine only) (OR 4.56 95% CI 3.43 to 6.07, P<0.00001, I2=0%) (OR 3.20 95% CI 2.07 to 4.93, P<0.00001, I2=0%). The treatment group also showed a significantly reduced frequency and duration of angina (MD -1.77 95% CI -2.08 to -1.46, P=0.006, I2=50%) (MD -1.51 95% CI -2.24 to -0.78, P<0.00001, I2=0%).Conclusion: This systematic review and meta-analysis suggests that the combined treatment of herbal medicine and Western medicine can be effective in treating variant angina. However, the results might be somewhat biased because of the unknown or high risk of bias in the included trials and the insufficiency of subgroup studies. Therefore, further studies should consider a large number of high-quality clinical studies.