Late-Onset Systemic Lupus Erythematosus: Clinical Features, Comorbidities, and Mortality in a Single-Center Cohort

Background: Late-onset systemic lupus erythematosus (Lo-SLE) is a rare subgroup of SLE characterized by disease onset at ≥50 years of age and a distinct clinical phenotype. This study aims to evaluate the clinical and laboratory characteristics, comorbidities, and mortality rates of Lo-SLE patients treated at our center. Materials and Methods: This single-center retrospective study included Lo-SLE patients diagnosed with SLE at our center between 2010 and 2025 and whose disease onset age was ≥50 years. The patients’ demographic characteristics, clinical findings, organ involvement, laboratory data, and treatments administered were obtained from medical records. Additionally, comorbidities, mortality rates, and causes of death were analysed. Results: The mean age at SLE diagnosis for the 39 Lo-SLE patients included in the study was 57.8±6.5 years, and 82.1% of the patients were female. The most common clinical findings were hematological abnormalities; renal involvement was detected at a relatively lower frequency. One patient was diagnosed with transverse myelitis. The positivity rates for anti-nuclear antibody (ANA) and anti-dsDNA were 100% and 82.1%, respectively. During a mean follow-up period of 8.2±6.8 years, the most common comorbidity was hypertension (46.2%), and malignancy developed in 4 (10.3%) patients. All patients used hydroxychloroquine during follow-up, while 79.5% of patients received steroids and 59% received at least one immunosuppressive treatment. The mortality rate in the cohort was 35.9%, with the most common causes of death being cardiovascular diseases and infections. Conclusion: Our single-center experience shows that hematological involvement, such as autoimmune hemolytic anemia and immune thrombocytopenia, is more common in Lo-SLE patients, but that a diagnosis can also be made with neurological findings, such as transverse myelitis, in rare cases. It should be kept in mind that malignancies, as well as comorbidities such as hypertension, may be seen in the Lo-SLE group, and cardiovascular diseases and infections are important causes of mortality.