How Autoimmune Disorders Impact Myocardial Infarction Treatment and Long-Term Outcomes

Among patients hospitalized for myocardial infarction (MI), the presence of a rheumatic immune-mediated inflammatory disease (IMID) was associated with reduced use of coronary interventions and significantly increased risks of all-cause mortality and adverse cardiovascular outcomes in the next two years, finds a large Medicare database analysis published in Journal of the American Heart Association (2022;11:e026411).

“Autoimmune disorders are associated with myriad cardiovascular manifestations and an elevated risk of premature coronary artery disease,” says Cleveland Clinic cardiologist Amgad Mentias, MD, MSc, the study’s corresponding author. “Nevertheless, studies of post-MI outcomes in patients with autoimmune disorders have been limited in size and yielded inconsistent results. We conducted our analysis, the largest and most contemporary study of this population to date, to better understand how the presence of autoimmune disorders affects MI treatment and long-term outcomes.”

Assessing autoimmune disease prevalence among MI patients

Using the nationwide Medicare Provider Analysis and Review (MedPAR) database, Dr. Mentias and Cleveland Clinic colleagues identified 1.65 million Medicare beneficiaries hospitalized with an MI diagnosis from 2014 to 2019. They then identified those who had a concomitant rheumatic IMID, who totaled 60,072, or 3.6% of the cohort. The IMIDs consisted of the following:

• Rheumatoid arthritis (n = 46,747)
• Systemic lupus erythematosus (n = 7,362)
• Psoriasis (n = 3,098)
• Systemic sclerosis (n = 1,738)
• Myositis/dermatomyositis (n = 1,127)

Compared with the rest of the cohort, those with a rheumatic IMID were slightly but significantly younger, more likely to be women (66.9% vs. 44.2%) and more likely to present with non-ST-elevation MI (non-STEMI) than with STEMI. Additionally, rates of coronary angiography, percutaneous coronary intervention and coronary artery bypass grafting were all significantly lower in patients with versus without a rheumatic IMID, regardless of MI type (non-STEMI or STEMI).

MI outcomes with and without autoimmune disease

To assess clinical outcomes, the researchers applied a 1:3 propensity-score matching scheme to match cohort patients with a rheumatic IMID (n = 59,820) with cohort patients without a rheumatic IMID (n = 178,547). By design, the arms were identically matched for age, sex, race, and prevalence of non-STEMI versus STEMI, with comorbidities and other variables well balanced between the groups.

Over median follow-up of 24 months (interquartile range, 9-45 months), the study’s primary outcome of all-cause mortality was significantly higher in MI patients with versus without a rheumatic IMID (hazard ratio [HR] = 1.15 [1.14-1.17]; P < 0.001). The presence of a rheumatic IMID conferred significant increases in a number of secondary outcomes as well, including:

• Heart failure (12% relative increase; P < 0.001)
• Recurrent MI (8% relative increase; P < 0.001)
• Need for coronary reintervention (6% relative increase; P = 0.04)

These elevated risks with rheumatic IMIDs remained statistically significant after sensitivity analysis using multivariable Cox regression analysis.

Clinical takeaways for a challenging population

“This study yielded several notable findings,” says Dr. Mentias. “First, underlying rheumatic autoimmune disease was associated with a 15% relative rise in the risk of all-cause mortality by one year after MI and continuing throughout follow-up. Second, it was also associated with poorer outcomes in multiple other cardiovascular endpoints. Finally, MI patients with rheumatic autoimmune disease were predominantly female and were less likely to undergo coronary angiography or revascularization for their MI.”

The latter finding is provocative, the authors note. “It is possible that, despite the propensity matching, the patients with autoimmune disease were clinically more ill or had coronary anatomy that was less suited to revascularization,” says Cleveland Clinic cardiologist and study co-author Khaled Ziada, MD. “Unfortunately, the database did not contain information specific to coronary anatomy. However, autoimmune disease per se does not preclude revascularization when that is considered to be feasible and safe.”

“This study’s findings reinforce our recommendation that patients with concurrent autoimmune disease and cardiovascular disease be managed by a cardio-rheumatologist in conjunction with a rheumatologist,” adds co-author Heba Wassif, MD, MPH, Director of Cleveland Clinic’s Center for Cardio-Rheumatology and Immunology. “Such providers are well equipped to offer what these patients often need when presenting with MI — namely, coronary intervention, aggressive risk factor optimization and medical therapy intensification to attenuate their increased cardiovascular risk.”