Effects of Traditional Chinese Patent Medicine on Essential Hypertension: A Systematic Review

Traditional Chinese patent medicine (TCPM) is widely used for essential hypertension (EH) in China. However, there is no critically appraised evidence, such as systematic reviews or meta-analyses, regarding the potential benefits and disadvantages of TCPM to justify their clinical use and recommendation. The aim of this review was to systematically evaluate and meta-analyze the effects of TCPM for EH. Seven databases, the Cochrane Library, PubMed, EMBASE, the China National Knowledge Infrastructure, the Chinese Scientific Journal Database, the Chinese Biomedical Literature Database, and the Wanfang Database, were searched from their inception to August 2014 for relevant studies that compared one TCPM plus antihypertensive drugs versus antihypertensive drugs alone. The methodological quality of the included trials was assessed using the Cochrane risk-of-bias tool. The primary outcome measures were mortality or progression to severe complications and adverse events. The secondary outcome measures were blood pressure (BP) and quality of life (QOL). Seventy-three trials, which included 8138 patients, on 17 TCPMs were included. In general, the methodological quality was low. Two trials evaluated the effects of TCPMs on mortality and the progression to severe complications after treatment, and no significant difference was identified compared with antihypertensive drugs alone. No severe adverse events were reported. Thirteen TCPMs used in complementary therapy significantly decreased systolic BP by 3.94 to 13.50 mmHg and diastolic BP by 2.28 to 11.25 mmHg. QOL was significantly improved by TCPM plus antihypertensive drugs compared with antihypertensive drugs alone. This systematic review provided the first classification of clinical evidence for the effectiveness of TCPM for EH. The usage of TCPMs for EH was supported by evidence of class level III. As a result of the methodological drawbacks of the included studies, more rigorously designed randomized controlled trials that focus on mortality and cardiovascular events during long-term follow-up are warranted before TCPM can be recommended for hypertensive patients. Two TCPMs, Song ling xue mai kang capsules and Yang xue qing nao granules, should be prioritized for further research.