Efficacy and safety of Songling Xuemaikang capsule for essential hypertension: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND: Hypertension is one of the most significant public health challenges worldwide. An increasing number of patients prefer to incorporate traditional Chinese medicine into their hypertensive care. The Songling Xuemaikang capsule (SXC), a Chinese herbal formula, is widely used in China for essential hypertension. PURPOSE: To assess the efficacy and safety of SXC for essential hypertension. STUDY DESIGN: Systematic review and meta-analysis of randomized controlled trials (RCTs). METHODS: We conducted a systematic literature search of seven databases to identify randomized controlled trials of SXC for hypertension. The outcome measures included blood pressure parameters and patient-reported outcomes. Potential heterogeneity between the studies was resolved by subgroup and sensitivity analyses. The quality of the results was evaluated using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach. RESULTS: A total of 34 trials with 4306 patients were included. The results showed that SXC plus antihypertensive drugs produced a greater effect on reducing systolic blood pressure (SBP) (MD: -7.54 mmHg; 95% CI: -8.92, -6.17; p < 0.00001), diastolic blood pressure (DBP) (MD: -6.42 mmHg; 95% CI: -7.54, -5.29; p < 0.00001), 24-hour SBP (MD: -6.88 mmHg; 95% CI: -8.36, -5.39; p < 0.00001), and 24-hour DBP (MD: -4.31 mmHg; 95% CI: -6.55, -2.07; p = 0.0002) and improving hypertensive symptoms (SMD: -1.09; 95% CI: -1.34, -0.84; p < 0.00001) than antihypertensive drugs alone. SXC monotherapy was less effective than antihypertensive drugs for 24-hour SBP reduction (MD: 2.07 mmHg; 95% CI: 0.19, 3.96; p = 0.03). No significant difference was observed in the incidence of adverse events between the SXC and control groups. CONCLUSION: SXC is beneficial for essential hypertension; it can lower BP, improve hypertensive symptoms and is well tolerated.