SUN-255 Calcium phosphate product predicts adverse outcomes in chronic kidney disease: novel insight using trajectory analysis

Abstract

In patients with chronic kidney disease (CKD), abnormalities of calcium and phosphorus are common. We aimed to determine whether longitudinal trajectories of serum calcium, phosphate and calcium phosphate product (Ca x P) are associated with the risk of end-stage renal disease (ESRD), acute coronary syndrome (ACS) and all-cause mortality among CKD patients. We conducted a prospective cohort study using data from a 13-year multidisciplinary pre-ESRD care registry. The final study population consisted of 4,237 CKD patients aged 20-90 years between 2003-2015. Individual serum calcium, phosphate, Ca x P trajectories were defined using group-based trajectory modeling in three distinct patterns: low, moderate, and high. Time to ESRD, ACS and death were analyzed by multiple Cox regression. A total of 1,234 ESRD events and 608 deaths occurred during the -14,577.1 person-years of follow-up. Kaplan-Meier curves showed participants with a “high” Ca x P trajectory presented shorter dialysis-free survival, ACS-free survival and overall survival (log-rank test, P < 0.001). Compared to those with a “normal” Ca x P trajectory, the adjusted hazard ratio (HR) (95% confidence interval [CI]) for incidental ESRD was as follows: “moderate ” 4.4 (3.5 to 5.6), “high” 10.5 (8.1, 13.5); the adjusted HR (95% CI) for all-cause mortality was as follows: “moderate” 1.71 (1.49 to 1.96), “high” 2.47 (2.07 to 2.95). We observed a similar association between Ca x P trajectories and incident ESRD, ACS and mortality with regard to age, gender, diabetes, and hypertension.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Figure 1. Trajectories as defined by group-based trajectory modelling (GBTM) of mean Ca, P and Ca x P over time. Figure 2. Kaplan-Meier curves of dialysis-free survival, ACS-free survival and overall survival, according to Ca x P trajectories generated by group-based trajectory modelling (GBTM). Elevated serum Ca x P trajectories are associated with accelerated kidney failure, acute coronary syndrome and all-cause mortality in CKD patients, even after medical control for Ca x P. To maintain long term stable serum level of calcium, phosphate and calcium phosphate product is important for CKD outcome.