#3664 EVALUATION OF THE INTRODUCTION OF NOVEL POTASSIUM BINDERS IN ROUTINE CARE: THE STOCKHOLM CREATININE MEASUREMENTS (SCREAM) PROJECT
Authors: González-Ortiz Ailema , Bosi Alessandro , Fu Edouard , Pérez-Guillé Beatriz E , Evans Marie , Clase Catherine M , Zoccali Carmine , Carrero Juan Jesus 
Published: June 2023

Abstract

Background and Aims
The pharmacological management of hyperkalemia has traditionally considered sodium polystyrene sulfonate (SPS) and, since late 2018, the novel potassium (K+) binders Patiromer and Sodium Zirconium Cyclosilicate (SZC). This study evaluated their patterns of use, duration of treatment and relative effectiveness in reducing plasma K+ levels in Stockholm´s contemporary routine care.

Method
Observational study of all adults who newly-filled a prescription for SPS, Patiromer or SZC during 2019–2021 in Stockholm, Sweden. Sweden offers universal healthcare and covers the cost of prescribed medications. We described patient characteristics of new initiators, including their comorbidities, medication use, eGFR and pre-treatment plasma K+ levels. We then quantified treatment duration by evaluating all subsequent dispensations. Lastly, we compared their relative efficacy by evaluating post-treatment K+ during the following 60 days through multivariable logistic regression. Because the frequency and pattern of K+ monitoring differed per patient, we considered the K+ test closest to the end of 15-day intervals. Then, we estimated odds ratios and 95% confidence intervals of maintaining normokalemia (K+&lt;5.1 and &lt;5.5 mmol/L) for the novel binders vs SPS.

Results
During 2019–2021, 1879 adults started treatment with SPS, and 147 with novel binders (41 with Patiromer and 106 with SZC). The median K+ at initiation for all three treatments was 5.7 mmol/L. Median eGFR was higher among Patiromer initiators (58 mL/min/1.73 m2) than initiators of SZC (31 mL/min/1.73m2) or SPS (37 mL/min/1.73m2). Patients on SPS stayed mean 61 days on treatment, and 14% filled three or more consecutive prescriptions suggesting chronic use. Patients on novel binders stayed mean 109 days on treatment, and 49% filled three or more prescriptions (Panel A). After 15 days of treatment, mean plasma K+ similarly decreased to 4.6 (4.3-5.1) and 4.8 (4.5-5.2) mmol/L in patients with SPS and novel binders, respectively, and this level was maintained during the 60 days post-treatment (Panel B). 76% of SPS users reached a potassium value &lt;5.1 mmol/L at day 15 versus 67% of patients in the novel binder group (between group difference 9%; 95% CI 0.92-2.57; p-value 0.07; Panel C). Furthermore, the proportion of patients with K+ &lt;5.5 mmol/L at day 15 was 91% for SPS and 85% for novel binders (Panel D). In multivariable logistic regression, the odds ratio for novel binders (vs SPS) in reaching K+ targets (K+ &lt;5.1 mmol/L) after 15 days was 0.68 (95% CI 0.4-1.17) and 0.78 (95% CI 0.42-1.44) after 30 days.

Conclusion
We observe modest use of novel K+ binders in Stockholm's contemporary practice, with longer treatment lengths than SPS. Both SPS and novel binders showed similar efficacy in achieving normal potassium values during the first 15 days of treatment and subsequent 2 months.