Abstract 060: Increased Urinary Potassium Excretion Does Not Associate With Reduced Systolic Blood Pressure in the Dietary Approaches to Stop Hypertension Sodium Trial

Abstract

Aim: The 2019 National Academy of Science, Engineering and Medicine Dietary Reference Intakes (DRI) for Sodium (Na) and Potassium (K) Report concluded there remains insufficient evidence to establish potassium DRIs. This study investigated the association between Na and K excretion and blood pressure in salt sensitive (SS) vs. salt resistant (SR) subjects in the Dietary Approaches to Stop Hypertension Sodium (DASH-Na) Trial. Methods: Via the NHLBI BioLINCC we accessed the DASH-Na dataset containing data on systolic blood pressure (SBP), 24-h urinary Na and K excretion at screening (regular diet [no dietary intervention]; 186 SS and 222 SR adults) and post 1-month DASH diet (increased K intake; 72 SS and 123 SR adults). The relationships between SBP, urinary Na and K excretion and Na:K ratio were assessed via linear regression with SS vs. SR as a categorical factor. Results: At screening, on a regular diet, urinary Na excretion (adjusted for gender) positively correlated with increased SBP in SS but not SR individuals (SS - 1g increase in Na excretion increases SBP 1.1±0.3mmHg - up to 5g Na excretion/day). In contrast, despite urinary K excretion of <1g/day correlating with increased SBP in both SS and SS subjects, increased urinary K excretion (range 1-4g/day) did not correlate with changes in SBP in either SS or SR individuals. The urinary Na to K ratio (Na:K) was not significantly associated with SBP in SS or SR subjects. At the urinary Na excretion range 3-5g/day, equivalent to US Na intake, increased urinary K excretion had no effect on SBP in either SS or SR individuals. On the DASH diet; SBP was reduced in SS (-4.5±1.3mmHg) and SR (-8.3±0.8mmHg, P<0.05) subjects. However, no correlation was observed between the reduction in SBP and urinary K excretion or urinary Na:K ratio in either in SS or SR individuals on the DASH diet. Conclusion: These data show in the DASH-Na trial population increased urinary K excretion does not correlate with reductions in SBP irrespective of the salt sensitivity of blood pressure. Our data support the recent DRI recommendation not to propose K intake guidelines and suggest that further evidence is required to support the establishment of a Na:K intake ratio to reduce SBP.