Impact of admission calcium-phosphate product on 1-year mortality among hospitalized patients

Document Type : Original Article


1 Department of Medicine, Division of Nephrology, University of Mississippi Medical Center, Jackson, Mississippi; Department of Medicine, Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA

2 Department of Medicine, Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA

3 Department of Internal Medicine, University of Pittsburgh Medical Center Pinnacle, Harrisburg, PA, USA

4 Department of Medicine, Division of Nephrology, University of Mississippi Medical Center, Jackson, Mississippi, USA

5 Department of Internal Medicine, University of Arizona, Tucson, Arizona, USA

6 Division of Nephrology and Hypertension, Mayo Clinic, Jacksonville, FL, USA


Background: Calcium-phosphate product is associated with mortality among patients with end-stage kidney disease on dialysis. However, clinical evidence among hospitalized patients is limited. The objective of this study was to investigate the relationship between admission calcium-phosphate product and 1-year mortality in hospitalized patients. Materials and Methods: All adult patients admitted to a tertiary referral hospital in 2009–2013 were studied. Patients who had both available serum calcium and phosphate measurement within 24 h of hospital admission were included. Admission calcium-phosphate product (calcium × phosphate) was stratified based on its distribution into six groups: <21, 21–<27, 27–<33, 33–<39, 39–<45, and ≥45 mg2/dL2. Multivariate cox proportional hazard analysis was performed to evaluate the association between admission calcium-phosphate product and 1-year mortality, using the calcium-phosphate product of 33–<39 mg2/dL2 as the reference group. Results: A total of 14,772 patients were included in this study. The mean admission calcium-phosphate product was 34.4 ± 11.3 mg2/dL2. Of these patients, 3194 (22%) died within 1 year of hospital admission. In adjusted analysis, admission calcium-phosphate product of ≥45 mg2/dL2 was significantly associated with increased 1-year mortality with hazard ratio of 1.41 (95% 95% confidence interval 1.25–1.67), whereas lower admission calcium-phosphate product was not significantly associated with 1-year mortality. Conclusion: Elevated calcium-phosphate product was significantly associated with increased 1-year mortality in hospitalized patients.


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