NEWSLETTER ::: NO. 21 ::: DEC 2020 NCCR-SPONSORED IPAHK+ TRIAL GETS "POSH" The IPAHK+ (“Incidence of Primary Aldosteronism in Patients with Hypokalemia”) study was launched by the Endocrinology Clinic at the Zurich University Hospital's in October 2019, with the goal of investigating the incidence of primary hyperaldosteronism in a hypokalemic population. Since then, a hypokalemia registry specially set up for this purpose, which records all outpatients at the University Hospital Zurich with hypokalemia ≤ 3.0 mmol/l, has been growing continuously. The evaluation of the first 100 reported patients is currently underway and a corresponding publication is expected in spring 2021. In parallel, an exciting new sub-study has been developed called POSH: effects of Potassium Supplementation on blood pressure in patients with Hypokalemia. More than just an acronym, the name POSH is apt because the study is charmingly elegant in its design, procedures and scientific question. The “POSH” study is a prospective interventional trial examining the short-term effects of a one-week oral potassium substitution in hypertensive patients with severe hypokalemia (≤ 2.6 mmol/l). The main focus of the study is on the intra- and inter-individual effects of potassium supplementation on blood pressure and the regulation of the renin-angiotensin-aldosterone system. The study will further include a deep phenotyping approach by inclusion of plasma and urine steroid profiles and targeted plasma metabolomics and urinary exosomes. This sub-study is expected to uncover potential mechanisms involved in blood pressure pathophysiology and control. Furthermore, the multilayer omics-based characterization of “potassium-sensitive” and “potassium-resistant” individuals in terms of blood pressure reduction might help to distinguish between those subpopulations. The POSH trial thus represents a sophisticated approach towards personalized treatment of arterial hypertension based on individual potassium response.   NCCR Kidney.CH Institute of Anatomy University of Zurich Winterthurerstrasse 190 8057 Zurich | Switzerland www.nccr-kidney.ch katharina.thomas@uzh.ch Kidney - Control of Homeostasis is a Swiss research initiative, headquartered at University of Zurich, which brings together leading specialists in experimental and clinical nephrology and physiology from the universities of Bern, Fribourg, Geneva, Lausanne, and Zurich, and corresponding university hospitals.