Malignancies in lupus nephritis: a retrospective cohort study on epidemiology and risk factors

OBJECTIVES: This study aimed to evaluate the epidemiology and predisposing factors for malignancy in lupus nephritis (LN). METHODS: This retrospective cohort study included 290 patients diagnosed with LN from 1969 to 2023. Demographic and clinical variables were analysed using the Mann-Whitney U test and Fisher's test. To identify predictors of cancer development, univariate logistic regression analysis was conducted. RESULTS: Over a median follow-up period of 15 years (IQR 6-25), 27 malignancies were diagnosed (prevalence 9.3%, incidence 6.08 per 1000 person-years), 22.2% affecting the urinary tract and 33.3% the skin. Cancer diagnoses were evenly distributed across the decades of observation and 85.2% occurred during a quiescent phase of LN. Mortality was significantly higher in patients with malignancies compared with those without (25.9% vs 6.9%, p=0.012). Patients with malignancies were significantly older at LN diagnosis (31.6 vs 28.7 years, p=0.035) and at the end of follow-up (58.1 years vs 45.2 years, p