Banxia baizhu tianma decoction for essential hypertension: a systematic review of randomized controlled trials

Objectives. To assess the current clinical evidence of Banxia Baizhu Tianma Decoction (BBTD) for essential hypertension (EH). Search Strategy. Electronic databases were searched until July 2012. Inclusion Criteria. We included randomized clinical trials testing BBTD against placebo, antihypertensive drugs, or combined with antihypertensive drugs against antihypertensive drugs. Data Extraction and Analyses. Study selection, data extraction, quality assessment, and data analyses were conducted according to Cochrane standards. Results. 16 randomized trials were included. Methodological quality of the included trials was evaluated as generally low. 2 trials compared prescriptions based on BBTD using alone with antihypertensive drugs. Meta-analysis showed no significant effect of modified BBTD compared with captopril in systolic blood pressure (MD: -0.75 (-5.77, 4.27); P = 0.77) and diastolic blood pressure (MD: -0.75 (-2.89, 1.39); P = 0.49). 14 trials compared the combination of BBTD or modified BBTD plus antihypertensive drugs with antihypertensive drugs. Meta-analysis showed there are significant beneficial effect on systolic blood pressure in the combination group compare to the antihypertensive drugs (MD: -4.33 (-8.44, -0.22); P = 0.04). The safety of BBTD is uncertain. Conclusions. There is encouraging evidence of BBTD for lowering SBP, but evidence remains weak. Rigorously designed trials are warranted to confirm these results.