“Lipid Paradox” Creates Comparable Risk for RA Patients

Researchers have found that the relationship between low-density lipoprotein (LDL) cholesterol levels and cardiovascular (CV) risk in patients with rheumatoid arthritis (RA) doesn’t differ greatly from that found in patients without RA in the same age group and of the same sex.

A team of investigators from Brigham and Women’s Hospital—who note that RA patients did have a 1.7-fold greater risk of cardiovascular disease (CVD) compared to matched non-RA subjects—sought to study the U-shaped relationship between LDL cholesterol levels and CV risk, known as the lipid paradox. The authors studied 16,085 patients with RA, and 48,499 controls without RA. Adults in the United Healthcare database who had LDL and high-density cholesterol (HDL) measurements were eligible for the study.  
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The rates of risk of major adverse CV events (MACE) were 14.2 per 1,000 person-years of follow-up in the RA cohort, compared to 7.1 per 1,000 person-years of follow-up in the control group. A similar U-shaped relationship between LDL cholesterol levels and the incidence of MACE was seen in both the RA cohort as well as the control group, in which subjects at the greatest risk for MACE demonstrated both the lowest and highest LDL cholesterol levels. The relationship between LDL cholesterol levels and MACE risk in the non-RA cohort was “nonlinear,” according to the authors, who report finding no significant difference in the relationship between LDL cholesterol levels and the incidence of MACE between the RA and non-RA groups.

The risk of MACE was highest in participants with low HDL cholesterol levels compared to those with higher levels of HDL cholesterol. The researchers observed this finding both groups, and found the relationship between HDL cholesterol levels and the risk of MACE was nonlinear in the controls, and similar in RA patients.

When the cohorts were combined for analysis, each progressively higher quintile of HDL cholesterol levels was found to be connected to a lower MACE risk in comparison with the lowest quintile. After adjusting for CV risk factors, those in the highest quintile of HDL cholesterol levels had a 55% lower MACE risk in comparison to the lowest quintile.

At the moment, “the most important step for primary care practitioners [is to] be aware of the elevated CV risk in RA patients, and proactively screen and treat for cardiovascular disease,” says Katherine Liao, MD, MPH, an assistant professor of medicine at Harvard Medical School, and lead author of the study.

Liao notes that more research must be done in order to develop methods for improving the stratification of CV risk in RA patients, which “will allow us to accurately identify high-risk patients and determine if different treatment strategies, e.g., more aggressive lipid lowering or control of inflammation, reduce the risk.”

—Mark McGraw

Reference

Liao K, Liu J, et al. Association Between Lipid Levels and Major Adverse Cardiovascular Events in Rheumatoid Arthritis Compared to Non-Rheumatoid Arthritis Patients. Arthritis Rheumatol. 2015.