Chinese herbal medicine for the treatment of prehypertension.

Objectives. To assess the current clinical evidence of Chinese herbal medicine (CHM) for prehypertension. Search Strategy. Electronic databases were searched until May, 2013. Inclusion Criteria. We included randomized clinical trials testing CHM against life style intervention and no treatment, or combined with life style intervention against life style intervention. Data Extraction and Analyses. Study selection, data extraction, quality assessment, and data analyses were conducted according to Cochrane standards. Results. Five trials were included. Methodological quality of the trials was evaluated as generally low. Only 1 trial reported allocation sequence. No trial reported the allocation concealment, double blinding, placebo control, presample size estimation, intention to treat analysis, and drop-out. All the included trials were not multicenter and large scale. Although meta-analysis showed that CHM is superior to either life style intervention group or no treatment group in decreasing blood pressure, we are unable to draw a definite conclusion on the effect of CHM due to the poor research methods used in the reviewed trials. The safety of CHM is still uncertain. Conclusions. There is no evidence to show that CHM is effective and safe for prehypertension due to serious methodological flaw of the reviewed trials. Rigorously designed trials are warranted to confirm these results.