Presentations

Abstract

Introduction: For decades the discussion of modifiable risk factors for hypertension has been dominated by sodium intake. In recent years, there has been a growing interest in the role of potassium in modifying blood pressure. While the normal range for serum potassium is often accepted to be 3.5-5.2mmol/L, there is limited consensus on the relationship between serum potassium levels and risk for hypertension or on the ideal range of potassium for hypertensive patients.

Main Body: Objective To identify the current scientific consensus on the relationship between serum potassium to the prevalence, severity, and mortality of hypertension. Data Sources and Study Selection Pubmed and Medline were searched from 1999 to 2024. Search terms included hypertension and serum potassium. Included articles were peer reviewed studies on human participants with full English texts available. Secondary analyses and studies with non-generalizable data were excluded. Data Extraction and Synthesis Two reviewers independently investigated design, participant demographics, quality, and findings of studies. Due to heterogeneity of study designs, narrative synthesis was used to evaluate papers, and the consensus method was employed to resolve disagreements concerning quality and conclusions of papers. Results 10 papers including retrospective (4), prospective (3), case-control (2), and cross-over clinical trial (1) studies met inclusion criteria and were assessed. Among them, the average MINORS score was 15.33±2.67, indicating they were of relatively high quality, while the single clinical trial showed evidence of high bias using the Cochrane RoB2 tool for cross-over studies. Four papers showed evidence that low to low-normal serum potassium was linked to higher prevalence of hypertension. Two papers suggested plasma concentration and intracellular potassium concentration in RBCs were significantly lower in patients with hypertension with one study suggesting a negative linear relationship between intracellular potassium and severity of hypertension. An experimental study showed that after a 10-day period of low potassium intake, average SBP increased by 5 mmHg. Two retrospective studies reported all-cause mortality in patients with hypertension was U-shaped when compared to serum potassium levels with the lowest mortality in the interval of 4.1-4.4mmol/L, and there was increased short-term mortality when serum potassium level was <3.7 or >4.6 in patients who were started on antihypertensive therapy. A single paper found that serum potassium above 4.8mmol/L increased risk of hypertension by 84%.

Conclusion: Serum potassium shows promise as a predictor of health in pre-hypertensive and hypertensive patients. This systematic review reveals that the normal range for serum potassium may include values correlated to higher rates of hypertension at the low-normal or high-normal ends, worse outcomes for hypertensive treatment at a high-normal concentration, and increased rates of mortality in hypertensive patients if outside of a narrow range. Few papers investigated intracellular potassium concentrations, which may be a valuable marker for evaluating hypertensive disease severity. The lack of low bias trials assessing serum potassium modification in treating hypertension leaves a major gap in the current scientific understanding of this topic. Further high quality research is needed to better explore the relationship between serum potassium levels and hypertension.