Randomized Controlled Trials of Tianma Gouteng Decoction Combined with Nifedipine in the Treatment of Primary Hypertension: A Systematic Review and Meta-Analysis

Abstract

Background. Hypertension is a primary risk factor for cardiovascular disease (CVD). Tianma Gouteng decoction (TGD), originating from Zabingzhengzhixinyi, has been used for thousands of years in China to treat hypertension, giddiness, and migraine. This updated meta-analysis aimed at assessing the efficacy and safety of TGD combined with nifedipine in the treatment of primary hypertension. Methods. Related research published prior to September 1, 2019, was found in electronic databases without language limitations. Fourteen studies were selected and analyzed for specified criteria, including the quality of the studies. All outcomes were recorded exhaustive. Data management and analysis were performed using RevMan 5.3 software. Results. A total of 1,537 (769 cases in the experimental group and 768 cases in the control group) patients were enrolled. The total efficacy rate was improved significantly for the combination of nifedipine with TGD compared to nifedipine treatment alone (I2 = 22%, RR = 1.17, and 95% CI: 1.12 to 1.22). Traditional Chinese medicine (TCM) symptoms of patients were obviously improved in the experimental group than in the control group (I2 = 44%, RR = 1.26, and 95% CI: 1.17 to 1.36). TGD combined with nifedipine shows a better effect than nifedipine in decreasing diastolic blood pressure (I2 = 95%, MD = −5.32, and 95% CI: −8.19 to −2.45) and systolic blood pressure (I2 = 98%, MD = −9.35, and 95% CI: −15.03 to −3.67) of patients. A sensitivity analysis was conducted for SBP and DBP by removing 2 studies and recalculated the combined estimate on remaining studies. The results of SBP showed a small heterogeneity (I2 = 17%, MD = −13.95, 95% CI: −14.86 to −13.05, and P<0.00001) when two studies (shicaihong 2017 and xiaoyugao 2017) were removed. And the results of DBP showed no heterogeneity (I2 = 0, MD = −8.36, 95% CI: −8.91 to −7.81, and P<0.00001) when two studies (panzhixiong 2019 and shicaihong 2017) were removed. Conclusion. The combination of TGD and nifedipine has a better effect in the treatment of hypertension, including blood pressure lowering and patients’ TCMs improving. However, our findings must be handled with care because of the small sample size and low quality of clinic trials cited. Other rigorous and large-scale RCTs are in need to confirm these results.