#3165 ASSOCIATION BETWEEN CKD-MBD AND MORTALITY IN OLDER PATIENTS WITH ADVANCED CKD – RESULTS FROM THE EQUAL STUDY

Abstract

Abstract Background and Aims Chronic Kidney Disease - Mineral and Bone Disorder (CKD-MBD) is a common complication of CKD, associated with higher mortality in dialysis patients. Its impact in non-dialysis patients remains mostly unknown. We investigate the associations between parathyroid hormone (PTH), phosphate, and calcium (and their interactions) and all-cause, cardiovascular (CV), and non-CV mortality in older non-dialysis patients with advanced CKD. Method We used data from the EQUAL study, which included patients aged ≥65 with eGFR ≤20 ml/min/1.73m2 from six European countries. Cox models were used to assess the association between baseline and time-dependent CKD-MBD biomarkers and all-cause, CV, and non-CV mortality. Models were sequentially adjusted for other mineral biomarkers, age, sex, country, eGFR, albumin, BMI, comorbidities and medications. Effect modification between biomarkers was also assessed. Results In 1294 patients, the prevalence of CKD-MBD at baseline was 94%. Both PTH (aHR 1.12, 95%CI 1.03-1.23, p 0.01) and phosphate (aHR 1.35, 95%CI 1.00-1.84, p 0.05), but not calcium (aHR 1.11, 95%CI 0.57-2.17, p 0.76), were associated with all-cause mortality. Calcium was not independently associated with mortality, but modified the effect of phosphate, with the highest mortality risk found in patients with both hypercalcemia and hyperphosphatemia. PTH level was associated with CV mortality, but not with non-CV mortality, whereas phosphate was associated with both CV and non-CV mortality. Conclusion CKD-MBD is very common in older non-dialysis patients with advanced CKD. PTH and phosphate are independently associated with all-cause mortality in this population. While PTH level is only associated with CV mortality, phosphate seems to be associated with both CV and non-CV mortality.