Traditional Chinese Medicine for Essential Hypertension:An Overview of Systematic Reviews

OBJECTIVE: To evaluate the methodological bias and the reliability of the conclusions of systematic reviews (SRs) about traditional Chinese medicine for essential hypertension. METHODS: We comprehensively searched PubMed, EMbase, The Cochrane library (Issue 4, 2014), CBM, CNKI and WanFang Data to collect SRs of traditional Chinese medicine for essential hypertension from the establishment time of databases to April 30th, 2014. The AMSTAR tool was applied for methodological quality assessment of included studies, and the GRADE system was applied for evidence quality assessment of included outcomes of SRs. RESULTS: A total of 12 SRs involving 31 outcomes were included, of which 11 SRs focused on the comparison of therapeutic effects between traditional Chinese medicine combined with western medicine and western medicine alone. Nine SRs adopted Jadad tool to assess methodological quality of included original studies. The results of assessment using AMSTAR showed that, among 11 items, there were the most problems concerning Item 1 “Was an ‘a prior’ design provided?” (none of the 12 SRs provided it); followed by Item 11 “Were potential conflict of interest included?” (nine SRs didn’t described it), and Item 6 “Were the characteristics of included studies provided” (six SRs didn’t provided it). The results of grading showed that, 29 outcomes were graded as “low” or “very low” quality. The main factors contributed to downgrading evidence quality were limitations (31 outcomes), followed by imprecision (12 outcomes), and inconsistency (13 outcomes). CONCLUSION: Currently, the methodological quality of SRs about traditional Chinese medicine for essential hypertension was poor on the whole, with low quality of evidence as well as lack of enough attention to the end outcomes of patients with essential hypertension. Thus, physicians should apply the evidence to make decision about traditional Chinese medicine for essential hypertension with caution in clinical practice.