Cardiovascular Disease Risk in Patients with Rheumatic Diseases By Marwa Mohiy

The current review focuses on the following (1) the role of dyslipidemia in RA-related CVD risk (2) risk of inflammation-related myocardial disease and eventual HF (3) the emergence of RA disease activity as a key focus for CVD risk prediction and CVD risk reduction in RA.

Increased cardiovascular disease (CVD) risk has been reported for rheumatoid arthritis (RA) and other inflammatory autoimmune rheumatic diseases, which have a lifetime risk of adult onset of 1 in 12 for women and 1 in 20 for men. This review focuses on the most common, RA, which occurs 2 to 3 times more often in women than men.

The risk for CVD and total mortality is greater than 1 The risk for CVD and total mortality is greater than 1.5 times higher in RA patients and 10-year CVD risk scores underestimate risk. CVD is more likely to be fatal as unrecognized myocardial infarctions (MI), coronary heart disease (CHD), venous thrombosis, sudden death, and heart failure (HF) specifically with preserved ejection fraction (HFPEF are increased. More aggressive primary and secondary prevention of CVD is needed in RA patients, many of whom are postmenopausal women.

The greater risk of CVD exists at most levels of traditional CVD risk factors, even among individuals with no smoking, diabetes, hypertension, or history of hypercholesterolemia, as shown in the Women’s Health Initiative (WHI) RA Study (Table 1). CVD risk in RA is strongly related to traditional CVD risk factors, for example, cigarette smoking, hypertension, diabetes, and hyperlipidemia. The risk factor profile in RA (Box 2) includes higher prevalence of smoking, hypertension, diabetes, and obesity, although some RA patients have low body mass index (BMI).

. One study showed increased myocardial ischemia levels in RA patients without evidence of obstructive coronary artery disease. Inflammatory markers that are increased in RA (eg, erythrocyte sedimentation rate [ESR], CRP, white blood cell count, and cytokines, including IL-6 and TNF-a) have stronger associations with myocardial microvascular endothelial dysfunction, remodeling, interstitial fibrosis, and diastolic dysfunction, leading to HF and fatal CVD.

? The role of dyslipidemia in RA has been questioned due to a “ lipid paradox.” RA patients have lower levels of total cholesterol (TC) and low-density lipoprotein (LDL) cholesterol (LDL-C) than adults without RA Increased CVD risk is associated with low levels of TC and LDL-C. Total and LDL-C levels decrease before RA diagnosis, often increase in response to anti-inflammatory medications, and decrease in response to flares of RA disease activity.

The paradoxically low total and LDL-C levels contribute to underestimation of CVD risk by CVD risk scores (eg, Framingham Risk Score, Reynolds Risk Score, and SCORE [Systematic Coronary Risk Evaluation]), which have been shown to incorrectly classify as “low risk” approximately 60% of RA patients with coronary artery calcification and approximately one-third of those who subsequently had CVD events.

WHAT EXPLAINS THE EXCESS CARDIOVASCULAR DISEASE RISK IN RHEUMATOID ARTHRITIS?

Active RA is characterized by systemic inflammation that is credited with much of the excess risk of CVD and mortality in RA. The contribution of inflammation to atherosclerosis, endothelial dysfunction, plaque vulnerability, and atherothrombotic events has been previously reviewed. Reduction of CVD risk has been reported using several anti-inflammatory disease-modifying antirheumatic drugs (DMARDs), including hydroxychloroquine and methotrexate, and possibly for biological medications such as tumor necrosis factor (TNF-a) inhibitors

Randomized clinical trials are underway, testing methotrexate and an anti-interleukin (IL)-1b antibody (canakinumab) for secondary prevention of CVD events among adults without RA. RA-associated inflammation also contributes to the development of dysfunctional high-density lipoprotein (HDL) as recently reviewed.

ROLE OF DYSLIPIDEMIA IN CARDIOVASCULAR DISEASE RISK IN RHEUMATOID ARTHRITIS

The “lipid paradox” in RA describes the seemingly paradoxic association of low levels of total and LDL cholesterol with increased CVD risk. However, recent large studies show a J-shaped association of LDL-C with CVD in RA, that is similar to non-RA controls. Indeed, the lipid paradox of high CVD risk with normal or low LDL-C is well known in adults with the metabolic syndrome, diabetes, or obesity. These conditions are characterized by increased levels of inflammation, triglycerides, and small, dense, cholesterol-depleted LDL particles (LDL-P) that result in increased levels of LDL-P levels despite decreased levels of LDL-cholesterol (LDL-C) levels.

LDL-P can be measured directly or estimated by ApoB concentration, because there is one apoB per LDL and very LDL particle, and w 90% are LDL-P. When discordance exists between concentrations of atherogenic lipoproteins (eg, apoB, LDL-P) and their cholesterol content (LDL-C or non-HDL-C), CVD risk is better estimated using particle concentrations rather than cholesterol level, as demonstrated in the Multi-Ethnic Study of Atherosclerosis and other studies. The effect of HDL on CVD risk is much more complicated.

Measurements of apo B, LDL-P, apoA1, and HDL-P may be useful in CVD risk assessment. In many studies, apo B or the apo B/apoA1 ratio is independently associated with CVD risk when total and LDL-C are not and are also associated with progression of atherosclerosis in the carotid and coronary arteries. Recent studies also suggest that LDL-P > LDL-C or apoB > LDL-C discordance is common in RA.

Several studies report that compared with controls, RA patients have higher levels of small LDL-P, and higher levels of apoB (and triglycerides) despite similar LDL-C levels, similar levels of LDL-P, or lower levels of LDL-C (ie, apoB > LDL-C or LDLP > LDL-C discordance). Measuring lipoprotein particles or apolipoproteins will provide more reliable information regarding risk and effects of disease activity and medications.

For this reason, statin therapy, which reduces LDL-P, apoB, and LDL-C levels and reduces CVD events in adults with low LDL-C but elevated C-reactive protein (CRP), is very important adjunct therapy in RA patients.

Recent recommendations for dyslipidemia management from the National Lipid Association specifically address RA. Recommendations include: counting RA is as an additional atherosclerotic cardiovascular disease risk factor for risk stratification, rechecking LDL-C levels after RA flare using non-HDL-C, apoB, or LDL particle concentration instead of LDL-C when discordance exists.

A study showed that in the 5 years before RA diagnosis, levels of total and LDL-C decreased but levels of triglycerides, a strong predictor of higher apo B and LDL-P levels, did not.

Substantially Increased Burden of Atherosclerosis at Diagnosis of Rheumatoid Arthritis? Increased subclinical atherosclerosis compared with controls is seen in early RA, with faster progression of carotid intima-media thickness (cIMT) in early RA versus late RA. One study showed that in RA, non calcified plaque is more common than calcified plaque.

Emergence of Rheumatoid Arthritis Disease Activity as Key Predictor and Target for Prevention of Cardiovascular Disease Risk RA treatment seeks to reduce disease activity, assessed using various scores based on numbers of swollen and tender joints, with or without inflammatory markers such as ESR or CRP. Increasing evidence indicates that reducing RA disease activity is critical for CVD risk prevention. Several recent RA studies showed strong associations of cumulative exposure to disease activity, “flares” of disease activity, and joint pain, with increased CVD risk.

Most importantly, with anti-IL-6 treatment, greater reductions in disease activity and swollen and tender joint counts were independently related to lower CVD risk during follow-up.

A new RA-specific CVD risk calculator (ERS-RA [Extended Risk Score- Rheumatoid Arthritis]) found, in addition to traditional CVD risk factors, the following added to risk prediction: disease activity (clinical disease activity index, which does not include CRP or other inflammation markers), disability (Health Assessment Questionnaire), disease duration greater than 10 years, and prednisone use.

In contrast, seropositivity (antibodies to cyclic citrullinated peptides (anti-CCP or ACPA) or Rheumatoid Factor [RF]), erosions, and subcutaneous nodules were not significantly associated with CVD risk

Since RA-specific CVD risk factors (Box 3) are also associated with increased RA disease severity, these results suggest that RA disease activity and severity may substantially account for their associations with CVD risk. However, anti-CCP and RF may be directly related to HF and total mortality through effects on lungs or kidneys.

SUMMARY The risk of CVD and death is substantially increased among adults with RA, most of whom are postmenopausal women. Current risk factor levels, especially total and LDL-C and smoking, and CVD risk scores underestimate their risk due to an accelerated burden of subclinical atherosclerosis. Aggressive management and control of risk factors, that is, smoking cessation, antihypertensive and lipid-lowering medications, is needed, at earlier ages. Reducing disease activity and inflammation may be essential for reducing myocardial disease and fibrosis of the heart, lung, and kidney.

Further evaluation with new imaging techniques are needed to determine effects of anti-inflammatory drugs on myocardial, lung, and kidney fibrosis. Ongoing clinical trials of anti-inflammatory medications will provide important evidence about whether reducing inflammation will reduce the risk of CHD, CVD, and total mortality.