A Systematic Review Of The Prevalence And Determinants Of Nonadherence To Phosphate Binding Medication In Patients With End-stage Renal Disease

Christina Karamanidou; Jane Clatworthy; John Weinman; Rob Horne


BMC Nephrology 

In This Article

Abstract and Background

Background: Cardiovascular events are the leading cause of death in end stage renal disease (ESRD). Adherence to phosphate binding medication plays a vital role in reducing serum phosphorus and associated cardiovascular risk. This poses a challenge for patients as the regimen is often complex and there may be no noticeable impact of adherence on symptoms. There is a need to establish the level of nonadherence to phosphate binding medication in renal dialysis patients and identify the factors associated with it.
Methods: The online databases PsycINFO, Medline, Embase and CINAHL were searched for quantitative studies exploring predictors of nonadherence to phosphate binding medication in ESRD. Rates and predictors of nonadherence were extracted from the papers.
Results: Thirty four studies met the inclusion criteria. There was wide variation in reported rates of non-adherence (22–74% patients nonadherent, mean 51%). This can be partially attributed to differences in the way adherence has been defined and measured. Demographic and clinical predictors of nonadherence were most frequently assessed but only younger age was consistently associated with nonadherence. In contrast psychosocial variables (e.g. patients' beliefs about medication, social support, personality characteristics) were less frequently assessed but were more likely to be associated with nonadherence.
Conclusion: Nonadherence to phosphate binding medication appears to be prevalent in ESRD. Several potentially modifiable psychosocial factors were identified as predictors of nonadherence. There is a need for further, high-quality research to explore these factors in more detail, with the aim of informing the design of an intervention to facilitate adherence.

Cardiovascular events constitute the leading cause of death in dialysis patients, accounting for nearly half of all deaths.[1] The increased incidence of cardiac disease in patients with end-stage renal disease (ESRD) has been associated with hyperphosphatemia and more specifically an elevated Calcium × Phosphate product,[2] making phosphate control an important goal of treatment. Three strategies help to control serum phosphate in ESRD: dialysis, diet restrictions and phosphate binding medication.

Adherence to phosphate binding medication may be a particular challenge for dialysis patients, due to complex treatment regimens that may have no noticeable effect on symptoms. Many patients on dialysis are nonadherent with phosphate binding medication[3] but the extent of the problem and the reasons for it are poorly understood.

There is a current emphasis in the literature on the importance of facilitating adherence to medication in chronic illnesses.[4,5,6] In order to develop a theory-based intervention to optimise adherence to phosphate binding medication, there is a need to first understand the factors associated with nonadherence that could be addressed. Previous reviews of predictors of adherence in ESRD have tended to focus on other aspects of the regime (e.g. diet and fluid restrictions, dialysis attendance)[7,8,9,10] and have not used comprehensive systematic search strategies.[7,8,11] This is the first paper to systematically search and review the literature specifically relating to adherence to phosphate binding medication.

The aims of this review were to assess the prevalence of nonadherence to phosphate binding medication in patients with ESRD and to identify factors associated with low adherence.


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