Use of intravenous magnesium sulfate among patients with acute myocardial infarction in China from 2001 to 2015: China PEACE—Retrospective AMI Study

OBJECTIVE: In 2001, Chinese guidelines for the care of acute myocardial infarction (AMI) included a new recommendation against the routine use of magnesium. We studied temporal trends and institutional variation in the use of intravenous magnesium sulfate in nationally representative samples of individuals hospitalised with AMI in China between 2001 and 2015. METHODS: In an observational study (China PEACE—Retrospective Study) of AMI care, we used a two-stage, random sampling strategy to create a nationally representative sample of 28 208 patients with AMI at 162 Chinese hospitals in 2001, 2006, 2011 and 2015. The main outcome is use of intravenous magnesium sulfate over time. RESULTS: We identified 24 418 patients admitted for AMI, without hypokalaemia, in the four study years. Over time, there was a significant initial decrease in intravenous magnesium sulfate use, from 32.1% in 2001 to 17.1% in 2015 (p<0.001 for trend). The decline was greater in the Eastern (from 33.3% to 16.5%) and Western (from 34.8% to 17.2%) regions, as compared with the Central region (from 25.9% to 18.1%), with little difference between rural and urban areas. The proportion of hospitals using intravenous magnesium sulfate did not change over time (from 81.3% to 77.9%). The median ORs, representing hospital-level variation, were 6.03 in 2001, 3.86 in 2006, 4.26 in 2011 and 4.72 in 2015. Intravenous magnesium sulfate use was associated with cardiac arrest at admission and receipt of reperfusion therapy, but no hospital-specific characteristics. CONCLUSIONS: Despite recommendations against its use, intravenous magnesium sulfate is used in about one in six patients with AMI in China. Our findings highlight the need for more efficient mechanisms to stop using ineffective therapies to improve patients’ outcomes and reduce medical waste. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov (NCT01624883)