Asthma has been associated with a higher incidence of myocardial infarction (MI), higher prevalence of MI risk factors and higher burden of cardiovascular diseases. However, detailed associations between the presentation and initial management at the time of MI and post-MI outcomes in people with asthma compared to the general population have not been studied. A total of 300,161 people were identified with a first MI over the period 2003-2013 in the Myocardial Ischaemia National Audit Project database, of whom 8922 (3%) had asthma. Logistic regression was used to compare presentation, in-hospital care, in-hospital and 180-day post-discharge all-cause mortality in people with and without asthma adjusting for demographics and comorbidities, diagnosis on arrival and secondary prevention. People with asthma were more likely to have a delay in their MI diagnosis following an STEMI (ST-elevation myocardial infarction; odds ratio (OR) 1.38, confidence interval CI 1.06-1.79) but not an nSTEMI (non-ST-elevation myocardial infarction; OR 1.04, CI 0.92-1.17) compared to people without asthma and a delay in reperfusion (OR 1.19, CI 1.09-1.30) following an STEMI. They were much less likely to be discharged on a beta blocker following an STEMI or nSTEMI (OR 0.24, CI 0.21-0.28 and OR 0.27, CI 0.24-0.30, respectively). There was no difference in in-hospital or 180-day mortality (OR 0.98, CI 0.59-1.62 and OR 0.99, CI 0.72-1.36) following an STEMI or nSTEMI (OR 0.89, CI 0.47-1.68 and OR 1.05, CI 0.85-1.28). Although people with asthma were more likely to have a delay in diagnosis following an STEMI but not an nSTEMI compared to the general population, were more likely to have a delay in reperfusion therapy and were much less likely to receive beta blockers following an STEMI or nSTEMI, there was no difference in the prescriptions of other secondary prevention medications. None of the differences in presentation or management were associated with an increase in all-cause in-hospital or 180-day mortality in people with asthma compared to the general population.
Keywords: Asthma; cardiovascular disease; epidemiology; mortality; myocardial infarction; quality of care.