The siblings of patients with seropositive rheumatoid arthritis (RA) had an increased risk for acute coronary syndrome (ACS) compared with the general population, according to study results published in the Annals of the Rheumatic Diseases. The results indicate that there is a shared susceptibility between RA and ACS.

The study included participants with new-onset RA from 1996 to 2016, as well as their full siblings born within 5 years. Participants were matched with up to 5 control participants from the general population who also had at least one full sibling born within 5 years. The researchers used Cox regression to estimate the hazard ratio (HR) of ACS in participants with RA and their siblings compared with the general population.

In total, 8109 participants with incident RA and 11,562 full siblings were identified.

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Compared with the general population, participants with RA had an HR of 1.46 (95% CI, 1.28-1.67) for ACS, while their siblings had an HR of 1.22 (95% CI, 1.09-1.38).

After stratifying the participants by RA serostatus, the researchers found that this effect only remained significant in participants with seropositive RA. These participants had an HR of 1.52 (95% CI, 1.28-1.67) and their siblings had an HR of 1.27 (95% CI, 1.10-1.46). The researchers did not find a significant increase in risk for ACS in siblings of participants with seronegative RA.

These results remained consistent after adjusting for 19 traditional cardiovascular factors.

“From a clinical point of view, our findings serve as a reminder that reducing or removing RA-specific inflammation may in itself not be sufficient to remove the entire excess risk of ACS in RA,” the researchers wrote. “Instead, additional cardio-preventive measures, such as [optimization] of traditional CV risk 9 factors, may be (particularly) important in these patients and among their siblings.”

Reference

Westerlind H, Holmqvist M, Ljung L, et al. Siblings of patients with rheumatoid arthritis are at increased risk of acute coronary syndrome [published online February 20, 2019]. Ann Rheum Dis. doi:10.1136/annrheumdis-2018-214828