Association between phosphate binder pill burden and mortality risk in patients on maintenance hemodialysis: a single-center cohort study with 7-year follow-up of 513 patients.

Background: Dialysis patients often take multiple oral medications, leading to a high pill burden. Phosphate binders (PBs) account for a large proportion of this daily pill burden (DPB). The relationship between DPB and mortality risk remains unclear, and we hypothesized that this relationship might be influenced by the proportion of PBs to all medications.

Methods: We divided DPB into those derived from PBs and non-PB drugs and analyzed the association with mortality risk over a 7-year period in 513 chronic hemodialysis patients using a baseline model.

Results: The median (interquartile range) DPB from all drugs was 15.8 (11.2-21.0) pills/day/patient, and the median ratio of PB pills to all drug pills was 29.3 (13.7-45.9)% at baseline. During a median observation period of 5.2 years, 161 patients (31.4%) died. Kaplan-Meier analysis showed no significant difference in all-cause mortality between PB users and non-users. However, a significant survival advantage was observed in the highest tertile of DPB from PBs compared to the lowest tertile. Conversely, the highest tertile of DPB from non-PB drugs was associated with worse survival. Consequently, the highest tertile of the ratio of PBs to all pills was associated with better survival. This association remained significant even after adjusting for patient characteristics in the Cox proportional hazards model. However, when serum nutritional parameters were included as covariates, the significant association disappeared.

Conclusions: Dialysis patients prescribed a higher rate of PB pills to all medications exhibited a lower mortality risk, possibly due to their better nutritional status.