Correlation of Serum Calcium with Cardiovascular Outcome in Patients with Acute Coronary Syndrome

Background: There have been no studies investigating the relationship between serum calcium level at admission and long-term cardiovascular outcome in patients with the acute coronary syndrome (ACS). Objectives: This study aimed to explore the correlation of admission serum calcium with cardiovascular outcome in ACS patients.Methods: This longitudinal study included 105 ACS or suspected ACS patients who were referred to the Coronary Care Unit between June 1st, 2015, and August 31st, 2016. Serum calcium was measured upon admission, and the patients were followed up till November 30th, 2016. Cardiovascular death or cardiovascular re-hospitalization was the study's end.Results: According to the median of serum calcium, the patients were divided into two groups of lower (n=47) and higher serum calcium (n=58). Kaplan-Meier analysis found that patients with lower serum calcium had an obviously reduced cardiovascular event-free survival (log-rank χ2=5.594, P=0.018), compared to those with higher serum calcium. Furthermore, lower serum calcium level (HR=0.265, 95% CI=0.072-0.981, P=0.047) independently correlated with poor cardiovascular outcome in ACS or suspected ACS patients after adjustment for potential confounders in the multivariable Cox model.Conclusion: Lower serum calcium upon admission independently correlated with poor long-term cardiovascular outcomes in patients with severe coronary artery disease.