Oral Presentation ANZBMS-MEPSA-ANZORS 2022

Patients on dialysis are at lower risk for mortality when treated with non-calcium-based phosphate binders. (#23)

Grahame J Elder 1 2 3 , Tuan V Nguyen 4 5 , Thao P Ho-Le 5 , Jacqueline R Center 3 6
  1. Department of Renal Medicine, Westmead Hospital, Sydney, NSW, Australia
  2. Medical faculty, University of Notre Dame, Sydney, NSW , Australia
  3. Skeletal Diseases Program, Garvan Institute of Medical Research, Sydney, NSW, Australia
  4. School of Biomedical Engineering and Centre for Health Technologies , University of Technology Sydney, Sydney, NSW, Australia
  5. School of Population Health, UNSW Medicine, Sydney, NSW, Australia
  6. St Vincent’s Medical School, UNSW , Sydney, NSW, Australia

Background: Most patients on dialysis take oral calcium-based phosphate binders because elevated serum phosphate is associated with increased cardiovascular risk and mortality. More recently, some patients changed to newer, non calcium-based binders, sevelamer hydrochloride and lanthanum carbonate. This study tested the hypothesis that the progressive displacement of calcium-based binders is associated with reduced all-cause mortality.

 Methods: The study utilised the Australian New Zealand Dialysis and Transplant Registry (ANZDATA) and included all patients ³18 years commencing dialysis in Australia from 1/2005, ending 12/2013. ANZDATA was linked to the Pharmaceutical Benefits Scheme. Data concerning demographic, anthropometric, comorbidities, biochemistry, mortality and drug treatments were collected. The outcome variable was the incidence of mortality during follow-up. The exposure variables were medication use classified into 2 major groups; sevelamer or lanthanum and calcium-based phosphate binders. A mixed-effects Cox's proportional hazards model was used to assess the association between medication use and time to mortality. Propensity score matching was applied to all analyses to deal with potential selection bias on drug treatment.

Results: The study included 7660 women and 12018 men with mean entry ages of 60.5 (15.9) and 62.0 (15.5) years respectively (p<0.001). Median follow-up was 32 (3-120) months, with death occurring in 34.3% of women (106.3/1000 person-years) and 35.1% of men (112.1 per 1000 person-years). Relative to calcium-based phosphate binders, use of the non calcium-based binders was associated with a 62% lower mortality risk (hazard ratio [HR] 0.38; 95% confidence interval [CI] 0.35-0.41) after adjusting for gender, age, comorbidities, and drugs that may influence survival.

Conclusions: For patients on dialysis, non calcium-based phosphate binder use was associated with markedly reduced mortality when compared to calcium-based binders. These results support the concept that positive calcium balance predisposes to increased mortality and support the use of non calcium-based phosphate binders in patient management.