MO808: Indoxyl-Sulphate and Cresyl Sulphate are Respectively Linked to Calcium-Phosphate Metabolism Variables and to Cardiovascular Morbidity in Hemodialysed Patients

BACKGROUND AND AIMS Indoxyl sulphate (IS) and Cresyl sulphate (CS) are uremic toxins generated by the intestinal amino acid catabolism. Blood levels of these toxins increase in patients with CKD and are linked to cardiovascular events. Therefore, we studied the relationship between serum levels of free IS and CS and divalent ion metabolism variables and cardiovascular morbidity (stroke, heart failure, angor and myocardial infarction) in 139 haemodialysis patients (age 68 + 13 years, weight 65 + 13 kg, dialysis vintage 69 + 71 months). METHOD We divided patients according to tertiles of free serum IS and CS. RESULTS Patients in the highest tertile of serum free IS showed shorter dialysis vintage and higher body weight gain between dialysis sessions than patients in the other two tertiles. Patients in the highest tertile of IS showed lower body weight and serum concentrations of alkaline phosphatase, 1,25(OH)2D and PTH compared with the lowest tertile. Serum PTH was also measured during 2 years after the baseline; it was higher in patients in the lowest than those in the highest tertile of serum free IS. No relationships of serum free CS concentrations with phosphate and calcium metabolism variables were observed. Kaplan–Meier survival analysis shows an increased cardiovascular morbidity in patients in the CS highest tertile (blue line in the figure) compared with those in the lowest and middle tertiles taken together (red line; P = 0.01). This association was not found considering IS tertiles. CONCLUSION Our findings suggest that serum free IS may be associated with PTH and 1,25(OH)2D secretion, whereas free PCS may predict cardiovascular risk in haemodialysis patients. A point for future investigation could be the relationship between IS and adynamic bone disease.