Asthma May Significantly Increase Odds of Heart Attack

Chicago—Asthma and cardiovascular disease (CVD) share an inflammatory pathophysiology. Asthma affects more than 2.5 million individuals in the United States, with the highest prevalence among ethnic minorities. CVD is the leading cause of death among adults in the United States. Recent asthma symptoms or asthma that requires daily medication may significantly increase the risk of heart attack, according to the findings from 2 studies presented at the AHA meeting.

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In the first study, the presence of chronic asthma and use of controller medications (inhaled corticosteroids, leukotriene inhibitors, and oral corticosteroids) were assessed in the 6-community MESA [Multi-Ethnic Study of Atherosclerosis] trial, which tracked early signs of developing heart disease. MESA involved 6792 participants, of which 156 were asthmatics on controller medications, 511 were asthmatics but not on controller medications, and 6125 were nonasthmatics.

The average age of the study participants was 62.2 years, 47% were male, 28% were white, 28% were black, 22% were Hispanic, and 12% were Chinese-American. The cohort was followed for a mean of 9.1 years for development of CVD (coronary death, myocardial infarction [MI], angina, stroke, and CVD death). Multivariable Cox regression models were used to assess associations of chronic asthma and CVD.

After adjusting for heart disease risk factors, the researchers found that individuals with asthma who required daily medications were 60% more likely to have a cardiovascular event such as heart attack, stroke, or a related condition during a 10-year follow-up compared to individuals without asthma. Asthmatics on controller medications compared with nonasthmatics had significantly higher levels of inflammatory markers including C-reactive protein (1.2 mg/L vs 0.6 mg/L, respectively) and fibrinogen (379 mg/dL vs 345 mg/dL, respectively).

“Physicians should do all they can to control every other modifiable cardiovascular risk factor in patients with asthma,” said the study’s author, Matthew C. Tattersall, DO, MS, assistant professor of medicine, division of cardiology, University of Wisconsin-Madison School of Medicine and Public Health, in a press statement.

The nature of the relationship between asthma and the risk of MI is poorly understood, resulting in confusion and concern among patients, clinicians, and the public health community. In the second study, the researchers sought to determine whether asthma or other atopic conditions are associated with risk of MI.

The population-based, retrospective, case-control study identified 693 Olmsted County, Minnesota, residents who developed MI between November 1, 2002, and May 31, 2006. MI was defined using standard criteria, including chest pain, electrocardiographic data using Minnesota coding, and cardiac enzyme levels (cutoff value of cardiac troponin T used at Mayo Clinic, ≥0.03 ng/mL). Asthma status was ascertained using predetermined criteria for asthma. Active asthma was defined as the presence of asthma symptoms, use of asthma medications, and unscheduled medical visits for asthma within 1 year prior to MI index date.

Of the 693 MI cases, 543 were eligible for study inclusion, of which 44% were female, 95% were white, and the mean age was 67.5 years. Of the 543 MI cases, 81 individuals (15%) had a history of asthma prior to the index date of MI; whereas, 52 of the 543 matched controls (10%) had such a history, controlling for all significant comorbid conditions, including chronic obstructive pulmonary disease (COPD). After controlling for traditional risk factors for MI (eg, obesity, smoking, and high blood pressure), pertinent comorbid conditions, including COPD, and asthma medications, the researchers found that patients diagnosed with asthma had about a 70% higher risk of MI than those without asthma. For patients with active asthma, the odds of MI were 2-fold higher than asthma patients with no recent symptoms.

“Chest discomfort or pain can be confused as a symptom of asthma, but because asthma increases the risk of heart attack and treatments for each are quite different, patients need to take chest pain and other symptoms of heart attack seriously and seek prompt treatment,” said the study’s senior author, Young J. Juhn, MD, MPH, professor of pediatrics and adolescent medicine, Mayo Clinic, Rochester, Minnesota.—Eileen Koutnik-Fotopoulos