FP442
CITRATE-ACIDIFIED DIALYSATE IMPROVES THE CALCIFICATION PROPENSITY OF HEMODIALYSIS PATIENTS: A MULTICENTER PROSPECTIVE RANDOMIZED CONTROLLED CROSS-OVER TRIAL Free

INTRODUCTION AND AIMS: The prescription of dialysate calcium concentration (dCa) has been suggested to affect vascular calcification, but evidence is scarce. The use of citrate-acidified dialysate (dCit) may have a beneficial effect on the calcification tendency. The aim of this study was to compare the intradialytic and short-term effects of dCa of 1.50mmol/l (dCa1.50) and dCa of 1.25mmol/l (dCa.25), as well dCit (with a dCa of 1.50 mmol/l) on calcification propensity in serum.

METHODS: Nineteen chronic hemodialysis patients (mean age 66.6 years) from two centers were randomized into a cross-over sequence of dCa1.25 or dCit for one week, the alternate treatment was provided after a washout week with dCa1.50. Calcification propensity of serum was assessed by time-resolved nephelometry where the T₅₀ reflects the transition time between formation of primary and secondary calciprotein particles.

RESULTS: Intradialytic change (Δ) in T₅₀ is increased in dCit (119.6±35.2min) compared to dCa1.25 (76.6±40.9min, p<0.001) and dCa1.50 (62.8±43.9min, p<0.001). ΔT50 was inversely correlated to Δphosphate in all treatments (dCa1.50: r_s=-0.68, p<0.01; dCa1.25: r_s=-0.69, p<0.01; dCit: r=-0.46, p=0.06), and to Δionized calcium in dCa1.25 (r=-0.61, p=0.01), dCitr (r=-0.46, p=0.05) and dCa1.50: r=-0.45, p=0.06). During the treatment week, predialysis T₅₀ increased significantly for dCit (278.5±50.5 to 295.8±55.2min, p=0.001) with a tendency for dCa1.25 (287.6±58.5 to 303.4±57.9min, p=0.07), but not for dCa 1.50 (287.0±65.8 to 297.6±54.9min, p=0.47).

CONCLUSIONS: Calcification propensity, as measured by the change in T₅₀, improved significantly during treatment in dCit compared to dCa1.25 and dCa1.50, with effects potentially lasting beyond the dialysis treatment. Changes in ionized calcium during dialysis may also effect calcification propensity. Long term studies are needed to investigate whether dCit and modifying dCa could have a beneficial effect on patient prognosis and vascular calcification.