Eleven studies with 247,510 participants were included in the meta-analysis. Quality scores ranged from 14 to 18. The mean weighted follow-up was 12.2 years (range five to 19).
Stroke: In 11 studies, a higher potassium intake (average weighted difference 42.1mmol per day) was significantly associated with a lower risk of stroke (RR 0.79, 95% CI 0.68 to 0.90). There was heterogeneity between the studies (Ι²=55%), but no evidence of publication bias. No influential studies were found in the sensitivity analysis.
Coronary heart disease: In six studies, there was no evidence of a relationship between higher potassium intake and the risk of coronary heart disease. The studies showed some heterogeneity (Ι²=45%). There was no evidence of publication bias. Sensitivity analysis showed that the removal of one study resulted in a statistically significant reduction in risk with a high intake.
Cardiovascular disease: In four studies, there was no evidence of a relationship between higher potassium intake and the risk of cardiovascular disease. Heterogeneity was high (Ι²=71%). There was no evidence of publication bias. Sensitivity analysis showed that the removal of one study resulted in a statistically significant reduction in risk, with a high intake, and removed the heterogeneity.
Subgroup analyses: Analysis of the 10 studies reporting relative risks adjusted for baseline blood pressure or hypertension status confirmed the inverse relationship between potassium intake and stroke risk and similar results were seen in an analysis of the nine studies that adjusted for baseline body mass index or body weight.
Meta-regression: This analysis found that the length of follow-up and the quality score were significant sources of heterogeneity for cardiovascular disease and including them in the analysis reduced the estimated between-study variance.