Objectives: Hyperkalemia is a common and clinically significant electrolyte disorder in patients with chronic kidney disease (CKD). Although pharmacologic treatment is frequently initiated, long-term potassium control and maintenance of renin–angiotensin–aldosterone system inhibitor (RAASi) therapy remain challenging. This study evaluated treatment patterns, safety outcomes, RAASi utilization, and potassium variability among patients with hyperkalemia who were followed for at least 1 year. Methods: We conducted a multicenter retrospective observational study across three tertiary hospitals between October 2015 and September 2024. Adult CKD patients with at least one serum potassium ≥5.5 mmol/L who received calcium polystyrene sulfonate(CPS) for ≥180 days were included (n=3,094). Treatment patterns, duration of potassium-lowering therapy, adverse events, and RAASi modifications were assessed. Potassium variability was stratified into quartiles based on coefficient of variation, and RAASi exposure duration was compared across groups. Results: Among patients diagnosed with hyperkalemia, 70.8% received pharmacologic treatment. Despite frequent use, the mean annual duration of CPS therapy was 61 days, indicating limited long-term maintenance. Gastrointestinal (GI) adverse events were observed in 82.0% of CPS users compared with 61.3% in non-users. Laxative prescriptions were required in 45.5% of CPS-treated patients. Following hyperkalemia onset, RAASi therapy was discontinued in 27.4% of patients and dose-reduced by ≥25% in 19.8%, resulting in a total of 47.2% experiencing RAASi interruption or significant dose reduction. Higher potassium variability was associated with shorter RAASi treatment duration. Patients in the lowest variability quartile (CV1) maintained RAASi therapy for a mean of 248 days, whereas those in the highest variability quartile (CV4) maintained therapy for only 124 days. Conclusion: Although pharmacologic treatment for hyperkalemia is commonly initiated, long-term maintenance remains suboptimal. CPS use is associated with substantial gastrointestinal adverse events. Hyperkalemia frequently leads to RAASi discontinuation or dose reduction. These findings highlight for more tolerable and sustainable potassium-lowering strategies to optimize the cardio-renal benefit RAASi in high-risk patients.