Introduction: The impact of recurrent hyperkalemia (rHK) on the time to cardiovascular (CV) outcomes and mortality in patients with chronic kidney disease (CKD) has not been well studied. This real-world study described and compared rates of CV outcomes and all-cause mortality between patients with rHK and matched patients without HK (nonHK).Methods: Patients with rHK were matched 1:1 to nonHK controls via exact and propensity score matching with the date of rHK or nonHK as index. Patients were adults with stage 3 or 4 CKD identified from Optum’s de-identified Market Clarity Data spanning 1/2016 to 8/2022. For each outcome sample, the corresponding CV events in baseline were excluded. CV outcomes included major adverse cardiovascular events plus (MACE+; all-cause mortality or inpatient [IP] heart failure, myocardial infarction, or stroke) and IP cardiac arrhythmia. Rates of CV outcomes and mortality were compared between matched cohorts using cause-specific Cox proportional hazard models and reported as hazard ratios (HR) with 95% confidence intervals (CI). Subgroups analyses were conducted by renin-angiotensin-aldosterone system inhibitor (RAASi) use at index.Results: Of 6,337 matched pairs, mean age was 73.3 years and 47.7% of patients were female. Patients with rHK compared to nonHK had higher rates of CV outcomes, including MACE+ (N = 5,258, HR=1.53 95% CI=[1.43, 1.65]) and IP arrhythmia (N = 5,485, 1.94 [1.74, 2.16]) (all p<0.001, Figure 1). Results were consistent in the RAASi subgroup (MACE+: 1.46 [1.31, 1.63]; IP arrhythmia: 1.84 [1.57, 2.16], both p<0.001). Patients with rHK also had higher rates of mortality (Overall: N = 6,337; 1.29 [1.20, 1.38]; RAASi subgroup: 1.25 [1.11, 1.41], both p<0.001) compared to nonHK controls.Conclusions: This study demonstrates that patients with CKD and rHK had significantly higher rates of mortality, MACE+, and IP cardiac arrhythmia compared to matched patients with CKD and nonHK.