title: Hyperuricemia and risk of incident hypertension: a systematic review and meta-analysis of observational studies.
abstract: BACKGROUND
  Observational studies of the relationship between hyperuricemia and the incidence of hypertension are controversial. We conducted a systematic review and meta-analysis to assess the association and consistency between uric acid levels and the risk of hypertension development.
  
  
  METHODS
  We searched MEDLINE, EMBASE, CBM (Chinese Biomedicine Database) through September 2013 and reference lists of retrieved studies to identify cohort studies and nested case-control studies with uric acid levels as exposure and incident hypertension as outcome variables. Two reviewers independently extracted data and assessed study quality using Newcastle-Ottawa Scale. Extracted information included study design, population, definition of hyperuricemia and hypertension, number of incident hypertension, effect sizes, and adjusted confounders. Pooled relative risks (RRs) and corresponding 95% confidence intervals (CIs) for the association between hyperuricemia and risk of hypertension were calculated using a random-effects model.
  
  
  RESULTS
  We included 25 studies with 97,824 participants assessing the association between uric acid and incident hypertension in our meta-analysis. The quality of included studies is moderate to high. Random-effects meta-analysis showed that hyperuricemia was associated with a higher risk of incident hypertension, regardless of whether the effect size was adjusted or not, whether the data were categorical or continuous as 1 SD/1 mg/dl increase in uric acid level (unadjusted: RR = 1.73, 95% CI 1.46∼2.06 for categorical data, RR = 1.22, 95% CI 1.03∼1.45 for a 1 SD increase; adjusted: RR = 1.48, 95% CI 1.33∼1.65 for categorical data, RR = 1.15, 95% CI 1.06∼1.26 for a 1 mg/dl increase), and the risk is consistent in subgroup analyses and have a dose-response relationship.
  
  
  CONCLUSIONS
  Hyperuricemia may modestly increase the risk of hypertension incidence, consistent with a dose-response relationship.
authors.affiliation: Department of Evidence-Based Medicine and Clinical Epidemiology, West China Hospital, Sichuan University, Chengdu, China.
authors.forename: Ji
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Evidence-Based Medicine and Clinical Epidemiology, West China Hospital, Sichuan University, Chengdu, China.
authors.forename: Tianqiang
authors.initials: T
authors.lastname: Qin
authors.affiliation: Department of Evidence-Based Medicine and Clinical Epidemiology, West China Hospital, Sichuan University, Chengdu, China.
authors.forename: Jianrong
authors.initials: J
authors.lastname: Chen
authors.affiliation: Second Affiliated Hospital of Chengdu University of TCM, Chengdu University of TCM, Chengdu, China.
authors.forename: Yulin
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Cardiology, Mianyang People's Hospital, Mianyang City, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China.
authors.forename: He
authors.initials: H
authors.lastname: Huang
authors.affiliation: Department of Evidence-Based Medicine and Clinical Epidemiology, West China Hospital, Sichuan University, Chengdu, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
mesh_terms: D006801:Humans; D006973:Hypertension / Q000097:blood / Q000209:etiology*; D033461:Hyperuricemia / Q000097:blood / Q000150:complications*; D015994:Incidence; D012306:Risk; D014527:Uric Acid / Q000097:blood*
chemical_list: D014527:Uric Acid