A cluster and inferential analysis of myocardial infarction symptom presentation by age

Background: Pre-hospital delay time in myocardial infarction is usually longer in older than in younger patients, with symptom presentation known to be a contributing factor. Aim: The aim of this article is to examine symptom presentation differences, by age, in patients with myocardial infarction. Methods: This is a cross-sectional study using secondary analysis of a multi-site randomised controlled trial on pre-hospital delay time. Data were analysed using logistic regression and factor analysis. Results: Post-myocardial infarction patients were recruited prior to discharge ( n=1211), 54% were ≥65 years and 80% male. The average number of symptoms was three, with the ≥65 years age group reporting significantly less symptoms. Logistic regression controlling for gender, diabetes and diagnosis with 11 symptoms (χ2=52.09, p<0.001) was significant. Those ≥65 years had less chest symptoms, sweating, stomach upset and left arm pain, in addition to longer pre-hospital delay time. This group also had less symptom clustering and fewer symptoms within atypical clusters. Non-chest clusters occurred in 22% and 18% of the older and younger group respectively. Of note, two clusters ‘atypical’ (upset stomach/sweating) and ‘typical arm’ (right and left arm pain symptoms), accounted for 14% and 5% of myocardial infarction presentations in the ≥65 years group, within which 25% and 24% had no chest symptoms. Conclusions: The results of this study indicate that myocardial infarction symptom presentation in older patients is likely to be less recognisable and more complex. Increased awareness of the presentation profile of older patients could expedite their triage, diagnosis and, consequently, their prognosis.