A tool that incorporates lupus-related variables with traditional risk factors provides a much more accurate assessment of cardiovascular (CV) risk in patients with systemic lupus erythematosus (SLE), according to data presented at the annual meeting of the Canadian Rheumatology Association.
In the initial clinical assessment of this tool, called the SLECRISK, “it identified high-risk lupus patients who would otherwise be missed by traditional methods of CV risk assessment,” reported May Y. Choi, MD, associate director of translational research at the University of Calgary’s (Alta.) Lupus Centre of Excellence.
It is well known that patients with SLE face an increased risk of CV events starting at an age long before risk begins climbing in the general population, according to Dr. Choi. She cited one study that showed women aged 35-44 years have a 50-fold greater risk of myocardial infarction than healthy individuals.
All major guidelines recognize this increased risk and recommend CV risk assessment in patients with SLE, even though Dr. Choi pointed out that traditional tools, such as the American College of Cardiology atherosclerotic cardiovascular disease (ASCVD) risk calculator or the Framingham Risk Score (FRS) have a limited ability to detect the patients with SLE who are most likely to have an event.
In SLE, current tools are inadequate
“These risk assessment tools perform poorly in SLE patients because they do not capture SLE-related inflammation,” Dr. Choi said. Of several examples, Dr. Choi cited a study showing “seven times more MIs and strokes observed than expected in SLE patients on the basis of the FRS.”
The disparity between expected and observed MIs and strokes is worse with increasing severity of SLE. In a study she presented 3 years ago, rates of CV events were 12 times higher in those with inactive or mild SLE, rising to a 16-fold increase among those with moderate disease and jumping to a 32-fold increase in those with severe SLE.
The SLECRISK tool was developed from the Brigham and Women’s Hospital SLE Registry, which was initiated in 1992. Patients without a history of CV disease were evaluated for traditional CV risk factors and for SLE-specific characteristics such as disease activity, levels of the complement proteins C3 and C4, kidney function, the presence of nephritis, and SLE duration. The value of these characteristics as predictors of CV events were then assessed over a 10-year follow-up period before being assembled into the SLECRISK tool.
In an example of the risk equation, Dr. Choi described a 50-year-old patient with SLE and a 5% 10-year ASCVD risk score, which is low. After adjustment for SLE risks, which included 10 years disease duration, high disease activity, elevated creatinine, and positive anti–double stranded DNA status, the 10-year CV risk score climbed to 16.2%, which is moderate.
The performance of the SLECRISK was evaluated in 1,243 patients providing 8,946.51 person-years of follow-up. During this period, there were 90 major adverse cardiac events (MACE), of which 82% were adjudicated by cardiologists, and 211 secondary events.
Relative to the ASCVD risk score, the SLECRISK identified about twice as many patients with SLE as having moderate risk and 3.5-fold more patients as having high risk. Among patients who experienced CV events, traditional CV risk factors were more common but so were SLE-specific risk factors, including greater disease severity, a greater likelihood of lupus nephritis, increased complement levels, and greater exposure to glucocorticoids, according to Dr. Choi.
Specificities for CV events higher on SLECRISK
In predicting CV events, the differences in specificities were in the same general range, although somewhat higher for the ASCVD risk score in regard to predicting MACE (83% vs. 72%) and MACE plus secondary events (90% vs. 79%). However, the sensitivities were much higher for SLECRISK relative to the ASCVD risk score for MACE alone (64% vs. 41%) and for MACE plus secondary events (58% vs. 35%).
When comparing those who had an MI or stroke, the ASCVD risk score identified 8 (7%) patients missed by SLECRISK, whereas SLECRISK identified 89 (73%) missed by the ASCVD risk score. The remaining 25 patients (20%) were identified by both. The advantage of SLECRISK was similar for MACE plus secondary outcomes.
Dr. Choi noted that all of the SLE-specific variables in SLECRISK are readily obtained and often already available in patient charts. She said that there is a plan to validate the tool in larger groups, but with a goal of creating a tool available online for clinicians and their patients to use. There is also an even more ambitious plan for the future.
“We have funding to look at machine learning to evaluate predictive variables in SLE patients,” Dr. Choi said. Rather than adding SLE-specific variables to traditional risks, the plan is to “start from scratch,” letting artificial intelligence assemble predictors without prejudice to what might or might not be relevant.
A SLE-specific tool for evaluating CV risk is an important “unmet need,” according to Karen H. Costenbader, MD, professor in the division of rheumatology, inflammation, and immunity at Brigham and Women’s Hospital and Harvard Medical School, both in Boston. In an interview, she reiterated that measuring CV risk in SLE is already guideline recommended, but conventional tools have been shown to be inaccurate.
“I can envision it being used in clinical encounters to help guide shared decision-making with patients,” explained Dr. Costenbader, who was not involved in the presentation at the CRA meeting but worked with Dr. Choi in developing SLECRISK. “It would give us more precise estimates, allowing us to risk stratify our patients and informing us as to which modifiable SLE-specific and nonspecific factors are contributing most to CV risk.”
The problem of using conventional risk assessments in SLE has been well recognized. Of those who have written on this subject, Maureen McMahon, MD, site director of the Lupus Clinical Trials Network at the University of California, Los Angeles, said: “There is a critical need for the development of SLE-specific risk assessment tools like SLECRISK.”
Author of several studies looking at alternatives for CV risk assessment in SLE, including a study looking at a panel of biomarkers that was published in ACR Open Rheumatology, Dr. McMahon said in an interview that CV risk in SLE is high but conventional risk assessments are flawed.
“Multiple previous studies have demonstrated that these currently available calculators are not adequate for identifying risk in the lupus patient population,” she said. According to Dr. McMahon, the fact that rheumatologists remain “dependent upon [these conventional] cardiovascular risk calculators” is a well-recognized problem that needs resolution.
Dr. Choi has financial relationships with AstraZeneca, GlaxoSmithKline, Mallinckrodt. MitogenDx, Organon, and Werfen International. Dr. Costenbader reports no potential conflicts of interest. Dr. McMahon has financial relationships with AstraZeneca, Aurinia Pharmaceuticals, Eli Lilly, and GlaxoSmithKline.
This story originally appeared on MDedge.com, part of the Medscape Professional Network.
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