#4787 VITAMIN D AND PARATHYROID HORMONE PREDICT INCIDENT MAJOR ADVERSE CARDIAC EVENTS IN PATIENTS STARTING HAEMODIALYSIS: A REAL-WORLD ANALYSIS

Abstract Background and Aims Despite its advantages, haemodialysis (HD) is associated with increased cardiovascular mortality and morbidity, with some studies reporting 48% higher mortality, within 2 years of starting treatment. HD patients are known to suffer from vitamin D deficiency which has been linked to excess CV mortality and morbidity. We aimed to investigate the prognostic significance of vitamin D in predicting incident Major Adverse Cardiovascular Events (MACE) within 5 years of commencing HD. Method A retrospective cohort study was performed using electronic medical records from a global federated research network from the US (TriNetX). The TriNetX network was searched on 31st January 2023. The cohorts commenced HD post-diagnosis of End-Stage Kidney Disease. Data censoring for MACE was invoked prior to the index event of HD. Vitamin D (25-hydroxyvitamin D and 1,25 dihydroxy Vitamin D) concentrations were the first reported result within 3 months of starting HD. Cohorts were grouped according to biomarker-specific thresholds and 1:1 propensity-score matched for age, gender, and co-morbidities (hypertension, diabetes mellitus and smoking status). Logistical regression produced odds ratios with 95% CI for 5-year MACE. MACE was defined, a priori, as a composite of ischaemic heart disease, angina pectoris, acute myocardial infarction, heart failure, AF, stroke, and all-cause mortality. All statistical analysis was performed on the TriNetX online platform. Results The results are shown below. There was no association between outcome and PTH at 55 pg/ml threshold. Only results that reached statistical significance (p<0.05) are shown. Patients with a 25-OH Vitamin D concentration <24 ng/ml or 1,25-diOH Vitamin D at <35 pg/ml had significantly more events, as shown below. Conclusion Circulating plasma levels of cholecalciferol and calcitriol are predictive of CV outcomes in patients commencing HD; however, the risk profile is different between low levels of active and inactive vitamin D. As the incident HD population are at increased risk of CV mortality and morbidity, cholecalciferol and calcitriol should be included in assessing overall risk.