Lupus Erythematosus

Hydroxychloroquine and Cardiovascular Events in Patients With Systemic Lupus Erythematosus

Author/s: 
Lamiae Grimaldi, Tom Duchemin, Yann Hamon, Albert Buchard, Jacques Benichou

Importance: Systemic lupus erythematosus (SLE) predisposes individuals to early cardiovascular (CV) events. While hydroxychloroquine is thought to mitigate CV risk factors, its protective role against CV events, particularly arterial ones, remains to be confirmed.

Objective: To evaluate the association between hydroxychloroquine and the risk of myocardial infarction (MI), stroke, and other thromboembolic events (OTEs) in patients with SLE.

Design, setting, and participants: This cohort study using a nested case-control design was conducted within the National French Healthcare Database (SNDS), which represents 99% of the French population, from 2010 to 2020. Participants were the cohort of all patients with SLE recorded in the SNDS. Patients with SLE experiencing CV events during the study period were the case group; those without CV events were controls. The analysis period was from February 2022 to September 2023.

Exposures: Hydroxychloroquine use within 365 days prior to the index date, defined as current (within 90 days), remote (91-365 days), or no exposure within the previous 365 days.

Main outcomes and measures: Outcomes of interest were MI, stroke, and OTE, analyzed individually and as a composite outcome (primary analysis). Controls were matched to patients with CV events by age, sex, time since SLE onset and entry into the SNDS database, index date, prior antithrombotic and CV medication, chronic kidney disease, and hospitalization. Multivariable conditional logistic regression was performed using hydroxychloroquine exposure as the main independent variable.

Results: The SLE cohort included 52 883 patients (mean [SD] age, 44.23 [16.09] years; 45 255 [86.6%] female; mean [SD] follow-up, 9.01 [2.51] years), including 1981 patients with eligible CV events and 16 892 matched control patients. There were 669 MI events, 916 stroke events, and 696 OTEs in the individual outcome studies. For current exposure to hydroxychloroquine, the adjusted odds were lower for composite CV events (odds ratio [OR], 0.63; 95% CI, 0.57-0.69) as well as for MI (OR, 0.72; 95% CI, 0.60-0.85), stroke (OR, 0.69; 95% CI, 0.60-0.81), and OTEs (OR, 0.58; 95% CI, 0.49-0.69) individually compared with no hydroxychloroquine exposure within 365 days.

Conclusions and relevance: In this nationwide cohort study of patients with SLE, a protective association was found between the current use of hydroxychloroquine and the occurrence of CV events, but not between remote use of hydroxychloroquine and CV outcomes, highlighting the value of continuous hydroxychloroquine treatment in patients with SLE.

Systemic Lupus Erythematosus: A Review

Author/s: 
Siegel, C.H., Sammaritano, L.R.

Importance
Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by inflammation and immune-mediated injury to multiple organ systems, including the mucocutaneous, musculoskeletal, hematologic, and kidney systems. Approximately 3.4 million people worldwide have received a diagnosis of SLE.

Observations
Approximately 90% of people with SLE are female. Although there are no uniformly accepted diagnostic criteria for SLE, the 2019 European Alliance of Associations for Rheumatology (formerly the European League Against Rheumatism)/American College of Rheumatology classification criteria developed for scientific study are an estimated 96.1% sensitive and 93.4% specific for SLE. These classification criteria include both clinical factors, such as fever, cytopenia, rash, arthritis, and proteinuria, which may be indicative of lupus nephritis; and immunologic measures, such as SLE-specific autoantibodies and low complement levels. Approximately 40% of people with SLE develop lupus nephritis, and an estimated 10% of people with lupus nephritis develop end-stage kidney disease after 10 years. The primary goal of treatment is to achieve disease remission or quiescence, defined by minimal symptoms, low levels of autoimmune inflammatory markers, and minimal systemic glucocorticoid requirement while the patient is treated with maintenance doses of immunomodulatory or immunosuppressive medications. Treatment goals include reducing disease exacerbations, hospitalizations, and organ damage due to the disease or treatment toxicity. Hydroxychloroquine is standard of care for SLE and has been associated with a significant reduction in mortality. Treatments in addition to hydroxychloroquine are individualized, with immunosuppressive agents, such as azathioprine, mycophenolate mofetil, and cyclophosphamide, typically used for treating moderate to severe disease. Three SLE medications were recently approved by the Food and Drug Administration: belimumab (for active SLE in 2011 and for lupus nephritis in 2020), voclosporin (for lupus nephritis), and anifrolumab (for active SLE).

Conclusions and Relevance
Systemic lupus erythematosus is associated with immune-mediated damage to multiple organs and increased mortality. Hydroxychloroquine is first-line therapy and reduces disease activity, morbidity, and mortality. When needed, additional immunosuppressive and biologic therapies include azathioprine, mycophenolate mofetil, cyclophosphamide, belimumab, voclosporin, and anifrolumab.

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