Poor drug tolerability may be a reason why more than half of dialysis patients, on average, do not adhere to phosphate binder medication. With the range of available phosphate binders likely to expand in the next year, physicians may be able to improve adherence by selecting more appropriate binders for their patients.
A recent paper by Wang et al. identified poor toleration of side-effects as a major reason for discontinuation of phosphate binder treatment. In this study, 30,933 patient records were retrospectively analysed to assess the reasons behind phosphate binder discontinuation. 50% of records did not contain a reason for discontinuation and 27% of discontinuations were due to “lab results”. In this latter category, hypophosphatemia (42%) and hypercalcemia (24%) were the largest attributed causes of discontinuation due to lab results.
11% of discontinuations, the next largest cohort, were due to “patient not tolerating” and further analysis of this group presented some interesting findings. Nearly 48% of these patients discontinued therapy due to gastrointestinal upset and there was noticeable variation in the reasons for discontinuation between specific binders.
Poor tolerability of binders may be a modifiable cause of non-adherence
While discontinuing therapy, and noting this in the patient record, does not equate to non-adherence, there is likely to be a high degree of overlap between the two factors.
Results from a cross-sectional study of approximately 500 patients support this relationship between adherence and tolerability. Almost 15% of patients who were classified as non-adherent in this study (and approximately 6% of those classified as adherent) reported that they always or almost always stopped taking phosphate binders on their own initiative after “feeling worse”.
This intentional non-adherence to therapy may be modifiable with closer consideration of the side effects of particular binders. The Wang et al. study highlights some factors that clinicians may wish to consider when selecting a phosphate binder for an individual patient. Such individualization of treatment could be rewarded with increased medication adherence and, potentially, improved outcomes. This process is also likely to be supported in future by a wider range of available therapy options, with different tolerability profiles.
See also the previous Adherence articles:
March 24th, 2014; Adherence Part 1 – The challenge of non-adherence in hyperphosphatemia
April 24th, 2014; Adherence Part 3 – Why do patients not adhere to therapies?
1. Wang S, Anum EA, Ramakrishnan K, Alfieri T, Braunhofer P, Newsome B. Reasons for phosphate binder discontinuation vary by binder type. J Ren Nutr Off J Counc Ren Nutr Natl Kidney Found. 2014;24(2):105-109. doi:10.1053/j.jrn.2013.11.004.
2. Ketteler M, Biggar PH. Use of phosphate binders in chronic kidney disease: Curr Opin Nephrol Hypertens. 2013;22(4):413-420. doi:10.1097/MNH.0b013e32836214d4.
3. Martins MTS, Silva LF, Kraychete A, et al. Potentially modifiable factors associated with non-adherence to phosphate binder use in patients on hemodialysis. BMC Nephrol. 2013;14(1):208. doi:10.1186/1471-2369-14-208.