Two studies find that active asthma increases risk of cardiovascular events

Presented at the AHA Scientific Sessions 2014 by: Matthew Tattersall en Duk Won Bang (Mayo Clinic, Rochester, MN)
 Both asthma and cardiac disease are associated with increased levels of systemic inflammation. Asthma is a Th2-biased inflammatory condition associated with pro-inflammatory conditions (Th1-biased) like coronary heart disease, although these findings have not been consistent. The relation between asthma and the risk of myocardial infarction is currently poorly understood.
Two studies investigated this relation: the Mayo Clinic conducted a prospective population-based case-control study with patients with myocardial infarction (MI), chest pain and cardiac troponin T >0.03 ng/mL, and matched controls without a history of MI. In the Multi-Ethnic Study of Atherosclerosis (MESA) the link between asthma and progression of subclinical CVD was studied.

Results

• The Mayo Clinic study (Bang et al.) found a univariate association between a history of asthma and the risk of MI  with OR: 1.73 (95%CI: 1.17-2.54), and multivariate analysis yielded OR: 1.36 (95%CI: 0.85-2.17).
• Active astma yielded a univariate OR of 2.90 (95%CI: 1.60-5.26) and multivariate OR: 2.30 (95%CI: 1.12-4.72), while inactive asthma gave a univariate OR of 1.14 (95%CI: 0.69-1.89) and  a multivariate OR: 0.91 (0.49-1.67), as compared with no asthma.
• Treatment of active asthma with inhaled corticosteroids and systemic corticosteroids reduced the risk of MI, and the same was true for short or long-acting beta-agonists, but an increased risk of MI remained.
• The MESA study (Tattersal et al.) found that persistent asthma was associated with an increased risk of CVD events in static models with increasing extent of correction (model 1: HR: 1.72, 95%CI: 1.14-2.59, P=0.010, model 4: HR: 1.59, 95%CI: 1.01-2.50, P=0.04).
• Intermittent asthma did not significantly increase the risk of CVD events.
• Systemic inflammatory markers IL-6, CRP and fibrinogen were significantly higher in people with persistent asthma and D-dimer was signficantly lower than in people without asthma.

Conclusion

Active asthma thus seems to be associated with an increased risk of MI. This association was not impacted by traditional risk factors for MI, pertinent comorbid conditions like COPD and was not influenced of asthma medication. Clinicians and patients have to be aware of this risk because symptoms can be similar.
People with persistent asthma also had a higher risk of CVD events than people without asthma. Despite treatment, people with persistent asthma did have the highest burden of systemic inflammation