P1433VALIDATION OF A SERUM CALCIFICATION PROPENSITY TEST FOR THE PREDICTION OF ALL-CAUSE MORTALITY AMONG DIALYSIS PATIENTS

Abstract Background and Aims Vascular calcification as cause of vascular stiffness is a major contributor to the high cardiac burden among stage 5 chronic kidney disease dialysis (CKD5HD) patients. Early identification of patients with high calcification propensity is crucial for proper risk stratification and management of these patients. Recently, a novel in vitro test (T50-test) was developed which determines calcification propensity of human serum and predicts mortality among ND-CKD (non-dialysis chronic kidney disease) patients, kidney transplant recipients and CKD5HD patients suffering from secondary hyperparathyroidism. We now evaluated whether these results can be confirmed in an unselected cohort of CKD5HD patients and can be used in the future for improving care of these patients. Method This prospective clinical study included 776 incident and prevalent hemodialysis patients from 8 Fresenius Medical Care NephroCare centers in Cataluña (Spain). T50 was determined at Calciscon AG, all other clinical data were retrieved from the European Clinical Database (EuCliD®). After their baseline T50 measurement, patients were followed for two years for the occurrence of the primary endpoint all-cause mortality. The association between T50 and all-cause mortality was examined by using proportional subdistribution hazards regression modelling accounting for kidney transplantation as competing event. In sensitivity analyses we adjusted for age, sex, vascular access (fistula/graft, catheter), treatment modality (HD, HDF), Charlson comorbidity index and dialysis vintage. Results Mean age of the study population was 72.2 years and 63.8% were male. 42.5% had diabetes and 55.0% past history of cardiovascular disease. Mean T50 was 283.4 min among the total cohort. During follow-up, 185 (23.8%) patients died. Patients who reached the endpoint had a significantly lower T50 at baseline as compared to those who survived during follow-up (269.6 vs 287.7 min, p = 0.001). A cross-validated model (mean c statistic: 0.5767) identified T50 as a linear predictor of all-cause-mortality (subdistribution hazard ratio (per min): 0.9957, 95% CI [0.9933;0.9981]). T50 remained a significant predictor of all-cause mortality after adjusting for relevant confounding in sensitivity analyses. Conclusion In this prospective study, we confirmed that T50 is an independent predictor of all-cause mortality among a large unselected cohort of hemodialysis patients. T50 may be used to identify pa