Low serum calcium levels on admission independently predict mortality in patients with acute myocardial infarction
Abstract Background Serum calcium levels were reported to be associated with risk of cardiovascular diseases. The aim of this study was to analyze the association between serum calcium levels and all-cause mortality in patients with acute myocardial infarction (AMI). Methods A total of consecutive 3886 AMI patients with serum calcium data available were included in this analysis. The baseline characteristics, including clinical and laboratory parameters were collected. Patients were classified into 4 equally-sized groups based on serum calcium values (≤2.15, 2.16–2.23, 2.24–2.31, ≥2.32 mmol/L). Serum calcium tests were finished within 12 hours after admission. Patients were followed up for a median of 2.0 years (interquartile range 0.6–4.0). The primary endpoint was all-cause mortality. Results Compared to upper quartiles of serum calcium groups, subjects in the lowest quartile group (≤2.15 mmol/L) were older, lower body mass index (BMI), had lower levels of LDL-C and albumin, but higher level of NTproBNP. During a median follow-up period of 2.0 years, all-cause death occurred significantly more in the lowest quartile group (19.8%, 11.9%, 8.0% and 9.2% among the 4 groups from lowest to highest quartile, p<0.001 for trend). After adjusting for potentially confounding variables, the Cox analysis revealed that low serum calcium levels independently predict subsequent all-cause mortality (OR=0.36, 95% CI: 0.18–0.73), and identified that older age, lower BMI, smoking, and higher levels of creatinine were also independently associated with increased risk of mortality. Conclusion Low serum calcium levels on admission independently predict mortality in patients with AMI. Further studies are required to determine whether calcium supplementation could improve outcomes in AMI patients with hypocalcemia. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Beijing Natural Science Foundation (no. 7194253);Scientific Research Common Program of Beijing Municipal Commission of Education (KM201910025017)