Three-year mortality in patients suspected of acute myocardial infarction with and without confirmed diagnosis. The Danish Study Group on Verapamil in Myocardial Infarction.

The 3-year mortality from day 15 after admission was evaluated prospectively in 11,345 consecutive patients with chest pain suspected of myocardial infarction--4,265 patients with confirmed diagnosis (AMI) and 7,080 patients without confirmed diagnosis (non-AMI), respectively. The mortality rates per year in the first 3 years in the patients with AMI were 14.2%, 6.9%, and 7.6%, and in the non-AMI patients were 8.8%, 5.8%, and 5.5%. The standardized mortality ratio (SMR) correcting for age and sex differences was calculated. SMR is the ratio between the observed mortality in the study population and the expected mortality in an age- and sex-matched subgroup of the general background population. SMR in the first year was 6.7 (95% confidence limits: 6.2 to 7.2) in AMI and 4.7 (4.4 to 5.1) in non-AMI patients. In the second and third years of follow-up, SMR was 3.0 (2.6 to 3.4) and 2.9 (2.5 to 3.4) in AMI and 2.8 (2.5 to 3.1) and 2.4 (2.1 to 2.8) in the non-AMI patients. It is concluded that in the first 3 years the mortality of non-AMI patients is approximately three times higher than in the general population and very close to the late mortality of AMI patients, suggesting that the majority of non-AMI patients are suffering from ischemic heart disease also. Non-AMI patients should consequently be evaluated carefully prior to discharge.