Current evidence suggests that gout is independently associated with a higher risk of myocardial infarction (MI), but data in older adults at the highest risk of MI are lacking. Our objective was to examine whether gout is associated with a higher risk of incident MI in older adults

Myocardial infarction (MI) is the most common, acute manifestation of coronary artery disease (CAD), which is the most common cardiovascular disease. Although MI incidence decreased slightly from 1999 to 2008, 790,000 Americans have MI each year.

MI is associated with high mortality rate and significant health care costs. Thus, MI is a significant public health problem with a huge burden on society and the healthcare system.

Traditional risk factors for CAD are well known and include hypertension, hyperlipidemia, diabetes, smoking, family history, age, and postmenopausal status. Lately, novel risk factors for CAD have been identified, such as obesity, lack of physical activity, and stress.

Recognition of novel risk factors for MI can improve our understanding of the disease as well as offer new therapeutic targets, in addition to the currently effective strategies for primary and secondary prevention and treatment of MI.

Results

We assessed the 2006-2012 Medicare 5% claims data for the association of gout at baseline with the occurrence of a new (incident) MI during follow-up, adjusting for patient demographics, medical comorbidity (Charlson-Romano index), and commonly used cardiovascular and gout medications, in a Cox proportional hazards model. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated.

In a cohort of 1,733,613 eligible people, 14,279 developed incident MI: 13,029 MIs in people without gout and 1250 MIs in those with gout, with crude incidence rates of 1.3 vs 4.1 per 1000 person-years, respectively. In multivariable-adjusted analyses, gout was significantly associated with a higher hazard of incident MI, with HR of 2.08 (95% CI 1.95, 2.21).

The risk was minimally attenuated in sensitivity analyses that replaced the continuous Charlson-Romano index score with a categorical score or individual comorbidities, or expanding to a more sensitive diagnostic algorithm for incident MI, or additionally adjusting for obesity.

Gout was independently associated with a higher risk of MI in the elderly, aged 65 years or older. The role of inflammatory and other pathways need to be explored as underlying mechanisms for this association.