Autoimmune conditions reflect dysregulation of the immune system; this may be of clinical significance in the development of several malignancies. Previous studies show an association between systemic lupus erythematosus (SLE) and the development of malignancies; however, their investigations into the development of specific malignancies are inconsistent, and their external validity may be questionable. The main objective of this study is to investigate the association between the presence of SLE and various malignancies, in a large-scale population-based study. Data for this study was collected from Clalit Health Services, the largest state-mandated health service organization in Israel. All adult members diagnosed with SLE were included (n = 5018) and their age and sex-matched controls (n = 25,090), creating a cross-sectional population-based study. Medical records of all subjects were analyzed for documentation of malignancies. Logistic regression models were built separately for each malignant condition, controlling for age, gender, BMI, smoking, and socioeconomic status. Diagnosis of malignancy (of any type) was more prevalent in the SLE population (odds ratio [OR] 3.35, 95% confidence interval [CI] 3.02–3.72). SLE diagnosis was also found to be independently associated with higher proportions of non-Hodgkin lymphoma (OR 3.02, 95% CI 2.72–3.33), Hodgkin lymphoma (OR 2.43, 95% CI 1.88–2.99), multiple myeloma (OR 2.57, 95% CI 1.85–3.28), cervix uteri malignancies (OR 1.65, 95% CI 1.10–2.20), and genital organ malignancies (OR 2.32, 95% CI 1.42–3.22), after adjustment for confounding variables. The presence of an SLE diagnosis was found to be independently associated with higher proportions of malignancies, particularly hematologic malignancies. These findings should be considered while treating SLE patients, and possibly supplement their screening routine.
