P0877ASSOCIATIONS OF DISORDERS IN BONE MINERAL PARAMETERS WITH MORTALITY IN STAGE 4 AND 5 CKD: INSIGHTS FROM THE PECERA STUDY

Background and Aims Abnormalities of bone mineral parameters are associated with increased mortality in patients on dialysis, but their effects and the optimal range of these biomarkers are less well characterized in non-dialysis chronic kidney disease (CKD). Method PECERA (Collaborative Study Project in Patients with Advanced Chronic Kidney Disease) is a 3-year, multicentre, open-cohort, prospective study carried out in 995 adult patients with CKD stages 4-5 not on dialysis enrolled in 2007-09 from 12 centres in Spain. Associations between levels of serum calcium (corrected for serum albumin), phosphate, and intact parathyroid hormone (iPTH) and all-cause mortality were examined using time-dependent Cox proportional hazards models and penalized splines analysis adjusted by demographics and comorbidities, treatments and biochemical collected at baseline and every 6 months for 3 years. Results After a median follow-up of 30 months (IQR:14-37 months) there were 180 deaths (18%). The association of calcium and phosphate with all-cause mortality was U-shaped (Figure). The serum values associated with the minimum risk of mortality were 9.35 mg/dL for calcium and 3.56 mg/dL for phosphate, being the lowest risk ranges between 7.4 to 10.7 mg/dL and between 2.3 to 4.6 mg/dL for calcium and phosphate, respectively. For iPTH levels, the association was J-shaped, with an increased risk for all-cause mortality at levels > 110 pg/mL. Conclusion As previously reported in dialysis patients, PECERA provided evidence on the association of serum calcium, phosphate and iPTH levels with all-cause mortality in stage 4 and 5 CKD patients, suggesting potential survival benefits of controlling bone mineral parameters in this population. Whereas the ranges of calcium and phosphate associated with the lowest mortality in the study were consistent with the current K-DIGO guidelines, our results suggested that the threshold for considering anti-parathyroid treatment might be lower than is currently recommended.