THE EFFECT OF POTASSIUM SUPPLEMENTATION ON ALDOSTERONE AND BLOOD PRESSURE: A SYSTEMATIC REVIEW AND META-ANALYSIS

Objective: Increased potassium intake can reduce blood pressure (BP) particularly in subjects with hypertension by favouring sodium excretion and promoting vasorelaxation. However, potassium intake also stimulates the activity of the renin-angiotensin-aldosterone system (RAAS) which is one of the main homeostatic pathways for BP regulation. This interaction however has not been extensively investigated. Here we perform a systematic review and meta-analysis of clinical trials to assess the effect of subacute potassium supplementation on plasma aldosterone concentration (PAC) and BP in adult individuals. Design and method: This systematic review and meta-analysis was carried out in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Three databases were searched: MEDLINE, EMBASE and The Cochrane Central Register of Controlled Trials (CENTRAL). Medical subject headings (MeSH) and non-MeSH terms were used to search the databases for relevant publications. Titles were firstly screened by title and abstract for relevance before full-text articles were assessed for eligibility according to a pre-defined inclusion and exclusion criterion. The keywords used included “aldosterone”, “potassium” and “RAAS”. The review protocol was registered on the PROSPERO database. Results: A total of 6395 articles were retrieved (after removal of duplicates) and after title/abstract screening, 124 full-text articles were assessed for eligibility. 38 met the pre-specified inclusion/exclusion criteria of including potassium and PAC (of which 17/38 also reported systolic BP (SBP)). Potassium supplementation caused a significant decrease in SBP (mean difference [95% CI] -3.48mmHg [-4.8, -2.1], P < 0.001) and an increase in both urinary potassium excretion (75.5mEq/day [59.6, 65.5], P < 0.001) and serum potassium (+0.43 [0.22, 0.64] mmol/L, P < 0.001). There was also an increase in PAC (standardised 0.395 [0.271, 0.519], P < 0.001). Meta-regression showed a significant positive correlation between change in PAC and change in urinary potassium (P < 0.001) but not with SBP (P = 0.93). Conclusions: In adult individuals, potassium supplementation lead to decrease in BP and increase in serum/urinary potassium and PAC. There is no correlation between the BP-lowering effect and rise in aldosterone.