Clinical and Pathological Characteristics of Lupus Nephritis in Elderly Patients

Background: Systemic lupus erythematosus (SLE) predominantly affects young women and is frequently complicated by lupus nephritis. Less than 10% of SLE cases manifest after the age of 65 years and lupus nephritis is less prevalent in elderly SLE patients. The prognosis of lupus nephritis in the elderly could be poor owing to numerous complications. Despite its clinical significance, the clinical and pathological characteristics of lupus nephritis in the elderly population remain unclear, and we investigated the data from our institution. Methods: We retrospectively collected data from 40 patients diagnosed with lupus nephritis by renal biopsy between 2017 and 2023 at our hospital. We obtained data at the time of renal biopsy and after treatment, and the patients were divided into two age groups: younger (< 65 years) and older (≥ 65 years) patients. Statistical analyses were conducted using t-tests and chi-squared tests. Additionally, the outcomes were assessed in these patients. Results: There were 8 patients (5 women and 3 men) in the elderly group and 32 patients (29 women and 3 men) in the younger group. Compared to the younger group, the elderly group exhibited significantly lower levels of eGFR, anti-DNA antibody, and anti-Sm antibodies. There were no significant differences in BMI, blood pressure, serum albumin, C3, C4, CH50, urinary RBC score, urinary protein or the frequency of rapid progressive glomerulonephritis. The most common renal histologic type in the elderly patients was ISN/RPS Class IV (± V) (3 patients). 75 percent of the elderly patients underwent treatment with steroids, and 83.3% of them additionally received immunosuppressive drugs. The complete or partial remission rate of lupus nephritis among the treated elderly patients was 83.3%. Two patients died from infection (within 2 months of starting treatment) and CO2 narcosis, respectively. Conclusion: We revealed the clinical and pathological characteristics of lupus nephritis in elderly patients. Lower eGFR and titers of specific antibodies were observed in the elderly patients than in the younger patients. Although the remission rate with treatment was favorable, mortality due to infection, which was likely associated with immunosuppression, was noted. Management strategies for lupus nephritis in elderly patients should carefully consider the risk of infection.