Effect of Patiromer on Hyperkalemia Recurrence in Older Chronic Kidney Disease Patients Taking RAAS Inhibitors

BACKGROUND: Older people are predisposed to hyperkalemia because of impaired renal function, comorbid conditions, and polypharmacy. Renin-angiotensin-aldosterone system inhibitors (RAASi), which are recommended to treat chronic kidney disease and heart failure augment the risk. Patiromer, a nonabsorbed potassium binder, was shown in the phase 3 OPAL-HK study to decrease serum potassium in patients with chronic kidney disease taking RAASi. We studied the efficacy and safety of patiromer in a prespecified subgroup of patients aged >= 65 years from OPAL-HK. METHODS: Chronic kidney disease patients with mild or moderate-to-severe hyperkalemia received patiromer, initially 8.4 g/d or 16.8 g/d, respectively, for 4 weeks (treatment phase, part A). Eligible patients entered an 8-week randomized withdrawal phase (part B) and continued patiromer or switched to placebo. RESULTS: Mean +/- standard error change in serum potassium from baseline to week 4 of part A (primary endpoint) in patients aged >= 65 years was -1.01 +/- 0.05 mEq/L (P < .001); 97% achieved serum potassium 3.8-<5.1 mEq/L. The serum potassium increase during the first 4 weeks of part B was greater in patients taking placebo than in those taking patiromer (P < .001). Fewer patients taking patiromer (30%) than placebo (92%) developed recurrent hyperkalemia (serum potassium >= 5.1 mEq/L). Mild-to-moderate constipation occurred in 15% (part A) and 7% (part B) of patients aged >= 65 years. Serum potassium < 3.5 mEq/L and serum magnesium < 1.4 mg/dL were infrequent (4% each in patients aged >= 65 years in part A). CONCLUSIONS: Patiromer reduced recurrent hyperkalemia and was well tolerated in older chronic kidney disease patients taking RAASi. (C) 2018 The Authors. Published by Elsevier Inc.