BACKGROUND:

Previous metaanalyses of potassium supplementation in patients with hypertension observed little or no benefit, but failed to account the amount of salt intake.

OBJECTIVE:

To assess the effect on blood pressure of potassium treatment in patients with high salt intake.

METHODS:

We meta-analyzed studies of patient populations with both high salt and potassium intake. We searched Medline, Google, major journals, Pubmed. Publication bias, lack of heterogeneity, and lack of robustness were assessed using standard procedures for such purposes.

RESULTS:

After the exclusion of 32 studies 10 studies were left in the meta-analysis. A pooled reduction of systolic blood pressure of -9.5 mmHg (95% confidence interval -10.8 to -8.1) and of diastolic blood pressure -6.4 mmHg (-7.3 to -5.6) was observed. These results were very heterogeneous (I2-values of 94 and 95%). After exclusion of single authored studies the results fell but remained statistically significant, -7.1 mmHg (-8.5 to -5.7), and -4.9 mmHg (-5.8 to -4.0). Heterogeneity of systolic blood pressure was no longer observed (I2-value 24.3%). Some publication bias was observed.

CONCLUSIONS:

1. Potassium treatment reduces the blood pressure substantially in hypertensive patients with salt-rich diets. 2. The difference in magnitude of blood pressure reduction between different studies is probably related to the amount of salt intake. 3. Patients with reduced salt intake benefit little from potassium treatment. 4. Major meta-analyses published to date have severely underestimated the potential benefit of potassium treatment in patients with hypertension.