#1505 Late-onset lupus nephritis: clinical-epidemiological, histological, prognostic and therapeutical implications: a single center experience

Abstract

Abstract Background and Aims Systemic lupus erythematosus (SLE), a chronic autoimmune disease, and lupus nephritis (LN), are typically diagnosed in women in fertile age. Late-onset SLE is defined as a disease onset over 50 years. Our main objective was to analyze the clinical, histological, prognostic and therapeutical features related to LN in our late-onset SLE population. Method A single center and retrospective study was performed comparing clinical-demographic, histological, prognostic and therapeutical data of 45 LN biopsied patients from 1994 to 2023. We divided the study population according to the age of onset of LN into classic-onset (< 45 years) and late-onset (> 45 years). Results Late-onset LN patients showed a higher association with Sjögren's and antiphospholipid syndrome, more cardiovascular comorbidities at presentation, poorer renal function at diagnosis and higher SDI score. On histology they showed more non-proliferative LN classes (II followed by V). Late-onset LN responders needed more time to achieve response but had fewer relapses. Non responsive patients had more incidence of acute kidney injury (AKI) and more glomerulosclerosis and interstitial fibrosis-tubular atrophy (IFTA) at presentation, as well as more need for renal replacement therapy (RRT) at diagnosis and at follow-up. The principal independent variables associated with relapse were the younger age at SLE diagnosis and an initial partial renal response (PRR). Patients of both groups who experienced relapse received higher doses of intravenous cyclophosphamide and less mycophenolic acid (MFA) analogues. Patients who received induction with MFA analogues were more likely to achieve complete renal response (CRR) or non-renal response (NRR). Conclusion late-onset LN is often accompanied by poor renal function at presentation. It seems imperative to establish a tailored approach in this fragile population in order to avoid unnecessary immunosuppression.