POS-791 EVALUATION OF EFFECTIVENESS OF AN ALTERNATIVE PRESCRIPTION PATTERN OF CINACALCET FOR BETTER CONTROL OF PARATHYROID HORMONE LEVELS IN HEMODIALYSIS PATIENTS

Abstract

Due to the high pill burden, non-adherence (NA) to medications is highly prevalent among hemodialysis patients. NA to Cinacalcet in particular, poses a significant challenge in controlling parathyroid hormone (PTH) levels. Perhaps an effective way to improve adherence to Cinacalcet is to reduce the frequency of administration. There is limited knowledge of the effectiveness of controlling PTH level with three times per week (TIW) Cinacalcet compared with conventional daily dosing. The objective of this longitudinal retrospective single-center observational study was to evaluate the effectiveness of three times a week (TIW) Cinacalcet dosing compared with conventional daily dosing (DD) in subsequent levels of Parathyroid Hormone (PTH) in hemodialysis patients. All adult hemodialysis patients on Cinacalcet for secondary hyperparathyroidism (sHPT) for more than six months were selected. Patients who did not have any adherence issues continued oral Cinacalcet daily (QID) while patients who were suspected to be NA to Cinacalcet or suffered from intolerance were given oral Cinacalcet three times a week (TIW) on dialysis days under direct observation of the dialysis nurse. The dose of Cinacalcet was determined by the physician to maintain PTH levels within 130 - 600 pg/ml as per KDIGO guidelines. PTH levels were monitored every other month and the dose was titrated accordingly. All these patients also received intravenous alfacalcidol and phosphate binders at the discretion of the physician to maintain adjusted calcium and phosphate levels within the KDIGO recommendations. The primary endpoint of the study was to assess whether TIW dosing was more effective than QID dosing in terms of maintaining PTH levels within the KDIGO recommended range. Data regarding patients’ acceptability, tolerability, hypocalcemia, and required weekly cumulative Cinacalcet dose were also collected. Patients were followed up for 12 months. There were 40 patients in the QID group and 52 in the TIW group. All participants in the TIW group reported acceptability and improved tolerability and hence better adherence to the dosing regimen. Some in the TIW model even reported perceived improvement in their commitment to adherence. In terms of effectiveness, the TIW group showed better monthly PTH trends compared to the QID group as illustrated by the graph below. This appeared to be sustained over the 12 months follow up period. Concomitantly, the required cumulative dose of Cinacalcet per week was also much less in the TIW group (270 mg/week) compared to the QID group (420 mg/week) suggesting a significant healthcare cost saving in long run. While there were cases of hypocalcemia observed in the QID group no such events were noticed in the TIW group. Taken together, the results of our study confirm that patients on the TID model of prescription were able to achieve and sustain the PTH levels consistent with KDIGO recommendation with much lower cumulative Cinacalcet dose with consequent lower healthcare costs. Nevertheless, we do agree that this alternative model of prescription (TIW) needs to be further validated in a prospective study before drawing stronger conclusions.