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).

Long-term risk of death and MACE in unrecognized MI detected by CMR is as high as recognized MI. Non-fatal MI and heart failure risk is also elevated. https://t.co/gx9amdomrb pic.twitter.com/tl8aCYd5J3

— JAMA Cardiology (@JAMACardio) October 10, 2018

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.” 

Patients with unrecognized #MI had similar #mortality to those with no MI in short term, but by 10 years, unrecognized MI had similar mortality to recognized MI. Interesting finding, but more studies needed to determine need for wider screening https://t.co/Ev3jyzUg1C

— Ron Waksman (@ron_waksman) October 12, 2018

all-cause mortality of unrecognized MI was higher than no MI, but within 10 years from baseline evaluation was equivalent with recognized MI. Unrecognized MI was also associated with an elevated risk of nonfatal MI and heart failure https://t.co/xKucoCEALX

— @investigando (@rocatanho) October 14, 2018

Unrecognized Myocardial Infarction and Long-term Outcomes https://t.co/scCLEAS3I0 The divide between primary and secondary prevention is never absolute. More research needed on ascertainment and on defining of risk

— Garry Jennings (@garryjennings) October 13, 2018

Unrecognised MI identified on 'screening' Cardiac MRI has equal prognosis to recognised (and optimally treated MI)… and worse prognosis than no MI…I ll be controversial… should everyone over the age of 67 have a CMR if option available? @JAMACardio https://t.co/FqLgtL0bIY pic.twitter.com/LxYpqOcyrP

— Vass Vassiliou (@vass_vassiliou) October 13, 2018

Source: JAMA Cardiology