Continuing Sodium Zirconium Cyclosilicate (SZC) After Discharge Study

This is a Phase 4, randomised, controlled, open-label, parallel-group, multicentre study in participants with CKD treated for HK whilst in hospital.

* Participants from 30 to 50 sites in 4 to 7 countries will be screened for enrolment. In total, up to a maximum of 163 participants will be enrolled, resulting in approximately 130 participants discharged and randomised and 104 evaluable participants (52 per arm). * The study plans to enrol approximately equal numbers of participants with mild HK (K+ between \> 5.0 and ≤ 5.5 mmol/L) and with moderate/severe HK (K+ between \> 5.5 and ≤ 6.5 mmol/L), with a minimum of 30% of the enrolled participants in either group. * During the in-hospital phase, participants will be treated with SZC as per local label, starting at baseline and based on local K+ measurement obtained within 24 hours of treatment initiation:).

* Participants with HK (K+ between \> 5.0 and ≤ 6.5 mmol/L):

1. stop current K-binder if any 2. start SZC correction dose (note: participants currently on SZC should continue SZC correction dose, up to 72 hours). * Participants currently receiving any treatment for the current episode of HK and are already NK at baseline (K+ ≤ 5.0 mmol/L): 1) stop any current K-binder, 2) start SZC maintenance dose (note: participants currently on SZC maintenance dose should continue SZC maintenance dose). * All treatment decisions, including modification of the ongoing therapy for HK must be based on the investigator's medical judgement of the participant's best interest. * At discharge, NK participants who have been treated with SZC for between 1 and 21 days whilst in hospital and are started on SZC maintenance dose will be randomised in a 1:1 ratio to one of the following arms:

* Arm A: Participants discharged with SZC, as per local label, to manage HK until the end of the outpatient phase * Arm B: Participants discharged with SoC, as per local practice, to manage HK until the end of study. Note: Participants intended to be discharged with a K+ binder (as per the site routine medical practice) will not be randomised and will be discontinued from the study. Still, participants randomised into Arm B may have a K-binder prescribed at Day 7 post-discharge, (or after Day 7 post-discharge), to treat confirmed HK or in case there is an increase in K+ level since discharge that, in the investigator's opinion, requires therapy. * The total duration of the study for each participant will be up to approximately 6 months. * Study visit schedule is as follows:

In-hospital phase: - The screening visit will occur while the participant is at the hospital (up to 21 days before discharge; medical monitor's approval may be sought for allowing longer duration hospital stays for specific participants) in order to check eligibility criteria