#182 A pharmacist intervention with dose optimization of phosphate-binding medication (PIDO-P)in dialysis patients: effects on phosphate, pill burden, and adherence?

Nephrology Dialysis Transplantation, vol. 40

Abstract

Abstract Background and Aims Phosphate-binding medication (PBM) is an essential component of hyperphosphatemia treatment in hemodialysis patients. However, non-adherence to PBM occurs in approximately 50% of dialysis patients and contributes to suboptimal treatment outcomes. Non-adherence to PBM is mainly caused by forgetfulness, a complex treatment scheme, and a high pill burden. It has been suggested that a reduction in PBM pill burden might improve adherence, but this hypothesis has not yet been tested. Our aim was to investigate if the PIDO-P intervention (Pharmacist Intervention with Dose Optimization of Phosphate-binding medication) would reduce mean phosphate levels in hemodialysis patients with hyperphosphatemia and a high PBM pill burden. Method This was a prospective, pre-post intervention study in the Franciscus Gasthuis and Vlietland, a hospital with a 250-patient hemodialysis facility in Rotterdam, the Netherlands. Hemodialysis patients with a mean phosphate level >1.50 mmol/L over the last 3 months and a PBM pill burden of ≥6 sevelamer tablet equivalents were included. The PIDO-P intervention consisted of 3 pharmacist consultations in 3 months. During the first consultation, self-reported adherence to PBM (using MARS-5), and barriers to adherence to PBM (using the Quick Barrier Scan) were assessed. During the second consultation (1–2 weeks later) the pharmacist discussed the identified barriers to adherence and reduced PBM dose according to a predefined treatment algorithm. After 3 months, the pharmacist performed an evaluation consultation, after which the nephrologist resumed hyperphosphatemia treatment (usual care). Primary outcome was mean phosphate level in the 3 months after versus 3 months before start of the intervention. Secondary outcomes were phosphate levels during total follow-up (12 months), percentage of patients within target range for phosphate at 3, 6, and 12 months, and PBM pill burden and self-reported adherence at 3 and 12 months. Statistical analysis was performed with SPSS version 29.0.2, using paired T-tests for phosphate levels and pill burden, and Wilcoxon signed-rank test for self-reported adherence. Results 75 patients were included with a mean age of 65 years, 65.3% of them were male. Patients generally used 12.7 ± 5.0 (mean ± SD) different medications with a total daily pill burden of 22.3 ± 7.7. The main causes of dialysis were hypertension (30.7%) and diabetes (20.0%). The mean phosphate level was 1.99 ± 0.34 mmol/L before start of the intervention versus 2.03 ± 0.37 mmol/L in the 3 months after (P = 0.193, n = 72). The phosphate level remained stable the first 3 months after the intervention (2.04 mmol/L at baseline (BL) vs 2.01 mmol/L at 3 months, P = 0.991) and decreased to 1.86 mmol/L at 12 months (P = 0.025 vs BL, n = 54). The percentage of patients within target range for phosphate increased over time to 26.4% at 12 months (see Fig. 1, P < 0.001 versus BL for all timepoints). PBM pill burden decreased from 8.8 ± 3.1 at BL to 5.8 ± 2.7 after 3 months (P < 0.001), whereafter it increased to approach BL level at 12 months (8.4 ± 3.8, P = 0.261 vs BL). Self-reported adherence to PBM increased from 24 (IQR 22–25) at BL to 24 (IQR 24–25) at 3 months (P = 0.007, n = 61), this higher level of adherence was maintained after 12 months (median 25, IQR 23–25; P = 0.048 versus BL, n = 28). Conclusion Contrary to our expectations, the PIDO-P intervention did not reduce mean phosphate levels. This result might have been caused by a too-low phosphate-binding capacity for the dietary amount of phosphate, as PBM dose was reduced to below 6 sevelamer tablet equivalents. Although phosphate levels did not improve, the percentage of patients within target range for phosphate increased, PBM pill burden was reduced, and self-reported medication adherence increased. Therefore, the PIDO-P intervention seems promising in decreasing PBM pill burden and improving adherence. However, more research is necessary to improve the effectiveness of this intervention, focusing on patients with higher phosphate levels and higher PBM pill burden.

Authors 5

1. Francisca van den Oever Aachen Clinical Pharmacy and Toxicology

   Leiden University · Leiden University Medical Center · Sint Franciscus Gasthuis

   Affiliation as printed

   Franciscus Gasthuis and Vlietland, Clinical Pharmacy, Rotterdam, Netherlands

   Leiden University Medical Centre, Clinical Pharmacy and Toxicology, Leiden, Netherlands

2. Erwin C. Vasbinder

   Sint Franciscus Gasthuis

   Affiliation as printed

   Franciscus Gasthuis and Vlietland, Clinical Pharmacy, Rotterdam, Netherlands

3. Yvonne C. Schrama

   Sint Franciscus Gasthuis

   Affiliation as printed

   Franciscus Gasthuis and Vlietland, Internal Medicine, Rotterdam, Netherlands

4. Teun van Gelder Aachen Clinical Pharmacy and Toxicology

   Leiden University · Leiden University Medical Center

   Affiliation as printed

   Leiden University Medical Centre, Clinical Pharmacy and Toxicology, Leiden, Netherlands

5. Patricia M. L. A. van den Bemt

   University Medical Center Groningen

   Affiliation as printed

   University Medical Centre Groningen, Clinical Pharmacy and Pharmacology, Groningen, Netherlands