Myocardial Infarction Symptom Presentation and Hospital Mortality

The hallmark symptom of myocardial infarction (MI) is chest pain/discomfort; however, analyses of data from the National Registry of Myocardial Infarction (NRMI) have shown that some patients do not present with chest pain/discomfort. Those patients tend to present later, receive less aggressive treatment, and have nearly twice the short-term mortality risk compared with those who present with more typical symptoms, including chest pain/discomfort. Furthermore, younger women may be at greater risk of mortality than men, and the lack of chest pain/discomfort on presentation may be a contributing factor to that increase in risk, according to researchers. To determine whether lack of chest pain is, in fact, associated with the higher mortality among younger women with MI, the researchers conducted an observational study utilizing data from the NRMI. The analysis was designed to examine the relationship among patients hospitalized with MI between sex and symptom presentation (primary objective) and sex, symptom presentation, and hospital mortality (secondary objective) after accounting for age. The main outcome measures examined by the researchers were predictors of MI presentation without chest pain and the relationship between age, sex, and hospital mortality. NRMI data from 1994-2006 on 1,143, 513 patients (481,581 women and 661,832 men) were analyzed. Results of the analysis were reported in the Journal of the American Medical Association [2012;307(8):813-822]. At hospital presentation, women with MI were significantly older than men (mean age, 73.9 years vs 66.5 years, respectively; P<.001). At baseline, the proportion of patients presenting without chest pain was 42% for women (95% confidence interval [CI], 41.8%-42.1%) compared with 30.7% for men (95% CI, 30.6%-30.8%), P<.001. The overall proportion of patients who presented without chest pain or discomfort was 35.4% (95% CI, 35.4%-35.5%). There was a significant interaction between age and sex such that sex-specific difference in MI presentation without chest discomfort became progressively smaller with advancing age. Within each age stratum, the researchers performed separate models to calculate the age-stratum–specific odds ratios (ORs) for lack of chest pain for women (referent, men): <45 years of age, OR, 1.30 (95% CI, 1.23-1.36); 45 to 54 years, OR, 1.24 (95% CI, 1.23-1.36); 55 to 64 years, OR, 1.24 (95% CI, 1.21-1.27); 65 to 74 years, OR, 1.13 (95% CI, 1.11-1.15); and ≥75 years, OR, 1.03 (95% CI, 1.02-1.04). The statistical significance for trend of the OR by increasing age and for the interaction between sex and age was significant (P<.001). For women, the in-hospital mortality rate was 14.6%, and for men it was 10.3%. For younger women presenting without chest pain, the in-hospital mortality rate was greater than for younger men without chest pain. These differences associated with sex decreased or even reversed with advancing age. The adjusted OR for age <45 years was 1.18 (95% CI, 1.00-1.39); for 45 to 54 years, 1.13 (95% CI, 1.02-1.26); for 55 to 64 years, 1.02 (95% CI, 0.96-1.09); for 65 to 74 years, 0.91 (95% CI, 0.88-0.95); and ≥75 years, 0.81 (95% CI, 0.79-0.83). The 3-way interaction (sex, age, and chest pain) on mortality was significant (P<.001). The researchers commented that the “data suggest that the absence of chest pain may be a more important predictor of death in younger women with MI compared with other similarly aged groups.” In summary, the researchers said that, “in this registry of patients hospitalized with MI, women were more likely than men to present without chest pain and had higher morality than men within the same age group, but sex differences in clinical presentation without chest pain and in mortality were attenuated with increasing age.”