January 1, 2000Journal of the American College of Cardiology207 citationsOpen Access
Prevalence, predisposing factors, and prognosis of clinically unrecognized myocardial infarction in the elderly
Key Result
In elderly individuals, unrecognized myocardial infarction accounted for 22.3% of prior MIs and was associated with similar 6-year mortality compared to recognized myocardial infarction.
Study Design
Type
Cohort (n=5,888)
Structured PICO
Does unrecognized myocardial infarction have a different 6-year mortality compared to recognized myocardial infarction in elderly patients?
P
Population
5,888 individuals aged ≥65 years, including 901 with a past MI, followed for 6 years to compare outcomes of unrecognized versus recognized myocardial infarction.
E
Exposure
Unrecognized myocardial infarction (UMI) detected by electrocardiographic evidence of a prior Q-wave MI without a history of the diagnosis
C
Comparator
Recognized myocardial infarction (RMI)
O
Outcome
6-year mortalityhard clinical
Unrecognized myocardial infarction accounts for over 20% of MIs in the elderly and carries a similar 6-year mortality risk as recognized MI.
Limitations
- Associations with angina and CHF may represent diagnosis bias.
Abstract
OBJECTIVES: This study was designed to determine the prevalence of unrecognized myocardial infarction (UMI), as well as risk factors, and to compare prognosis after detection of previously UMI to that after recognized myocardial infarction (RMI). BACKGROUND: Past studies revealed that a significant proportion of MIs escape recognition, and that prognosis after such events is poor, but the epidemiology of UMI has not been reassessed in the contemporary era. METHODS: The Cardiovascular Health Study (CHS) database, composed of individuals > or =65, was queried for participants who, at entry, demonstrated electrocardiographic evidence of a prior Q-wave MI, but who lacked a history of this diagnosis. The features and outcomes of this group were compared to those of individuals with prevalent RMI. RESULTS: Of 5,888 participants, 901 evidenced a past MI, and 201 (22.3%) were previously unrecognized. The independent predictors of UMI were the absence of angina and the absence of congestive heart failure (CHF). Six-year mortality did not significantly differ between the two groups. CONCLUSIONS: 1) In the elderly, UMI continues to represent a significant proportion of all MIs; 2) associations with angina and CHF may reflect complex neurological issues, but they also may represent diagnosis bias; 3) these individuals can otherwise not be distinguished from those with recognized infarctions; and 4) mortality rates after UMI and RMI are similar. Future studies should address screening for UMI, risk stratification after detection of previously UMI, and the role of standard post-MI therapies.
Cite This Study
Sheifer et al. (2000) conducted a cohort in Myocardial infarction (n=5,888). Unrecognized myocardial infarction vs. Recognized myocardial infarction was evaluated on 6-year mortality. In elderly individuals, unrecognized myocardial infarction accounted for 22.3% of prior MIs and was associated with similar 6-year mortality compared to recognized myocardial infarction.