Low serum calcium levels associated with sudden cardiac arrest

Patients with lower levels of calcium in the blood are more likely to experience sudden cardiac arrest (SCA), according to a study in Mayo Clinic Proceedings.

Researchers examined 267 SCA cases against 445 control individuals and found each one-unit decrease in calcium levels was associated with a 1.63-fold increase in risk of SCA. All SCA cases had serum calcium measured in the 90 days prior to cardiac arrest, while the control group had calcium measured during routine medical care.

"Our study found that serum calcium levels were lower in individuals who had a sudden cardiac arrest than in a control group,” lead researcher Sumeet S. Chugh, MD, said in a press release. “Patients with serum calcium in the lowest quartile (less than 8.95 mg/dL) had twice the odds of sudden cardiac arrest compared to those in the highest quartile (more than 9.55 mg/dL), even after controlling for multiple patient characteristics including demographics, cardiovascular risk factors and comorbidities, and medication use.”

Hon-Chi Lee, MD, PhD, of the Mayo Clinic’s department of cardiovascular medicine, pointed out in an accompanying editorial it is “the first report to show that low serum calcium levels measured close in time to the index event are independently associated with an increased risk of SCA in the general population."

Lee and the study’s authors suggested further studies to evaluate whether closer monitoring and controlling of calcium levels decreases the rate of SCA in the general population or within at-risk populations. Monitoring calcium levels is relatively easy, they pointed out, and so is increasing calcium intake through dietary changes or supplements.