Severe renal arteriosclerosis was associated with a ninefold increased risk of atherosclerotic cardiovascular disease in patients with lupus nephritis, based on data from an observational study of 189 individuals.
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Atherosclerotic cardiovascular disease (ASCVD) has traditionally been thought to be a late complication of systemic lupus erythematosus (SLE), but this has been challenged in recent population-based studies of patients with SLE and lupus nephritis (LN) that indicated an early and increased risk of ASCVD at the time of diagnosis. However, it is unclear which early risk factors may predispose patients to ASCVD, Shivani Garg, MD, of the University of Wisconsin, Madison, and colleagues wrote in a study published in Arthritis Care & Research.
In patients with IgA nephropathy and renal transplantation, previous studies have shown that severe renal arteriosclerosis (r-ASCL) based on kidney biopsies at the time of diagnosis predicts ASCVD, but “a few studies including LN biopsies failed to report a similar association between the presence of severe r-ASCL and ASCVD occurrence,” possibly because of underreporting of r-ASCL. Dr. Garg and colleagues also noted the problem of underreporting of r-ASCL in their own previous study of its prevalence in LN patients at the time of diagnosis.
To get a more detailed view of how r-ASCL may be linked to early occurrence of ASCVD in LN patients, Dr. Garg and coauthors identified 189 consecutive patients with incident LN who underwent diagnostic biopsies between 1994 and 2017. The median age of the patients was 25 years, 78% were women, and 73% were white. The researchers developed a composite score for r-ASCL severity based on reported and overread biopsies.
Overall, 31% of the patients had any reported r-ASCL, and 7% had moderate-severe r-ASCL. After incorporating systematically reexamined r-ASCL grades, the prevalence of any and moderate-severe r-ASCL increased to 39% and 12%, respectively.
Based on their composite of reported and overread r-ASCL grade, severe r-ASCL in diagnostic LN biopsies was associated with a ninefold increased risk of ASCVD.
The researchers identified 22 incident ASCVD events over an 11-year follow-up for an overall 12% incidence of ASCVD in LN. ASCVD was defined as ischemic heart disease (including myocardial infarction, coronary artery revascularization, abnormal stress test, abnormal angiogram, and events documented by a cardiologist); stroke and transient ischemic attack (TIA); and peripheral vascular disease. Incident ASCVD was defined as the first ASCVD event between 1 and 10 years after LN diagnosis.
The most common ASCVD events were stroke or TIA (12 patients), events related to ischemic heart disease (7 patients), and events related to peripheral vascular disease (3 patients).
Lack of statin use
The researchers also hypothesized that the presence of gaps in statin use among eligible LN patients would be present in their study population. “Among the 20 patients with incident ASCVD events after LN diagnosis in our cohort, none was on statin therapy at the time of LN diagnosis,” the researchers said, noting that current guidelines from the American College of Rheumatology and the European League Against Rheumatism (now known as the European Alliance of Associations for Rheumatology) recommend initiating statin therapy at the time of LN diagnosis in all patients who have hyperlipidemia and chronic kidney disease (CKD) stage ≥3. “Further, 11 patients (55%) met high-risk criteria (hyperlipidemia and CKD stage ≥3) to implement statin therapy at the time of LN diagnosis, yet only one patient (9%) was initiated on statin therapy.” In addition, patients with stage 3 or higher CKD were more likely to develop ASCVD than patients without stage 3 or higher CKD, they said.
The study findings were limited by several factors including the majority white study population, the ability to overread only 25% of the biopsies, and the lack of data on the potential role of chronic lesions in ASCVD, the researchers noted. However, the results were strengthened by the use of a validated LN cohort, and the data provide “the basis to establish severe composite r-ASCL as a predictor of ASCVD events using a larger sample size in different cohorts,” they said.
The study received no outside funding. The researchers had no financial conflicts to disclose.