title: Chinese herbal medicine for the treatment of primary hypertension: a methodology overview of systematic reviews.
abstract: Chinese herbal medicine has been used to treat hypertension in China and East Asia since centuries. In this study, we conduct an overview of systematic reviews of Chinese herbal medicine in the treatment of primary hypertension to 1) summarize the conclusions of these reviews, 2) evaluate the methodological quality of these reviews, and 3) rate the confidence in the effect on each outcome.
  
  
  
  We comprehensively searched six databases to retrieve systematic reviews of Chinese herbal medicine for primary hypertension from inception to December 31, 2015. We used AMSTAR to evaluate the methodological quality of included reviews, and we classified the quality of evidence for each outcome in included reviews using the GRADE approach.
  
  
  
  A total of 12 systematic reviews with 31 outcomes were included, among which 11 systematic reviews focus on the therapeutic effect of Chinese herbal medicine combined with conventional medicine or simple Chinese herbal medicine versus simple conventional medicine. Among the 11 items of AMSTAR, the lowest quality was "providing a priori design" item, none review conformed to this item, the next was "stating the conflict of interest" item, only three reviews conformed to this item. Five reviews scored less than seven in AMSTAR, which means that the overall methodological quality was fairly poor. For GRADE, of the 31 outcomes, the quality of evidence was high in none (0 %), moderate in three (10 %), low in 19 (61 %), and very low in nine (29 %). Of the five downgrading factors, risk of bias (100 %) was the most common downgrading factor in the included reviews, followed by imprecision (42 %), inconsistency (39 %), publication bias (39 %), and indirectness (0 %).
  
  
  
  The methodological quality of systematic reviews about Chinese herbal medicine for primary hypertension is fairly poor, and the quality of evidence level is low. Physicians should be cautious when applying the interventions in these reviews for primary hypertension patients in clinical practice.
authors.affiliation: School of Basic Medical Sciences, Lanzhou University, Lanzhou, 730000, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Xinke
authors.affiliation: School of Basic Medical Sciences, Lanzhou University, Lanzhou, 730000, China. lydj412@163.com.|Key Lab of Prevention and Treatment for Chronic Disease by Traditional Chinese Medicine of Gansu Province, Lanzhou, 730000, China. lydj412@163.com.|The Hospital Affiliated to Gansu College of TCM, Lanzhou, 730020, China. lydj412@163.com.
authors.forename: Li
authors.initials: L
authors.lastname: Yingdong
authors.affiliation: The Hospital Affiliated to Gansu College of TCM, Lanzhou, 730020, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Mingxia
authors.affiliation: Key Lab of Prevention and Treatment for Chronic Disease by Traditional Chinese Medicine of Gansu Province, Lanzhou, 730000, China.
authors.forename: Liu
authors.initials: L
authors.lastname: Kai
authors.affiliation: The Hospital Affiliated to Gansu College of TCM, Lanzhou, 730020, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Kaibing
authors.affiliation: The Hospital Affiliated to Gansu College of TCM, Lanzhou, 730020, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Yuqing
authors.affiliation: Key Lab of Prevention and Treatment for Chronic Disease by Traditional Chinese Medicine of Gansu Province, Lanzhou, 730000, China.
authors.forename: Sun
authors.initials: S
authors.lastname: Shaobo
authors.affiliation: Key Lab of Prevention and Treatment for Chronic Disease by Traditional Chinese Medicine of Gansu Province, Lanzhou, 730000, China.
authors.forename: Song
authors.initials: S
authors.lastname: Peng
authors.affiliation: Key Lab of Prevention and Treatment for Chronic Disease by Traditional Chinese Medicine of Gansu Province, Lanzhou, 730000, China.
authors.forename: Liu
authors.initials: L
authors.lastname: Bin
mesh_terms: D004365:Drugs, Chinese Herbal / Q000627:therapeutic use*; D000075222:Essential Hypertension / Q000188:drug therapy*; D006801:Humans; D008516:Medicine, Chinese Traditional; D017594:Publication Bias; D012107:Research Design / Q000592:standards*; D012196:Review Literature as Topic
chemical_list: D004365:Drugs, Chinese Herbal
keywords: Chinese herbal medicine; GRADE; Methodological quality; Overview; Primary hypertension; Quality of evidence