Association of Pre-ESRD Serum Calcium With Post-ESRD Mortality Among Incident ESRD Patients: A Cohort Study

Abstract

Albumin-corrected serum calcium (cSCa) decline at late stages of chronic kidney disease and rise after dialysis initiation. While hypercalcemia is associated with higher mortality in end-stage renal disease (ESRD), there are scarce data on the impact of pre-ESRD cSCa on post-ESRD mortality. Therefore, we used a large national cohort of 21,826 US veterans with incident ESRD who transitioned to dialysis in all US Department of Veterans Affairs healthcare facilities over 2009-2014 to examine the associations with all-cause and cause-specific post-ESRD mortality of (1) cSCa concentrations averaged over the last six months and (2) its rate of decline during the last 12 months before dialysis initiation. Mean concentrations and median rate of decline of cSCa were 9.3 ± 0.7 mg/dL and -0.15 (interquartile range, -0.39 to 0.07) mg/dL/year, respectively. A total of 9,596 patients died during the follow-up period (mean 1.9 years; total 41,541 patient-years) with an incidence rate of 23.1 per 100 patient-years. There was an independent linear association between higher cSCa with higher mortality (P_trend P_interaction <0.001). Patients with faster decline in cSCa showed lower mortality irrespective of baseline cSCa concentrations. These cSCa-mortality associations were stronger for non-cardiovascular vs. cardiovascular death. In conclusion, lower pre-ESRD cSCa and faster decline in cSCa were consistently and linearly associated with better post-ESRD survival among US veterans, especially for non-cardiovascular death. Further studies are needed to determine if correcting hypocalcemia is beneficial or harmful and which intervention is preferred when indicated among patients with incident ESRD. This article is protected by copyright. All rights reserved