[Phosphorus binders: preferences of patients on haemodialysis and its impact on treatment compliance and phosphorus control].

INTRODUCTION

Non-adherence to phosphate binding (PB) medication may play a role in the difficulty in achieving the targets for phosphorus. We have a wide armamentarium of PB but preferences of patients are poorly understood.

OBJECTIVE

to study the patients' preferences and beliefs regarding PB and their influence on adherence and serum phosphate.

METHODS

A cross-sectional cohort study was performed. A total of 121 hemodialysis patients answered a specific questionnaire in which they were questioned about adherence, the type of PB they preferred and the reasons for their choice. All patients questioned tasted two or three PB. The consequence of non-adherence to PB was estimated indirectly by determination of serum phosphorus.

RESULTS

Specific noncompliance with PB medication was recognized by 21.4% of patients. Patients non-adherent specifically to PB were more likely to have P levels >5.5 mg/dl (χ(2): 4.7; 95% CI 1.07-6.5; p = 0.03). Paradoxically, patients non-adherent showed greater knowledge of the use (χ(2): 17.3; 95% CI -2.2-10.1; p <0.0001) and importance of the drug (χ(2): 10.4; 95% CI -1.5-6.6; p = 0.001). The percentage of patients prescribed binders they did not like was 54.5%. Patients who were taking PB they did not like had a greater risk of having P levels >5.5 mg/dl) (χ(2): 13.3; 95% CI -1.1-1.5; p = 0.0001). Calcium acetate was the preferred PB in 47.1% of patients, lanthanum carbonate in 40%, sevelamer in 20.6% and aluminum hydroxide in 19.4%. The reasons claimed by patients for their negative ratings of PB were the type of dosage form, the taste, the number of tablets and gastric intolerance. Gastric intolerance and bad taste were more frequent in aluminum hydroxide patients (19.4% and 22.2%, respectively). Sevelamer received complaints about its dosage form because the tablets were too large and a large number of tablets were required (27.2%). 17.7% of patient who were taking lanthanum carbonate did not like the chewable tablets.

CONCLUSION

patients who were taking binders that they did not like had worse serum P levels and were prescribed higher doses of binders. Knowing patients' preferences about the drugs prescribed may be a key factor in achieving adequate adherence to treatment.