Purpose: The long-term effects of patiromer on serum K+ in HFmrEF pts on RAASi were examined in a post-hoc analysis of AMETHYST-DN.
Methods: Pts with CKD, type 2 DM and HK (baseline K+ >5.0–<6.0 mmol/L) were randomized to patiromer starting doses 8.4–33.6 g/d, divided twice daily. Pts with HTN were eligible if uncontrolled at screening (SBP: >130 to =180mmHg; DBP >80 to =110mmHg). Pts remained on RAASi during study treatment. Changes in mean K+ (central lab) from baseline through 52 wks were evaluated in the HFmrEF subgroup.
Results: 46/306 randomized pts had HFmrEF (100% Caucasian, 74% male, 72% =65 yr; mean [SD] EF=44  % and eGFR=42  mL/min/1.73m²). All had HTN (baseline mean BP 154/84 mmHg). K+ was reduced to <5.0 mmol/L at the 1st post-baseline visit (day 3) and through 52 wks (Table). Thirty-three (72%) pts reported =1 adverse event (AE); influenza and worsening of CKD were the 2 most common AEs (5 pts each; none severe). Two pts had K+ <3.5 mmol/L; 1 pt had serum Mg <0.49 mmol/L. Mean (SE) change from baseline to 52 wks was: eGFR, +5 (4) mL/min/1.73m²; SBP/DBP, -21 (4)/-10 (2) mmHg.
Conclusions: These post-hoc results suggest that patiromer allows control of HK in HFmrEF pts on RAASi and require prospective evaluation.