Randomised, blinded, cross-over evaluation of the palatability of and preference for different potassium binders in participants with chronic hyperkalaemia in the USA, Canada and Europe: the APPETIZE study

OBJECTIVES: Traditional potassium (K⁺) binders for treating hyperkalaemia are unpalatable and poorly tolerated. Newer K⁺ binders are reportedly better tolerated; however, no published data describe their palatability, a determinant of long-term adherence. This study evaluated the palatability of and preference for three K⁺ binders: sodium and calcium polystyrene sulfonate (S/CPS), sodium zirconium cyclosilicate (SZC) and calcium patiromer sorbitex (patiromer). DESIGN: Phase 4, randomised, participant-blinded, cross-over study. Participants were randomised to one of six taste sequences and, using a 'sip and spit' approach, tasted each K⁺ binder before completing a survey. SETTING: 17 centres across the USA, Canada and European Union. PARTICIPANTS: 144 participants with chronic kidney disease, hyperkalaemia and no recent use of K⁺ binders. MAIN OUTCOME MEASURES: For the primary (USA) and key secondary (Canada and European Union) endpoints, participants rated palatability attributes (taste, texture, smell and mouthfeel) and willingness to take each K⁺ binder on a scale of 0-10 (rational evaluation). Feelings about each attribute, and the idea of taking the product once daily, were evaluated using a non-verbal, visual measure of emotional response. Finally, participants ranked the K⁺ binders according to palatability. RESULTS: In each region, SZC and patiromer outperformed S/CPS on overall palatability (a composite of taste, texture, smell and mouthfeel), based on rational evaluation and emotional response. Taking the product once daily was more appealing for SZC and patiromer, creating greater receptivity than the idea of taking S/CPS. The emotional response to mouthfeel had the strongest influence on feelings about taking each product. In each region, a numerically greater proportion of participants ranked SZC as the most preferred K⁺ binder versus patiromer or S/CPS. CONCLUSIONS: Preference for more palatable K⁺ binders such as SZC and patiromer may provide an opportunity to improve adherence to long-term treatment of hyperkalaemia. TRIAL REGISTRATION NUMBER: NCT04566653.