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Antiphospholipid antibodies independent risk factor for MI

Antiphospholipid antibodies and immunoglobin G positivity were strongly associated with first-time myocardial infarction independent of traditional risk factors, according to research published in Annals of Internal Medicine.

“Long-term anticoagulation prevents new thrombotic events in most patients with antiphospholipid syndrome,” Giorgia Grosso, MD, research assistant at Karolinska Institutet, Stockholm, Sweden, and colleagues wrote. “Information on prothrombotic antiphospholipid antibodies in patients with MI is conflicting, due to limited sample sizes, selected populations, and nonstandardized methods in previous studies.”

Grosso and colleagues conducted a large, multicenter, case–control study to compare the frequency of anti–beta2-glycoprotein I and anticardiolipin of IgG/IgA/IgM isotypes and antinuclear antibodies among patients with first-time MI vs. matched control participants. The researchers included 805 Swedish patients aged 75 years or younger who were hospitalized for a first MI between 2010 and 2014. These patients were matched to controls (n = 805) based on age, sex and region.

Participants were enrolled at the time of hospitalization and were scheduled for an inclusion visit 6 to 8 weeks later to obtain blood samples. They were required to fast and abstain from smoking during the 12 hours before the inclusion visit.

The researchers found that patients with MI were more likely to have that IgG anti–beta2-glycoprotein I and/or IgG anticardiolipin than control patients (11.1% vs. 1.3%). Patients with MI were also likely to have high IgG levels. However, there was no difference IgA/IgM isotypes between groups.

Adjusted analysis indicated that MI was associated with antiphospholipid antibodies IgG positivity (OR = 7.8; 95% CI, 4-15.3) and current smoking (OR = 2.6; 95% CI, 1.9-3.5), but not diabetes, hypertension or BMI.

Women (26.1% vs. 17.9%; P = .062) and current smokers (33.7% vs. 25.1%; P = .085) were nonsignificantly more likely to have antiphospholipid antibodies IgG positivity.

“A strong and independent association between antiphospholipid antibodies IgG positivity and first-time MI may represent an important, but until now neglected, risk factor for MI in the general population,” Grosso and colleagues concluded. “If confirmed in long-term cohort studies, these findings may lead to improved management, treatment, and outcomes for many patients who have had or are at high risk for MI.” – by Alaina Tedesco

Disclosures: Grosso reports no relevant financial disclosures. Please see study for all other authors’ relevant financial disclosures.