Objectives: This review summarizes factors relevant for adherence to phosphate-control strategies in dialysis patients, and discusses interventions to overcome related challenges.
Methods: A literature search including the terms "phosphorus", "phosphorus control", "hemo-dialysis", "phosphate binder medications", "phosphorus diet", "adherence", and "nonadherence" was undertaken using PubMed, PsycInfo, CINAHL, and Embase.
Results: Hyperphosphatemia is associated with cardiovascular and all-cause mortality in dialysis patients. Management of hyperphosphatemia depends on phosphate binder medication therapy, a low-phosphorus diet, and dialysis. Phosphate binder therapy is associated with a survival benefit. Dietary restriction is complex because of the need to maintain adequate protein intake and, alone, is insufficient for phosphorus control. Similarly, conventional hemodialysis alone is insufficient for phosphorus control due to the kinetics of dialytic phosphorus removal. Thus, all three treatment approaches are important contributors, with dietary restriction and dialysis as adjuncts to the requisite phosphate binder therapy. Phosphate-control adherence rates are suboptimal and are influenced directly by patient, provider, and phosphorus-control strategy-related factors. Psychosocial factors have been implicated as influential "drivers" of adherence behaviors in dialysis patients, and factors based on self-motivation associate directly with adherence behavior. Higher-risk subgroups of nonadherent patients include younger dialysis patients and non-whites. Provider attitudes may be important - yet unaddressed - determinants of adherence behaviors of dialysis patients.
Conclusion: Adherence to phosphate binders, low-phosphorus diet, and dialysis prescription is suboptimal. Multicomponent strategies that concurrently address therapy-related factors such as side effects, patient factors targeting self-motivation, and provider factors to improve attitudes and delivery of culturally sensitive care show the most promise for long-term control of phosphorus levels. Moreover, it will be important to identify patients at highest risk for lack of control, and for programs to be ready to deliver flexible person-centered strategies through training and dedicated resources to align with the needs of all patients.
Keywords: adherence; dialysis; hyperphosphatemia; low-phosphorus diet; phosphorus binders.