Myocardial infarction (MI) is the most common, acute manifestation of coronary artery disease (CAD) and about 790,000 Americans have an MI each year. Recent research has identified novel risk factors for CAD, including characteristics associated with metabolic syndrome, such as obesity, a lack of physical activity, and stress. Other data show that gout is associated with three-fold higher prevalence of metabolic syndrome, a condition that has been linked to a higher prevalence of MI risk factors like hyperlipidemia, hypertension, and diabetes. Gout has also been associated with a 1.6-fold higher risk of incident CAD, even after adjusting for blood pressure, cholesterol, alcohol use, BMI, and diabetes.
“Despite the well-established link between gout and heart disease, few studies have explored the risks of MI that are associated with gout in older patients,” explains Jasvinder A. Singh, MD. Patients aged 65 and older are at high risk of MI and poorer outcomes from CAD events. Given this substantial public health burden, research is needed to assess potential cardiac risks that are associated with gout. To address this gap, Dr. Singh and colleagues conducted a study to assess whether gout was associated independently with a higher risk of incident MI in the elderly. The analysis also looked at whether this association varied by CAD risk factors, including hypertension, hyperlipidemia, and diabetes.
A Large Data Analysis
The study, published in Arthritis Research and Therapy, examined Medicare claims data on more than 1.7 million eligible people to examine the link between patients with gout at baseline and incident MIs during follow-up. Data were adjusted using three different models based on patient demographics, medical comorbidity using the Charlson–Romano index, and commonly used cardiovascular and gout medications. “Our study showed an association between gout and incident MI in older adults that was independent of traditional CAD risk factors,” says Dr. Singh.
In multivariable-adjusted analyses, gout was significantly associated with a higher risk for incident MI, with an overall hazard ratio (HR) of 2.08 (Table). Interestingly, the MI risk associated with gout was stronger among people who did not have CAD risk factors when compared with those who had such risk factors. In subgroup analyses, HRs of gout with incident MI were higher when hypertension, hyperlipidemia, diabetes, or heart failure were absent when compared with HRs in those with each of these comorbidities. The authors also observed minor differences in the domains of age, gender, and race.
The finding that gout was more strongly associated with incident MI in people without hypertension, hyperlipidemia, or diabetes indicates that gout contributes much less to the risk of incident MI in patients with known CAD/MI risk factors. This may be due to gout being an early clinical manifestation of metabolic syndrome. Another factor may be that the episodic inflammation that is characteristic of gout flares may increase risks for MI, especially in those without other CAD risk factors.
Considering the Implications
Dr. Singh says the increased risk of new MI in people with gout raises an important question regarding the role of chronic inflammation and other hallmarks of gout in the pathogenesis of MI. “It’s possible that inflammatory pathways may be activated in the atherosclerotic plaque, which may then lead to MI,” he says. “People with gout have upregulation of inflammatory pathways, which might explain the increased risk of MI in gout. We’re gaining a better appreciation that chronic inflammation is implicated in both gout and incident MI, but more research is needed to evaluate the mechanisms for this association and determine to what extent this link is due to chronic inflammation or other potential pathways.”