Dr. David Bushinsky (DB), from University of Rochester Medical Center in Rochester, New York, discusses his abstract for the National Kidney Foundation’s 2016 Spring Clinical Meetings (SCM16), Patiromer Decreases Serum Potassium in Patients on HD, with Dr. Kenar Jhaveri, AJKD Blog Editor.
AJKDblog: Why don’t you tell us a little about your research and abstract being presented at the NKF 2016 Spring Meetings?
DB: The goal of this study was to determine the effect of patiromer on serum potassium (K) in hemodialysis patients. Six hemodialysis patients were admitted to a clinical research center, placed on a controlled diet, and stopped use of all phosphate binders. During the first “pre-treatment” week, subjects were evaluated on the controlled diet and then started on patiromer for the second week. Daily laboratory and 24-hour stools were collected and analyzed.
We found that patiromer reduced the serum K and reduced the number of days that subjects were hyperkalemic. Patiromer removed more K in a week than has been reported by lowering the dialysate K concentration by 1 mEq/L for 3 treatments per week. The medication was well tolerated, no subject discontinued the treatment for an adverse event, and there were no serious adverse events reported.
AJKDblog: Was there an effect on phosphorous and magnesium levels?
DB: As expected, we observed an increase in serum phosphate (P) following discontinuation of P binders. During treatment with patiromer, there was a gradual decrease in serum P. By the end of the patiromer treatment week, the long interdialytic serum P was significantly lower than the corresponding long interdialytic serum P prior to the start of patiromer, having decreased from 7.0 to 6.2 mg/dL (P = 0.04). This is consistent with data from an earlier study in healthy subjects on a controlled diet showing that patiromer decreases urine P, suggesting intestinal P binding in subjects treated with patiromer. Since patiromer exchanges intestinal K for calcium (Ca), it is possible that the released Ca is binding P.
Serum magnesium (Mg) remained in the normal range throughout the study and no subject developed hypomagnesemia. The lowest recorded Mg was 1.3 mEq/L. According to prescribing information for patiromer, Mg levels should be followed in subjects treated with the drug.
AJKDblog: Where do you and your group go from here?
DB: We think this data is very exciting and raises a number of questions about how we routinely perform hemodialysis. As you know, the use of the “standard” 2 K dialysate bath or even a 1 K bath that is not infrequently used is not based on careful study, and neither of these baths have ever been shown to be inherently safe or optimal. Some data even indicate risk of using the lower K bath.
This small study demonstrates a new way to lower K in our hyperkalemic dialysis patients. It makes sense, perhaps, to use a more physiologic K bath, which will induce less shifts in K and use oral patiromer to lower the serum K. We should explore this scenario in a large randomized, multicenter study.
All Spring Clinical Meeting abstracts are available in the May issue of AJKD.