Serum phosphorus levels and pill burden are inversely associated with adherence in patients on hemodialysis

Abstract

BackgroundPhosphate binders (PBs) account for about one half of the daily pill burden for US hemodialysis (HD) patients, which may reduce adherence. Adherence can be estimated by the medication possession ratio (MPR), which is defined as the proportion of time a patient had sufficient medication to have taken it as prescribed. Gaps of time between prescription fills lower the patient's MPR. We assessed the association of PB pill burden and adherence (MPR) with phosphorus goal attainment.MethodsUsing pharmacy management program data, HD patients on PB monotherapy were tracked from first PB fill during 1 January 2007–30 June 2011 for 1 year, or until PB change or censoring. Data were assessed with generalized linear models.ResultsWe analyzed 8616 patients. Higher pill burden was associated with lower adherence. Lower adherence tended to be associated with higher mean phosphorus levels and lower percentage of patients with serum phosphorus ≤5.5 mg/dL (P < 0.001). The association between adherence and these clinical outcomes was most pronounced in the lowest and highest pill burden strata (<3, >3–6, >12–15, >15).ConclusionsAdherence, as measured by the MPR, was negatively related to higher pill burden and phosphorus levels and positively related to patients in the phosphorus target range. Within pill burden strata, phosphorus increased and patients in the target range generally decreased with decreasing adherence, suggesting that patients prescribed fewer PB pills are less likely to have treatment gaps, and may be more likely to achieve phosphorus targets.

A Comparison of the Phosphorus Content in Prescription Medications for Hemodialysis Patients in Japan

“…Further, a signiˆcant fall oŠ in adherence to binder therapy might occur as the pill burden increases. 17,18) From these results, prescribing these medications to dialysis patients might be harmful in that they add substantially to an already problematic phosphorus burden. It is possible to determine whether phosphorus is present in a medication by examining its package label that is usually available online from the manufacturer, both branded and generic.…”

Contemporary management of phosphorus retention in chronic kidney disease: a review

“…In a retrospective, observational study by Wang et al, 8616 patients were analyzed based on phosphate binder pill burden, adherence, and serum phosphorus levels among hemodialysis patients. This study revealed adherence, as measured by the medication possession ratio, was negatively related to higher pill burden and phosphorus levels and positively related to patients in the phosphorus target range [69]. We know that Phosphorus is ubiquitous in our daily diet; its absorption is poorly recognized.…”

The Economic Impact of Improving Phosphate Binder Therapy Adherence and Attainment of Guideline Phosphorus Goals in Hemodialysis Patients: a Medicare Cost-Offset Model

“…Analyses from this research team also showed an inverse relationship between pill burden and both medication adherence and percent time in KDOQI phosphorus concentration range (PTR) [10]. In a sample of 8,616 hemodialysis patients, high pill burden was associated with low adherence, and low adherence was associated with higher serum phosphorus concentrations [10].…”

“…Primary treatment with oral phosphate binder therapies offers a limited benefit in achieving target phosphorus concentration due to issues related to their high daily pill burden (averaging 7-10 pills/day) and poor medication adherence. A study conducted by this research team showed a low rate of adherence with phosphate binders reflected by a medication possession ratio (MPR) averaging around 40-50% [10]. Other studies have reported adherence ranging between 21 and 74%, depending on patient population and measurement method [11][12][13][14][15][16].…”

“…In the same study, adherent patients (prescribed 8.2 pills/day) acknowledged taking 92.6% of their daily pills, meaning that the adherent patients, who were prescribed one less pill/day on average versus nonadherent patients, took a greater proportion of prescribed doses than the nonadherent patients (92.6% versus 45.2%) [17]. Analyses from this research team also showed an inverse relationship between pill burden and both medication adherence and percent time in KDOQI phosphorus concentration range (PTR) [10]. In a sample of 8,616 hemodialysis patients, high pill burden was associated with low adherence, and low adherence was associated with higher serum phosphorus concentrations [10].…”