RESUMO
BACKGROUND: Dialysate purity contributes to the inflammatory response that afflicts hemodialysis patients. OBJECTIVES: To compare the clinical and laboratory effects of using ultrapure water produced by a water treatment system including two reverse osmosis (RO) units in series, with a system that also includes an ultrapure filter (UPF). METHODS: We performed a retrospective study in 193 hemodialysis patients during two periods: period A (no UPF, 6 months) and period B (same patients, with addition of UPF, 18 months), and a historical cohort of patients treated in the same dialysis unit 2 years earlier, which served as a control group. RESULTS: Mean C-reactive protein, serum albumin and systolic blood pressure worsened in period B compared to period A and in the controls. CONCLUSIONS: A double RO system to produce ultrapure water is not inferior to the use of ultrapure filters.