Pill burden, adherence, hyperphosphatemia, and quality of life in maintenance dialysis patients

Abstract

Background and objectives: Dialysis patients have a high burden of co-existing diseases, poor health-related quality of life (HR-QOL), and are prescribed many medications. There are no data on daily pill burden and its relationship to HR-QOL and adherence to therapy.

Design, setting, participants, & measurements: Two hundred and thirty-three prevalent, chronic dialysis patients from three units in different geographic areas in the United States underwent a single, cross-sectional assessment of total daily pill burden and that from phosphate binders. HR-QOL, adherence to phosphate binders, and serum phosphorus levels were the three main outcome measures studied.

Results: The median daily pill burden was 19; in one-quarter of subjects, it exceeded 25 pills/d. Higher pill burden was independently associated with lower physical component summary scale scores on HR-QOL on both univariate and multivariate analyses. Phosphate binders accounted for about one-half of the daily pill burden; 62% of the participants were nonadherent. There was a modest relationship between pill burden from phosphate binders and adherence and serum phosphorus levels; these associations persisted on multivariate analyses. There was no relationship between adherence and serum phosphorus levels.

Conclusions: The daily pill burden in dialysis patients is one of the highest reported to date in any chronic disease state. Higher pill burden is associated with lower HR-QOL. There are many reasons for uncontrolled serum phosphorus levels; increasing the number of prescribed pills does not seem to improve control and may come at the cost of poorer HR-QOL.

Figures

Figure 1.

Frequency distribution of total pill burden in the study cohort.

Figure 2.

Percentage of pill burden from different classes of medications.

Figure 3.

Distribution of patients by centers, based on adherence to phosphate binders from pill count at the time of the study visit. Subjects were deemed to be adherent if they consumed 80% to 120% of the expected pill count.

Figure 4.

Adherence to phosphate binders in subjects grouped into quintiles of pill burden from phosphate binders.

Figure 5.

Mean serum phosphorus levels in subjects grouped into quintiles of pill burden from phosphate binders.