title: Potassium supplementation for the management of primary hypertension in adults.
abstract: BACKGROUND
  Epidemiological evidence on the effects of potassium on blood pressure is inconsistent.
  
  
  OBJECTIVE
  To evaluate the effects of potassium supplementation on health outcomes and blood pressure in people with elevated blood pressure.
  
  
  METHODS
  We searched the Cochrane Library, MEDLINE, EMBASE, Science Citation Index, ISI Proceedings, ClinicalTrials.gov, Current Controlled Trials, CAB abstracts, and reference lists of systematic reviews, meta-analyses and randomised controlled trials (RCTs) included in the review.
  
  
  METHODS
  Inclusion criteria were: 1) RCTs of a parallel or crossover design comparing oral potassium supplements with placebo, no treatment, or usual care; 2) treatment and follow-up >=8 weeks; 3) participants over 18 years, with raised systolic blood pressure (SBP) >=140 mmHg or diastolic blood pressure (DBP) >=85 mmHg); 4) SBP and DBP reported at end of follow-up. We excluded trials where: participants were pregnant; received antihypertensive medication which changed during the study; or potassium supplementation was combined with other interventions.
  
  
  METHODS
  Two reviewers independently extracted data and assessed trial quality. Disagreements were resolved by discussion or a third reviewer. Random effects meta-analyses and sensitivity analyses were conducted.
  
  
  RESULTS
  Six RCT's (n=483), with eight to 16 weeks follow-up, met our inclusion criteria. Meta-analysis of five trials (n=425) with adequate data indicated that potassium supplementation compared to control resulted in a large but statistically non-significant reductions in SBP (mean difference: -11.2, 95% CI: -25.2 to 2.7) and DBP (mean difference: -5.0, 95% CI: -12.5 to 2.4). The substantial heterogeneity between trials was not explained by potassium dose, quality of trials or baseline blood pressure. Excluding one trial in an African population with very high baseline blood pressure resulted in smaller overall reductions in blood pressure (SBP mean difference: -3.9, 95% CI: -8.6 to 0.8; DBP mean difference: -1.5, 95% CI: -6.2 to 3.1). Further sensitivity analysis restricted to two high quality trials (n=138) also found non-significant reductions in blood pressure (SBP mean difference: -7.1, 95% CI: -19.9 to 5.7; DBP mean difference: -5.5, 95% CI: -14.5 to 3.5).
  
  
  CONCLUSIONS
  This systematic review found no statistically significant effect of potassium supplementation on blood pressure. Because of the small number of participants in the two high quality trials, the short duration of follow-up, and the unexplained heterogeneity between trials, the evidence about the effect of potassium supplementation on blood pressure is not conclusive. Further high quality RCTs of longer duration are required to clarify whether potassium supplementation can reduce blood pressure and improve health outcomes.
authors.forename: H O
authors.initials: HO
authors.lastname: Dickinson
authors.forename: D J
authors.initials: DJ
authors.lastname: Nicolson
authors.forename: F
authors.initials: F
authors.lastname: Campbell
authors.forename: F R
authors.initials: FR
authors.lastname: Beyer
authors.forename: J
authors.initials: J
authors.lastname: Mason
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000187:drug effects*; D019587:Dietary Supplements / Q000009:adverse effects; D006801:Humans; D006973:Hypertension / Q000628:therapy*; D017419:Potassium, Dietary / Q000008:administration & dosage* / Q000009:adverse effects; D016032:Randomized Controlled Trials as Topic
chemical_list: D017419:Potassium, Dietary