To provide the first systematic review and meta-analysis of observational studies on the association of abnormal serum potassium and cardiovascular outcomes.Medline and ISI Web of Knowledge were systematically searched from inception until November 24, 2017. Data synthesis of relevant studies was performed using random effects model meta-analyses.Meta-analyses included 310,825 participants from 24 studies. In the older general population, low serum potassium was associated with a 1.6-fold increased risk of supraventricular arrhythmias (risk ratio [95% confidence interval] 1.62 [1.02-2.55]). Contrarily, high serum potassium was associated with increased cardiovascular mortality (CVM) (1.38 [1.14-1.66]). In patients with acute myocardial infarction, the risk of ventricular arrhythmias was increased for high serum potassium (2.33 [1.60-3.38]). A U-shaped association was observed with a composite cardiovascular outcome in hypertensive patients (2.6-fold increased risk with hypokalemia and 1.7-fold increased risk with hyperkalemia), with CVM in dialysis patients (1.1-fold increased risk with hypokalemia and 1.4-fold increased risk with hyperkalemia) and with CVM in heart failure patients (albeit not statistically significant). Further, only hyperkalemia was associated with an increased risk of a composite cardiovascular outcome in both dialysis (1.12 [1.03-1.23]) and chronic kidney disease (1.34 [1.06-1.71]) patients.Controlled clinical trials are needed to determine which populations may profit from more frequent potassium-monitoring and subsequent interventions, e.g., change or withdrawal of potassium-influencing drugs, in order to restore normal values and prevent cardiovascular outcomes.Registration in PROSPERO (Centre for Reviews and Dissemination University of York, York, UK): CRD42016048897 ( https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=48897 ).     «

To provide the first systematic review and meta-analysis of observational studies on the association of abnormal serum potassium and cardiovascular outcomes.Medline and ISI Web of Knowledge were systematically searched from inception until November 24, 2017. Data synthesis of relevant studies was performed using random effects model meta-analyses.Meta-analyses included 310,825 participants from 24 studies. In the older general population, low serum potassium was associated with a 1.6-fold increa...     »