Heart Disease in Lupus More Common than Previously Thought

Cardiovascular disease (CVD) is a leading cause of mortality in systemic lupus erythematous (SLE) patients, but the risk of CVD in these patients could be higher than previously thought, researchers reported at EULAR 2017.

The risk of cardiovascular disease is usually determined by the Framingham Risk Score, but Karim Sacre, M.D., of Paris University, says that this measure may underestimate CVD risk in the lupus population.

“The Framingham score is dependent on several factors, including age. In lupus patients, we know that when cardiovascular events occur, they occur 10 years earlier than in the general population. In the general population, age carries more weight than it does for lupus patients, which is why the score underestimates risk,” he said.

Dr. Sacre and colleagues may have come up with a more accurate measure of CVD in lupus patients. By measuring concentrations of the serum High Sensitivity Cardiac Troponin T (HS-cTnT), they discovered an association between high concentrations of HS-cTnT and subclinical atherosclerosis in asymptomatic lupus patients for whom traditional risk factors would have indicated a low risk of CVD.

In a sample of 63 SLE patients and 18 controls, they found that HS-cTnT concentrations were independently associated with subclinical atherosclerosis in asymptomatic SLE patients who were previously determined to be at low risk for CVD. “These results raise the possibility that this easily obtained biomarker is useful for more rigorous risk stratification and primary prevention of CVD in SLE patients,” researchers wrote.

Though the Framingham score was found to be low in both SLE patients (2.1±3.8%) and controls (2.1±2.9%), this test was more revealing. Of 23 SLE patients (36.5%) who had carotid plaques as confirmed by vascular ultrasound, 87% had detectable HS-cTnT as compared to 11.1% of controls (two patients, p=0.039). By comparison, 42.5% of SLE patients without plaques (p<0.001) had detectable HS-cTnT. In total, serum HS-cTnT concentrations of greater than 3 ng/L were detectable in 37 (58.7%) SLE patients and 6 controls (33.3%) (p=0.057).  In the multivariate analysis, only age (p=0.006) and SLE status (p=0.017) were independently associated with carotid plaques.

Conversely, 54.5% SLE patients with a detectable HS-cTnT, but only 11.5% with an undetectable HS-cTnT (p<0.001), had a carotid plaque. In the multivariate analysis, only BMI (p=0.006) and HS-cTnT (p=0.033) were statistically associated with carotid plaques in SLE patients. Overall, the risk of having a carotid plaque was increased by 8 (OR [95%CI]: 8.03 [1.41-74.73]) in SLE patients in whom HS-cTnT was detectable in serum.

These findings need to be confirmed in larger trials, Dr. Sacre said. “We hope that in the biomarker Troponin, detected by highly sensitive [serum concentrations], we have better certified the risk of cardiovascular events in lupus patients.”

If this biomarker is indeed confirmed to offer a more accurate predictor of cardiovascular disease in lupus, it could be used as a tool in clinical practice to guide preventative care measures. “These results raise the possibility that this easily obtained biomarker is useful for more rigorous risk stratification and primary prevention of CVD in SLE patients,” researchers stated.

References:

G. Divard, R. Abbas, C. Chenevier-Gobeaux, et al. “High Sensitivity Cardiac Troponin T is a Biomarker for Atherosclerosis in Systemic Lupus Erythematous Patients: A Cross-Sectional Controlled Study,” EULAR 2017. Abstract:  OP0319