Purpose: Renin angiotensin aldosterone system inhibitors (RAASi) are indicated in patients (pts) with heart failure with reduced ejection fraction (HFrEF). RAASi increase the risk of hyperkalaemia (HK), particularly in pts with chronic kidney disease (CKD) and/or diabetes, and are often discontinued in HFrEF pts. Patiromer, a nonabsorbed, sodium-free potassium (K+)-binder, was previously shown in the AMETHYST-DN study to lower serum K+ (s-K+) through 52 weeks in pts with HK and diabetic nephropathy on RAASi. In this post-hoc analysis we examined the effects of patiromer on s-K+ in HK patients with HFrEF. Methods: Patients with type-2 diabetes, CKD, and HK (baseline s-K+ >5.0–<6.0 mmol/L) were randomized to patiromer starting doses of 8.4–33.6 g/day, divided twice daily. All pts were receiving RAASi during study treatment. Changes in mean s-K+ from baseline through Week 52 were evaluated in the subgroup with HFrEF (EF =40%). Results: Of 306 randomized pts, 26 had HFrEF (100% Caucasian, 62% male, 69% =65 yr of age, mean [SD] EF: 37 %, mean [SD] eGFR: 43.6 [17.7] mL/min/1.73m2. Mean s-K+ was reduced to <5.0 mmol/L at the first post-baseline visit (day 3, 48 hr after first patiromer dose) through Week 52 and stopping patiromer led to a rise in s-K+ (Table). No pts discontinued due to high s-K+. Patiromer was generally well tolerated, with 17 (65%) pts reporting =1 adverse event (AE) during the study. Mild or moderate gastrointestinal AEs were the most common class (occurring in 2 pts) of patiromer-related AEs, with abdominal discomfort, nausea and vomiting each occurring in 1 pt. No pts had s-K+ <3.5 mmol/L, 1 pt had serum magnesium <1.4 mg/dL (<0.57 mmol/L), and there were no reports of edema. From a baseline mean (SE) of 151.1 (2.0)/90.8 (2.1) mmHg, systolic/diastolic BP decreased by 17.0 (2.2)/ 16.2 (2.3) mmHg at Week 52. Conclusions: Patiromer decreased s-K+ through 52 weeks in HFrEF pts with HK and diabetic nephropathy. These post-hoc results, suggesting that patiromer allows continuous management of HK in HFrEF pts on RAASi, require further prospective evaluation.
Values are mean (SE) in mmol/L.