With little research and no clear guidelines, physicians have to rely on expert opinions and their own experience when treating patients with both rheumatic and cardiovascular conditions. It’s a significant patient population, treatment is more dynamic and the risk stratification is a moving target, according to rheumatologist and clinical investigator Katherine Liao, MD, of Brigham and Women’s Hospital in Boston.
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“The relationship between cholesterol, cardiovascular risk and inflammation is different in patients with rheumatic disease. In the general population, higher cholesterol means higher cardiovascular risk. That is not necessarily the case with [our] patients,” says Dr. Liao. “With rheumatic diseases, such as RA [rheumatoid arthritis], we know that treating to general population guidelines is suboptimal. However, we do not yet have data that definitively tell us, ‘yes, if you reduce inflammation, you will reduce cardiovascular risk by X%.’”
Dr. Liao says the general population guidelines typically underestimate cardiovascular risk in RA patients by 1.5 to two times. However, the math isn’t that simple.
“The problem is always confounded by the patients’ level of disease activity or inflammation. That can modify what the patients’ risk is,” she notes. “We want to be able to better estimate risk, but we don’t really have a way to do that yet. That is what a lot of studies are looking at.”
Dr. Liao points out that patients with rheumatic conditions routinely incur inflammation changes, and as a result, changes to lipid levels. Although no validated formula exists, understanding the variance is key, as is knowing when your patient is an outlier due to “flares, length of time the patient has had a rheumatic disease or how much steroid treatment the patient has had.”
When evaluating patients with a C-reactive protein (CRP) test, clinicians should be wary of the results for patients with active rheumatic conditions. In the general population, a CRP result of 3 mg/L is considered elevated and a patient with that result is considered at high risk of heart disease.
“But in RA, you are dealing with a completely different scale,” she says. “The mean CRP in a well-treated RA cohort is about 9 mg/L. If patients are flaring, the CRP easily could be in the 20s or 50s, and it is not unusual to see a level of 100 mg/L. It is a completely different scale of inflammation, and again, we don’t have data on how we should be integrating this information about how we assess [cardiovascular] risk.