Clinical practice guidelines for hemodialysis patients call for restriction of dietary potassium intake due it concerns regarding potential hyperkalemia that could lead to malignant arrhythmias and mortality. However, according to Yoko Narasaki, MD, PhD, and colleagues, there are few data available informing recommendations for dietary potassium intake in patients on hemodialysis.
The researchers conducted a study to examine the relationship between dietary potassium intake and risk of mortality in a prospective cohort of hemodialysis patients. Results of the study were reported in the Journal of Renal Nutrition [2021;31(4):411-420].
The prospective Malnutrition, Diet, and Racial Disparities in Chronic Kidney Disease study included 415 hemodialysis patients from 16 outpatient dialysis clinics. Food Frequency Questionnaires administered from October 2011 to March 2015 were used to obtain data on dietary potassium intake. Cox regression models were used to assess associations between baseline dietary potassium intake stratified into tertiles and risk of mortality. Logistic regression was used to identify clinical characteristics associated with low dietary potassium intake (i.e., the lowest tertile).
In expanded case-mix Cox analyses, patients in the lowest tertile of dietary potassium intake had higher mortality (ref: highest tertile) (adjusted hazard ratio [aHR], 1.74; 95% confidence interval [CI], 1.14-2.66). Following adjustment for laboratory and nutritional covariates, the associations had greater magnitude of risk (aHR, 2.65; 95% CI, 1.40-5.04).
In expanded case-mix restricted cubic spline analyses, the was a monotonic increase in risk of death with incrementally lower intake of dietary potassium. In expanded case-mix logistic regression models, low dietary potassium intake was associated with female sex, higher serum bicarbonate, and lower dietary energy, protein, and fiber intake.
In conclusion, the researchers said, “In a prospective cohort of hemodialysis patients, lower potassium intake was associated with higher mortality risk. These findings suggest that excessive dietary potassium restriction may be deleterious in hemodialysis patients, and further studies are needed to determine the optimal dietary potassium intake in this population.”