Hospital mortality and long-term mortality among hospitalized patients with various admission serum ionized calcium levels

ABSTRACT

Background

We conducted a single-center historical cohort study to evaluate the association between admission serum ionized calcium and mortality in hospitalized patients.

Methods

We included hospitalized patients from January 2009 to December 2013 who had available serum ionized calcium at the time of admission. We assessed the in-hospital and 1-year mortality risk based on admission serum ionized calcium using multivariate logistic and Cox proportional hazard analysis, respectively. To test non-linear association, we categorized serum ionized calcium into six groups; ≤4.39, 4.40–4.59, 4.60–4.79, 4.80–4.99, 5.00–5.19, ≥5.20 mg/dL and selected serum ionized calcium of 4.80–4.99 mg/dL as a reference group.

Results

We studied a total of 33,255 hospitalized patients. The mean admission serum ionized calcium at 4.8 ± 0.4 mg/dL. Hospital and 1-year mortality observed in 1,099 (3%) and 5,239 (15.8%), respectively. We observed a U-shaped association between admission serum ionized calcium and in-hospital and 1-year mortality. Ionized calcium lower threshold for increased in-hospital and 1-year mortality rates was ≤4.59 and ≤4.39 mg/dL, respectively. Ionized calcium upper threshold for increased in-hospital and 1-year mortality rates was ≥5.20 mg/dL.

Conclusion

Both hypocalcemia and hypercalcemia were associated with increased short- and long-term mortality with a U-shape relationship.

KEYWORDS:

• Ionized calcium
• calcium
• mortality
• outcomes
• hospitalization

Authors contributions

All authors had access to the data and a role in writing the manuscript.

Declaration of interest

The contents of the paper and the opinions expressed within are those of the authors, and it was the decision of the authors to submit the manuscript for publication. The authors declare they have no conflict of interest.

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.