ICELAND-MI: Risks from Unrecognized MI Increase Over Time

Mortality from clinically unrecognized myocardial infarction (UMI) wasn’t different from those with no MI, but that changed over time, new study results suggest.  

Researchers for the cohort study included 935 participants in the analysis, who were characterized by cardiac magnetic resonance (cardiac MR). Participants were followed out for up to 13.3 years; Kaplan-Meier time-to-event analyses and Cox regression assessed the link between unrecognized at baseline and death/future cardiovascular events. The outcome of interest was all-cause mortality, and secondary outcomes of composite major adverse cardiac events (death, nonfatal MI, and heart failure).

According to the results, unrecognized myocardial infarction and no MI rates were similar at 3 years, as well as lower than rates of recognized MI. Then, UMI rates increased after 5 years until they were higher than rates of those with no MI (they were still lower than that of patients with recognized MI). By the 10-year mark, UMI and recognized MI rates were not statistically different, and both were significantly higher than those with no MI. After adjustment, UMI was associated with an increased risk for death, major adverse cardiac events, and heart failure compared to those with no MI, and did not differ statistically in terms of death and major adverse events from clinically recognized MI. 

“In this study, all-cause mortality of UMI was higher than no MI, but within 10 years from baseline evaluation was equivalent with RMI,” the researchers concluded. “Unrecognized MI was also associated with an elevated risk of nonfatal MI and heart failure. Whether secondary prevention can alter the prognosis of UMI will require prospective testing.” 

Source: JAMA Cardiology