Rising Trend of Hypokalemia Prevalence in the US Population and Possible Food Causes

Renal Hypokalemia: An Endocrine Perspective

The majority of disorders that cause renal potassium wasting present with abnormalities in adrenal hormone secretion. While these findings frequently lead patients to seek endocrine evaluation, clinicians often struggle to accurately diagnose these conditions, delaying treatment and adversely impacting patient care. At the same time, growing insight into the genetic and molecular basis of these disorders continues to improve their diagnosis and management. In this review, we outline a practical integrated approach to the evaluation of renal hypokalemia syndromes that are seen in endocrine practice while highlighting recent advances in understanding of the genetics and pathophysiology behind them.

Potassium intake: the Cinderella electrolyte

Dietary guidelines recommend intake targets for some essential minerals, based on observational and experimental evidence relating mineral intake levels to health outcomes. For prevention of cardiovascular disease, reducing sodium intake and increasing potassium intake are the principal tools. While reducing sodium intake has received greatest public health priority, emerging evidence suggests that increasing potassium intake may be a more important target for cardiovascular prevention. Increased potassium intake reduces blood pressure and mitigates the hypertensive effects of excess sodium intake, and the recent large Phase III SSaSS trial reported that increasing potassium intake (and reducing sodium intake) in populations with low potassium intake and high sodium intake, through salt substitution (25% KCl, 75%NaCl), reduces the risk of stroke in patients at increased cardiovascular risk. As key sources of potassium intake include fruit, vegetables, nuts, and legumes, higher potassium intake may be associated with healthy dietary patterns. The current review makes the case that increasing potassium intake might represent a more advantageous dietary strategy for prevention of cardiovascular disease. Future research should focus on addressing the independent effect of potassium supplementation in populations with low or moderate potassium intake, and determine effective strategies to increase potassium intake from diet.

Effect of Potassium Supplementation on Endothelial Function: A Systematic Review and Meta-Analysis of Intervention Studies

(1) Background: Endothelial dysfunction is an early predictor of cardiovascular diseases. Although a large body of evidence shows an inverse association between potassium intake and cardiovascular risk, the studies on endothelial function provided contrasting results. Thus, we carried out a systematic review and a meta-analysis of the available intervention studies of the potassium supplementation on endothelial function. (2) Methods: A systematic search of the online databases available (up to December 2022) was conducted including the intervention trials that reported flow-mediated dilation (FMD) changes-a non-invasive method of assessing endothelial function-after two different potassium intake regimens. For each study, the mean difference (MD) and 95% confidence intervals were pooled using a random effect model. (3) Results: Five studies met the pre-defined inclusion criteria and provided eight cohorts with 332 participants. In the pooled analysis, potassium supplementation was associated with a significant increase in FMD (MD: 0.74%), with a higher effect for a urinary potassium excretion higher than 90 mmol/day. There was a moderate heterogeneity among studies (I² = 59%), explained by the different amount of potassium supplementation. (4) Conclusions: The results of our meta-analysis indicate that dietary potassium supplement improves endothelial function. This effect is directly associated with the amount of potassium supplement. The findings support the campaigns in favour of an increase in dietary potassium intake to reduce cardiovascular risk.

Hypokalaemia associated with hydrochlorothiazide used in the treatment of hypertension in NHANES 1999-2018

Hydrochlorothiazide is the most common thiazide diuretic used for hypertension in the US. Yet, hypokalaemia is a well-recognised adverse effect. To evaluate the prevalence and factors associated with hypokalaemia (serum potassium < 3.5 mmol/L) among hydrochlorothiazide users, we included US adults aged ≥20 years in the 1999-2018 National Health and Nutrition Examination Survey. Participants were categorised according to the use of hydrochlorothiazide and other antihypertensive agents. Factors associated with hypokalaemia, including demographics and prescription patterns (monotherapy vs single-pill fixed-dose combination vs polytherapy) were studied using multivariable logistic regression. Hypokalaemia was present in 12.6% of the hydrochlorothiazide users, equivalent to ~2.0 million US adults. Women (adjusted OR, 2.22; 95% CI, 1.74-2.83), non-Hispanic blacks (adjusted OR, 1.65; 95% CI, 1.31-2.08), underweight (adjusted OR, 4.33; 95% CI, 1.34-13.95), and participants taking hydrochlorothiazide for five years or more (adjusted OR, 1.47; 95% CI, 1.06-2.04) had a higher risk of hypokalaemia. Compared to monotherapy, fixed-dose combination therapy (adjusted OR, 0.32; 95% CI, 0.21-0.48) was associated with the lowest risk. Among those taking potassium supplements, hypokalaemia was found in 27.2% of participants on monotherapy and 17.9% on polytherapy. The prevalence of hypokalaemia among hydrochlorothiazide users was considerable, even among participants who also took potassium supplements. Women, ethnic minorities, underweight, monotherapy, and participants with long-term therapy are more likely to have hypokalaemia. Regular monitoring of potassium and combination with potassium-sparing drugs are needed.

Rise in Potassium Deficiency in the US Population Linked to Agriculture Practices and Dietary Potassium Deficits

This paper, for the first time, provides evidence that current practices that lead to agricultural crop removal of potassium are unsustainable and likely contributed to the decline in dietary potassium intake and rise in hypokalemia prevalence in the US population. Potassium concentrations in beef, pork, turkey, fruit, vegetables, cereal crops, and so forth decreased between 1999 and 2015 based on the examination of potassium values of food items of USDA standard reference. Ratios of potassium input to removal by crops between 1987 and 2014, potassium in topsoil, and crop-available soil potassium in US farms all declined in recent years. Reported reductions in dietary potassium intake correspond to these decreases in the food supply and to increases in hypokalemia prevalence in the US population. Results of this paper provide new understanding on links between potassium management in agricultural practices and potassium intake deficits, which is needed for combating increasing hypokalemia prevalence in the US population.