Assessing patiromer utilization and associated serum potassium changes in US veterans with prior sodium polystyrene sulfonate exposure.

Untreated chronic hyperkalemia is associated with an increased risk of mortality. Novel potassium binders (e.g., patiromer) are new additions to the clinician's armamentarium. Prior to their approval, clinicians often considered trialing sodium polystyrene sulfonate. The study objective was to assess patiromer utilization and associated changes in serum potassium (K+) in US veterans with prior sodium polystyrene sulfonate exposure. This was a real-world observational study of US veterans with chronic kidney disease and a baseline K+ ≥ 5.1 mEq/L, initiated on patiromer between January 1, 2016, and February 28, 2021. The primary endpoints were patiromer utilization (dispensations and treatment courses), and K+ change at 30-, 91-, and 182-day follow-up (FU) intervals. Patiromer utilization was described using Kaplan-Meier probabilities and the proportion of days covered. Descriptive changes in population average K+ were obtained from a pre-post design using single-arm within-patient pre-post lab pairs and paired t tests. Two hundred five veterans met the study criteria. We observed an average of 1.25 (95% CI, 1.19-1.31) treatment courses and a median treatment duration of 64 days. Fifty veterans (24.4%) had >1 course, and 17.6% of patients remained on their initial patiromer treatment course until the end of the 180-day FU. The mean K+ value was 5.73 mEq/L (5.66-5.79) at baseline, 4.95 mEq/L (95% CI, 4.86-5.05) at the 30-day interval, 4.93 mEq/L (95% CI, 4.84-5.03) at the 91-day interval, and 4.9 mEq/L (95% CI, 4.8-4.99) at the 182-day interval. Novel potassium binders (e.g., patiromer) are newer chronic hyperkalemia management tools for clinicians. The average population K+ decreased to <5.1 mEq/L at all follow-up intervals. Patiromer appeared to be well tolerated with nearly 18% of patients remaining on their initial treatment course during the entire 180-day FU period. The median treatment duration was 64 days and approximately 24% of patients initiated a second course during FU.

Real-world evaluation of patiromer utilization and its effects on serum potassium in veterans with end stage kidney disease.

Hyperkalemia (serum potassium [K+] ≥5.1) is life-threatening in patients diagnosed with end stage kidney disease (ESKD). Patiromer is approved for the treatment of hyperkalemia, although its role in hyperkalemic patients with ESKD is not well understood. This study describes real-world patiromer utilization in an ESKD population and its corresponding association with serum K+ level changes. The study population was comprised of US veterans with an outpatient dispensing of patiromer and 2 or more International Classification of Diseases diagnostic codes for ESKD. A treatment course of patiromer was defined by serial dispensing events without a 30-day gap. Patiromer utilization was described by duration, average dose, persistence, and proportion of days covered during patiromer course. Mean serum K+ values were described for baseline and 3 follow-up intervals during the 180-day follow-up period. There were 458 patients with ESKD included in the study. On average, patients had 1.24 (95% CI: 1.20-1.29) patiromer courses. Half of the population discontinued their first patiromer course within 30 days, while approximately 10% of patients remained persistent at the end of the 180-day period and 102 (22.3%) patients started a second course during the 180-day follow up period. Average serum K+ concentrations during baseline and the 3 evaluation intervals during the 180-day follow-up were 5.91 mEq/L (5.85-5.97), 4.94 mEq/L (4.86-5.03), 4.89 mEq/L (4.8-4.98) and 4.88 mEq/L (4.8-4.96). Few patients remained persistent on their initial course of patiromer at the end of follow-up, but approximately 20% of patients initiated a second treatment episode after a 30-day gap in treatment during the 180-day follow-up period. Nonetheless, average serum K+ in ESKD patients were sustainably reduced by approximately 1 mEq/L during follow-up.

Justification for initiating patiromer when restricted by prior authorization and clinical guidance in a US health care system.

BACKGROUND: In the Veterans Health Administration, patiromer is a formulary medication restricted by prior authorization and criteria-for-use (CFU). Historically, patiromer approval was restricted by step therapy, requiring prescribers to trial sodium polystyrene sulfonate (SPS). OBJECTIVE: To describe clinical scenarios leading to patiromer initiation by characterizing patient experience with primary hyperkalemia treatment modalities, especially SPS. METHODS: All veterans who initiated patiromer between January 1, 2016, and February 28, 2021, with chronic kidney disease and dispensed SPS during the 3 months preceding patiromer were included. A structured chart-review process was used to abstract prior authorization drug request notes to characterize patiromer approval and patient experience with primary pharmacotherapy. Results were reported with descriptive frequencies and proportions. RESULTS: Three hundred thirty-one veterans met inclusion criteria. Primary justification for patiromer initiation included continuation of patiromer initiated outside the Veterans Health Administration or during inpatient stay (5.7%) and SPS inventory shortage (25.4%). CFU justification was mentioned in 83.7% of notes and, among those with CFU justification, SPS treatment was documented in 68.7%. Clinician statements indicating that SPS was ineffective occurred in 65 (41.7%) and statements of safety concerns (either observed or potential) in 37 (23.7%) veterans. CONCLUSIONS: Patiromer approval is multifactorial, and clinicians often opted to avoid long-term SPS use because of safety concerns, lack of consistent availability, and concerns about its appropriateness for longterm hyperkalemia management. DISCLOSURES: Drs Patel and Sauer received funding from Otsuka Canada Pharmaceutical Inc. to study the use of patiromer in the VHA. This material is the result of work supported with resources and the use of facilities at the VA Salt Lake City Health Care System. The views expressed in this manuscript are those of the authors and do not necessarily reflect the position or policy of the Department of Veterans Affairs or the US government. Drs Qualls and Pinnell are supported by the VA Advanced Fellowship Program in Medical Informatics with the Office of Academic Affiliations. This work was funded through a partnered research mechanism. Otsuka Canada Pharmaceutical Inc. was not involved in development or review of this manuscript.