Accurate recognition of ACS on initial presentation is a key for healthcare providers inside and outside of the hospital setting to the minimization of morbidity and mortality. In this study, older patients (13.4%) visited the hospital significantly more frequently for other symptoms without chest pain, compared with younger patients (7.8%). This is comparable with previous observational studies in which as much as 16.6% of acute myocardial infarction (AMI) patients (8
) and 8.4% of the AMI patients enrolled in the GRACE study experienced no chest symptoms (1
). This finding is in support of the facts that an old age is a factor affecting atypical presentation (2
) and typical symptoms are positive predictors of ACS in younger patients (4
Identifying the symptoms of ACS is important for successful management and especially useful as a guide to their timely treatment of those with atypical symptom presentations. We found that the patients with atypical presentations had a considerable delay in seeking care and had a worse clinical outcome such as longer hospital stay. The dominant presenting symptoms in patients with atypical presentations in this study were abdominal pain/discomforts (38.8%) and dyspnea (36.6%). The GRACE study involving 95 hospitals in 14 countries (1999-2002) reported that 23.8% of the patients presented to the hospital without chest pain were not initially recognized as having an ACS and dominant symptoms were dyspnea (49.3%) and diaphoresis (26.2%) (1
). They were less likely to receive effective cardiac medications, and experienced greater hospital morbidity and mortality than did patients with typical symptoms. After adjustments for confounding variables, an increase in hospital mortality rates was noted in patients with dominant symptoms of syncope, nausea and vomiting, and dyspnea (1
This study for the whole patient group demonstrated that female gender and the histories of diabetes and hypertension were associated with atypical presentation in bivariate analyses, but were not supported as predicting factors by multivariate analysis. This finding is not consistent with previous studies demonstrated that patients with atypical symptoms were more likely to be older, female, hypertensive, diabetic, and to have a history of congestive heart failure (1
). This controversy can be explained by the bivariate analyses of this study that diabetic younger patients were more likely to have atypical presentation compared to non-diabetic younger patients (12.6% vs. 5.9%, P
=0.005), but no association was found in older patients (13.6% vs. 13.4%, P
=0.950). Therefore, diabetes should be carefully interpreted in view of confounding variables such as age distribution or clinical characteristics and the adjustment for them using a multivariate analysis may be required for whole patient group in future study.
Our findings show that dyspnea, indigestion, and nausea/vomiting were more likely to be accompanied by older patients, which is similar to the previous study results (8
). In contrast, older adults with AMI are less likely to complain of chest pain and arm or shoulder pains, which was also consistent with previous studies (8
). This finding supported a previous study that typical chest pain was significantly associated with ACS in younger patients (12
). The dyspnea was represented as a major component of dominant complaints in AMI patients without chest pain (1
). The AMI patients without chest pain were more likely to complain of pulmonary edema (Killip class II and III), require drug treatment for heart failure, and have a prior history of congestive heart failure than patients with chest pain (2
This study found diabetes, which was not a predictor in the whole patient group, to be an independent predicting factor in younger patients presented to the hospital with atypical symptoms when gender and ACS type were controlled for. This finding, which was consistent with previous studies that patients with atypical symptoms were more likely to have diabetes compared with patients having typical symptoms (1
), and identified diabetes as an independent predictor of atypical presentation in women with AMI (13
). About 29% of those sampled for this study had suffered from diabetes, and this was slightly higher than the 25% of the AMI patients with a history of diabetes in the GRACE study (14
). Previous studies reported the impacts of diabetes on the prognosis after ACS such as poor clinical outcomes including heart and renal failure, cardiogenic shock, and death (14
). It is proposed that physicians and primary health care nurses should educate on the management of diabetes and their possible signs and symptoms of ACS for middle-aged diabetic persons at risk for cardiovascular diseases.
However, younger patients with hypercholesterolemia had 50% less chances of having atypical symptoms compared with those with normal serum cholesterol levels. This finding is associated with the fact that the 74% (n=231) of the patients with hyperlipidemia were younger than 70 yr of age in this study. The finding that hyperlipidemic persons were less likely to have atypical symptoms was consistent with the result of GRACE study (1
This study showed that female gender and smoking had slight meaningful negative relationships, which had 14% and 40% respectively less chances of having atypical symptoms in a younger group. Many previous studies supported that women were more likely to have atypical symptoms but those studies were conducted for all age group (1
). Women, in this study, were distributed more than double in older group ≥70 yr compared to younger group (23.0% vs. 51.1%). This supports aging is a more powerful factor on the atypical presentations and female gender should be interpreted with caution for their age distribution.
A significant predicting factor that helps in identifying atypical symptoms in older patients was co-morbidities that they had. This finding was consistent with a previous observational study that the presentation of an atypical symptom was significantly related with a prior history of heart failure or stroke (2
). A qualitative study also supported that women with a concomitant illness thought their symptoms were normal considering their current state of health at the time of their cardiac event (22
). This suggests that the recognition of symptoms on the part of older adults could be masked by concurrent illnesses and that health professionals need to be more alert on the possibility of cardiac related symptoms. This study found about 20% of the older patients sampled had comorbid diseases such as stroke, COPD/asthma, or congestive heart failure. The presence of chronic and persistent diseases was significantly higher in older patients compared with younger patients, who were not affected by atypical symptoms. This greater prevalence of co-morbid chronic diseases might be associated with the fact that having diabetes was not associated with the atypical symptoms among older patients. The 64% of the older patients had hypertension or diabetes (or both), and these risk factors were adjusted for the analysis.
Health care providers should have more concern about diabetic younger adults, and about older adults with chronic concomitant diseases such as stroke and COPD when evaluating patients with no chest pains. Nurse researchers recommended the education targeting individuals at the risk of ACS as well as their families is more efficient method than mass public education campaigns to reduce pre-hospital delays (23
). Therefore, such educational efforts should focus on enhancing awareness of any ACS signs and symptoms in this highrisk group. In addition, it is to be emphasized that the management of social, cognitive, and behavioral manifestations that accompany these symptoms and contribute to the delay.
Further research needs to be undertaken qualitatively for ACS patients with atypical symptoms who delayed presentation to the hospital to have a better understanding the pattern of symptoms and their cognitive responses to their symptoms. In Korea, diabetes and hyperlipidemia significantly predict atypical symptoms in the younger patients with acute coronary syndrome. In the older patients, the co-morbid conditions such as stroke or chronic obstructive pulmonary disease are positive predictors of atypical symptoms. Health care providers need to have an increased awareness of possible presence of ACS in younger persons with diabetes and older persons with chronic concomitant diseases when evaluating patients with no chest pain.