Hematological malignancies in systemic lupus erythematosus: clinical characteristics, risk factors, and prognosis-a case-control study

Background Systemic lupus erythematosus (SLE) is a chronic and complex multi-system autoimmune disorder. Higher risks of hematological malignancies (HM) were observed in SLE patients, which was associated with higher mortality. The mechanism and risk factors of HM oncogenesis in SLE patients are still under investigation. The aim of this study was to explore clinical characteristics, risk factors, and prognosis of SLE patients with or without HM in the Chinese population. Methods A retrospective, case-controlled study was conducted in 72 SLE patients between January 2013 and December 2020. Clinical and laboratory data were collected and compared between the two groups of patients with HM and those without HM. Logistic regression analysis was performed to determine risk factors of HM oncogenesis. The survival rate was estimated by Kaplan-Meier methods and Cox proportional hazards regression analysis. Results Among 72 SLE patients in this study, fifteen complicated with HM and 57 without HM were identified. The incidence rate of HM was approximately 0.24% with elevated standardized incidence ratios of lymphoma and leukemia (27.559 and 12.708, respectively). Patients with HM were older when diagnosed with SLE, with a higher frequency of infection and splenomegaly, lower levels of hemoglobin and high-density lipoprotein compared with those without HM. Fewer patients with HM expressed positive anti-dsDNA antibody (26.7% vs 66.7%, P = 0.005) or received hydroxychloroquine treatment (40.0% vs 86.0%, P = 0.001). Older age at SLE diagnosis (OR=1.122, 95% CI: 1.037-1.214) was regarded as an independent risk factor of HM oncogenesis. Female (RR= 0.219, 95% CI: 0.070-0.681) and hydroxychloroquine (RR= 0.281, 95% CI: 0.094-0.845) were protective factors of mortality in SLE patients. Conclusions SLE patients with an older age are at an increased risk of HM carcinogenesis. The prognosis of male patients with SLE tends to be poorer whether complicated with HM. The association of antinuclear antibody spectrum, medication, and HM oncogenesis in SLE needs further investigation.