Long-term effects of patiromer for hyperkalaemia treatment in patients with mild heart failure and diabetic nephropathy on angiotensin-converting enzymes/angiotensin receptor blockers: results from AMETHYST-DN.

AIMS:Chronic kidney disease (CKD) in heart failure (HF) increases the risk of hyperkalaemia (HK), limiting angiotensin-converting enzyme inhibitor (ACE-I) or angiotensin receptor blocker (ARB) use. Patiromer is a sodium-free, non-absorbed potassium binder approved for HK treatment. We retrospectively evaluated patiromer's long-term safety and efficacy in HF patients from AMETHYST-DN. METHODS AND RESULTS:Patients with Type 2 diabetes, CKD, and HK [baseline serum potassium >5.0-5.5 mmol/L (mild) or >5.5-<6.0 mmol/L (moderate)], with or without HF (New York Heart Association Class I and II, by investigator judgement), on ACE-I/ARB, were randomized to patiromer 8.4-33.6 g to start, divided twice daily. Overall, 105/304 (35%) patients had HF (75%, Class II). Mean (standard deviation) ejection fraction (EF) was 44.9% (8.2) (n = 81) in patients with HF; 26 had EF ≤40%. In HF patients, mean serum potassium decreased by Day 3 through Week 52. At Week 4, estimated mean (95% confidence interval) change in serum potassium was -0.64 mmol/L (-0.72, -0.55) in mild and -0.97 mmol/L (-1.14, -0.80) in moderate HK (both P < 0.0001). Most HF patients with mild (>88%) and moderate (≥73%) HK had normokalaemia at each visit from Weeks 12 to 52. Three HF patients were withdrawn because of high (n = 1) or low (n = 2) serum potassium. The most common patiromer-related adverse event was hypomagnesaemia (8.6%). CONCLUSIONS:In patients with a clinical diagnosis of HF, diabetes, CKD, and HK on ACE-I/ARB, patiromer was well tolerated and effective for HK treatment over 52 weeks.