Potassium and its effect on natriuresis and cardiovascular outcomes in health and kidney disease

In this thesis, we explored the complex relationship between potassium intake, natriuresis, blood pressure (BP), and cardiovascular disease (CVD) outcomes in health and chronic kidney disease (CKD). In the first chapter, we studied dietary potassium intake in the general population and found that higher intake was associated with lower systolic BP and reduced CVD risk—particularly in women. Notably, in women, the association between potassium intake and systolic BP was modified by sodium intake. In the following chapters we examined the acute effects of a single oral potassium load on potassium and sodium balance. In healthy individuals, both changes in acid–base balance and aldosterone levels contributed to potassium uptake and excretion. Moreover, in healthy individuals, natriuresis increased in response to a single oral load of potassium, while in patients with CKD G3b–4 potassium-induced natriuresis was absent. Next, we evaluated the effects of 14-d supplementation of potassium chloride in patients with CKD G3b–4. We showed that potassium supplementation increased plasma potassium, but had no significant effect on BP or eGFR. Also, in proteinuric CKD patients, the proteinuria, but not BP-lowering response to losartan during a habitual high-sodium diet was hampered during high potassium intake. However, differences disappeared after sodium status change by low-sodium diet. Finally, we reviewed potassium management in haemodialysis patients, emphasizing the need for individualized strategies. Altogether, this thesis highlights that the beneficial effects of potassium may highly depend on patient characteristics including sex, sodium intake, kidney function and use of single renin-angiotensin-system (RAS) blockers.